Building Awesome CLI apps in Go
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This document provides an overview of building a command line interface (CLI) application in Go. It discusses UX considerations for CLIs, common CLI patterns and philosophies, and Go-specific topics. Some key points include: - CLI apps should follow Unix philosophies of being simple, clear, composable, and extensible. - Common CLI patterns include commands, arguments, options/flags, and subcommands. - Go is a statically typed, compiled language with built-in concurrency and a large standard library. - The document concludes by outlining plans to build a sample TODO app in Go called "Tri" to demonstrate CLI design and development.
![› rm [file]
› cp [file] [newfile]
c:copy [file] [newfile]
INPUT
28](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-28-320.jpg)
![> rm [file] ... [fileN]
MANY INPUTS
29
Arg0 Argn](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-29-320.jpg)
![> cp [file] [newfile]
ORDER MATTERS
30
From To](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-30-320.jpg)
![> cp [file] [newfile]
SEPARATED
31
Space separates](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-31-320.jpg)
![> cp [file] [newfile]
DIRECT OBJECT
33
Verb Noun Noun](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-33-320.jpg)
![> cp [file] [newfile]
IS PROUNCABLE
34
Copy this file to here](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-34-320.jpg)
![› rm [options] [file]
c:del [options] [file]
MODIFY ACTIONS
37](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-37-320.jpg)
![› rm --force [file]
ADVERB
45
Verb Adverb Noun](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-45-320.jpg)
![› rm --force [file]
PRONOUNCEABLE
46
Forcefully remove
this file](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-46-320.jpg)
![› rm --force [file]
PRONOUNCEABLE
47
remove this file
with Force](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-47-320.jpg)
![Extract: tar -x [options]
-k Keep existing files
-m Don't restore mod times
FLAGS HAVING SUB FLAGS
67](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-67-320.jpg)
![Create: tar -c [options]
-z, -j, -J, --lzma
Compress archive with gzip/
bzip2/xz/lzma
FLAGS HAVING SUB FLAGS
68](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-68-320.jpg)
![ls [options]
-S sort by file size
-t sort by modification time
-U do not sort
...
INCOMPATIBLE FLAGS
70](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-70-320.jpg)
![> ls
--sort=[size,modtime,none]
BETTER
72](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-72-320.jpg)
![› cobra
Cobra is a Cli library for Go that empowers applications. This
application is a tool to generate the needed files to quickly
create a Cobra application.
Usage:
cobra [command]
Available Commands:
add Add a command to a Cobra Application
COBRA
197](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-197-320.jpg)
![var addCmd = &cobra.Command{
Use: "add",
Short: "A brief description of your command",
Long: `A longer description that spans multiple
lines and likely...`,
Run: func(cmd *cobra.Command, args []string) {
// TODO: Work your own magic here
fmt.Println("add called")
},
}
CMD/ADD.GO
231](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-231-320.jpg)
![var addCmd = &cobra.Command{
Use: "add",
Short: "Add a new todo",
Long: `Add will create a new todo item to the list`,
Run: func(cmd *cobra.Command, args []string) {
// TODO: Work your own magic here
fmt.Println("add called")
},
}
CMD/ADD.GO
232](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-232-320.jpg)
![func addRun(cmd *cobra.Command,
args []string){
fmt.Println("add called")
}
CMD/ADD.GO
233](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-233-320.jpg)
![func addRun(cmd *cobra.Command,
args []string) {
for _, x := range args {
fmt.Println(x)
}
}
CMD/ADD.GO
235](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-235-320.jpg)
![func addRun(...) {
items := []todo.Item{}
for _, x := range args {
items = append(items, todo.Item{Text:x})
}
fmt.Println(items)
}
CMD/ADD.GO
247](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-247-320.jpg)
![func addRun(...) {
items := []todo.Item{}
for _, x := range args {
items = append(items, todo.Item{Text:x})
}
fmt.Println(items)
}
CMD/ADD.GO
248](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-248-320.jpg)
![func addRun(...) {
items := []todo.Item{}
for _, x := range args {
items = append(items, todo.Item{Text:x})
}
fmt.Println(items)
}
CMD/ADD.GO
250](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-250-320.jpg)
![func addRun(...) {
items := []todo.Item{}
for _, x := range args {
items = append(items, todo.Item{Text:x})
}
fmt.Println(items)
}
CMD/ADD.GO
251](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-251-320.jpg)
![>go run main.go add
"one two" three
[{one two} {three}]
GO RUN
252](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-252-320.jpg)
![func addRun(...) {
var items = []todo.Item{}
for _,x := range args {
items = append(items, todo.Item{Text:x})
}
fmt.Printf("%#vn", items)
}
CMD/ADD.GO
253](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-253-320.jpg)
![>go run main.go add
"one two" three
[]todo.Item{todo.Item{Text:
"one two"},
todo.Item{Text:"three"}}
GO RUN
254](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-254-320.jpg)
![func SaveItems(filename string,
items []Item) error {
return nil
}
TODO/TODO.GO
257](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-257-320.jpg)
![func SaveItems(filename string, items []Item) error {
b, err := json.Marshal(items)
if err != nil {
return err
}
fmt.Println(string(b))
return nil
}
TODO/TODO.GO
260](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-260-320.jpg)
![func SaveItems(filename string, items []Item) error {
b, err := json.Marshal(items)
if err != nil {
return err
}
fmt.Println(string(b))
return nil
}
TODO/TODO.GO
261](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-261-320.jpg)
![func SaveItems(filename string, items []Item) error {
b, err := json.Marshal(items)
if err != nil {
return err
}
fmt.Println(string(b))
return nil
}
TODO/TODO.GO
262](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-262-320.jpg)
![func SaveItems(filename string, items []Item) error {
b, err := json.Marshal(items)
if err != nil {
return err
}
fmt.Println(string(b))
return nil
}
TODO/TODO.GO
265](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-265-320.jpg)
![func addRun(cmd *cobra.Command,
args []string) {
var items = []todo.Item{}
for _, x := range args {
items = append(items, todo.Item{Text: x})
}
todo.SaveItems("x", items)
}
CMD/ADD.GO
266](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-266-320.jpg)
![>go run main.go add
"one two" three
[{"Text":"one two"},
{"Text":"three"}]
CHECK JSON CREATION
267](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-267-320.jpg)
![func SaveItems(filename string, items []Item) error {
...
err = ioutil.WriteFile(filename, b, 0644)
if err != nil {
return err
}
return nil
}
TODO/TODO.GO
270](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-270-320.jpg)
![func addRun(cmd *cobra.Command,
args []string) {
var items = []todo.Item{}
for _, x := range args {
items = append(items, todo.Item{Text: x})
}
err := todo.SaveItems("/Users/spf13/.tridos.json", items);
if err != nil {
fmt.Errorf("%v", err)
}
}
CMD/ADD.GO
271](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-271-320.jpg)
![› go run main.go add "one two" three
› cat ~/.tridos.json
[{"Text":"one two"},
{"Text":"three"}]
CHECK FILE CREATION
272](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-272-320.jpg)
![func ReadItems(filename
string) ([]Item, error) {
return []Item{}, nil
}
TODO/TODO.GO
274](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-274-320.jpg)
![func ReadItems(filename
string) ([]Item, error) {
return []Item{}, nil
}
TODO/TODO.GO
275](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-275-320.jpg)
![func ReadItems(filename string)
([]Item, error) {
b, err := ioutil.ReadFile(filename)
if err != nil {
return []Item{}, err
}
...
TODO/TODO.GO
276](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-276-320.jpg)
![func ReadItems(filename string)
([]Item, error) {
b, err := ioutil.ReadFile(filename)
if err != nil {
return []Item{}, err
}
...
TODO/TODO.GO
277](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-277-320.jpg)
![func ReadItems(filename string) ([]Item, error) {
...
var items []Item
if err := json.Unmarshal(b, &items); err != nil {
return []Item{}, err
}
return items, nil
}
TODO/TODO.GO
278](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-278-320.jpg)
![func ReadItems(filename string) ([]Item, error) {
...
var items []Item
if err := json.Unmarshal(b, &items); err != nil {
return []Item{}, err
}
return items, nil
}
TODO/TODO.GO
279](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-279-320.jpg)
![func ReadItems(filename string) ([]Item, error) {
...
var items []Item
if err := json.Unmarshal(b, &items); err != nil {
return []Item{}, err
}
return items, nil
}
TODO/TODO.GO
280](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-280-320.jpg)
![func ReadItems(filename string) ([]Item, error) {
...
var items []Item
if err := json.Unmarshal(b, &items); err != nil {
return []Item{}, err
}
return items, nil
}
TODO/TODO.GO
281](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-281-320.jpg)
![func ReadItems(filename string) ([]Item, error) {
...
var items []Item
if err := json.Unmarshal(b, &items); err != nil {
return []Item{}, err
}
return items, nil
}
TODO/TODO.GO
282](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-282-320.jpg)
![Run: func(cmd *cobra.Command, args []string) {
items, err := todo.ReadItems("/Users/
spf13/.tridos.json")
if err != nil {
log.Printf("%v", err)
}
fmt.Println(items)
},
CMD/LIST.GO
285](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-285-320.jpg)
![Run: func(cmd *cobra.Command, args []string) {
items, err := todo.ReadItems("/Users/
spf13/.tridos.json")
if err != nil {
log.Printf("%v", err)
}
fmt.Println(items)
},
CMD/LIST.GO
286](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-286-320.jpg)
![Run: func(cmd *cobra.Command, args []string) {
items, err := todo.ReadItems("/Users/
spf13/.tridos.json")
if err != nil {
log.Printf("%v", err)
}
fmt.Println(items)
},
CMD/LIST.GO
287](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-287-320.jpg)
![› go run main.go list
[{one two} {three}]
RUN LIST
288](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-288-320.jpg)
![func addRun(cmd *cobra.Command, args []string) {
var items = []todo.Item{}
for _, x := range args {
items = append(items, todo.Item{Text: x})
}
...
CMD/ADD.GO
289](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-289-320.jpg)
![func addRun(cmd *cobra.Command, args []string) {
items, err := todo.ReadItems("/Users/spf13/.tridos.json")
if err != nil {
log.Printf("%v", err)
}
for _, x := range args {
items = append(items, todo.Item{Text: x})
}
...
CMD/ADD.GO
290](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-290-320.jpg)
![› go build
› ./tri
...
Flags:
--datafile string data file to store todos (default "/
Users/spf13/.tridos.json")
-h, --help help for tri
Use "tri [command] --help" for more information about a
command.
SEE THE FLAG
304](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-304-320.jpg)
![› go build
› ./tri add "Add priorities"
--datafile $HOME/.next.json
› ./tri list --datafile $HOME/.next.json
[{Add priorities}]
USE THE FLAG
305](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-305-320.jpg)
![› go build
› ./tri help add
Add will create a new todo item to the list
Usage:
tri add [flags]
Flags:
-p, --priority int Priority:1,2,3 (default 2)
HELP ADD
317](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-317-320.jpg)
![func addRun(cmd *cobra.Command, args []string) {
...
for _, x := range args {
item := todo.Item{Text: x}
item.SetPriority(priority)
items = append(items, item)
}
CMD/ADD.GO
319](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-319-320.jpg)
![func addRun(cmd *cobra.Command, args []string) {
...
for _, x := range args {
item := todo.Item{Text: x}
item.SetPriority(priority)
items = append(items, item)
}
CMD/ADD.GO
320](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-320-320.jpg)
![› ./tri add "format list" -p1
› ./tri list
[{add priorities 0} {order by
priority 0} {format list 1}]
ADD WITH PRIORITY
321](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-321-320.jpg)
![// listCmd respresents the list command
var listCmd = &cobra.Command{
Use: "list",
Short: "List the todos",
Long: `Listing the todos`,
Run: listRun,
}
func listRun(cmd *cobra.Command, args []string) {
...
}
CMD/LIST.GO
324](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-324-320.jpg)
![func listRun(cmd *cobra.Command, args []string) {
...
w := tabwriter.NewWriter(os.Stdout, 3, 0, 1, ' ', 0)
for _, i := range items {
fmt.Fprintln(w, strconv.Itoa(i.Priority)+"t"+i.Text+"t")
}
w.Flush()
}
CMD/LIST.GO
326](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-326-320.jpg)
![func listRun(cmd *cobra.Command, args []string) {
...
w := tabwriter.NewWriter(os.Stdout, 3, 0, 1, ' ', 0)
for _, i := range items {
fmt.Fprintln(w, strconv.Itoa(i.Priority)+"t"+i.Text+"t")
}
w.Flush()
}
CMD/LIST.GO
327](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-327-320.jpg)
![func listRun(cmd *cobra.Command, args []string) {
...
w := tabwriter.NewWriter(os.Stdout, 3, 0, 1, ' ', 0)
for _, i := range items {
fmt.Fprintln(w, strconv.Itoa(i.Priority)+"t"+i.Text+"t")
}
w.Flush()
}
CMD/LIST.GO
328](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-328-320.jpg)
![func listRun(cmd *cobra.Command, args []string) {
...
w := tabwriter.NewWriter(os.Stdout, 3, 0, 1, ' ', 0)
for _, i := range items {
fmt.Fprintln(w, strconv.Itoa(i.Priority)+"t"+i.Text+"t")
}
w.Flush()
}
CMD/LIST.GO
329](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-329-320.jpg)
![func listRun(cmd *cobra.Command, args []string) {
...
w := tabwriter.NewWriter(os.Stdout, 3, 0, 1, ' ', 0)
for _, i := range items {
fmt.Fprintln(w, strconv.Itoa(i.Priority)+"t"+i.Text+"t")
}
w.Flush()
}
CMD/LIST.GO
330](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-330-320.jpg)
![func listRun(cmd *cobra.Command, args []string) {
...
w := tabwriter.NewWriter(os.Stdout, 3, 0, 1, ' ', 0)
for _, i := range items {
fmt.Fprintln(w, i.PrettyP()+"t"+i.Text+"t")
}
w.Flush()
}
CMD/LIST.GO
334](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-334-320.jpg)
![func ReadItems(filename string) ([]Item, error) {
...
for i, _ := range items {
items[i].position = i + 1
}
return items, nil
}
TODO/TODO.GO
340](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-340-320.jpg)
![// ByPri implements sort.Interface for []Item based on
// the Priority & position field.
type ByPri []Item
func (s ByPri) Len() int { return len(s) }
func (s ByPri) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s ByPri) Less(i, j int) bool {
if s[i].Priority == s[j].Priority {
return s[i].position < s[j].position
}
return s[i].Priority < s[j].Priority
}
TODO/TODO.GO
343](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-343-320.jpg)
![// ByPri implements sort.Interface for []Item based on
// the Priority & position field.
type ByPri []Item
func (s ByPri) Len() int { return len(s) }
func (s ByPri) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s ByPri) Less(i, j int) bool {
if s[i].Priority == s[j].Priority {
return s[i].position < s[j].position
}
return s[i].Priority < s[j].Priority
}
TODO/TODO.GO
344](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-344-320.jpg)
![// ByPri implements sort.Interface for []Item based on
// the Priority & position field.
type ByPri []Item
func (s ByPri) Len() int { return len(s) }
func (s ByPri) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s ByPri) Less(i, j int) bool {
if s[i].Priority == s[j].Priority {
return s[i].position < s[j].position
}
return s[i].Priority < s[j].Priority
}
TODO/TODO.GO
345](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-345-320.jpg)
![// ByPri implements sort.Interface for []Item based on
// the Priority & position field.
type ByPri []Item
func (s ByPri) Len() int { return len(s) }
func (s ByPri) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s ByPri) Less(i, j int) bool {
if s[i].Priority == s[j].Priority {
return s[i].position < s[j].position
}
return s[i].Priority < s[j].Priority
}
TODO/TODO.GO
346](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-346-320.jpg)
![// ByPri implements sort.Interface for []Item based on
// the Priority & position field.
type ByPri []Item
func (s ByPri) Len() int { return len(s) }
func (s ByPri) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s ByPri) Less(i, j int) bool {
if s[i].Priority == s[j].Priority {
return s[i].position < s[j].position
}
return s[i].Priority < s[j].Priority
}
TODO/TODO.GO
347](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-347-320.jpg)
![// ByPri implements sort.Interface for []Item based on
// the Priority & position field.
type ByPri []Item
func (s ByPri) Len() int { return len(s) }
func (s ByPri) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s ByPri) Less(i, j int) bool {
if s[i].Priority == s[j].Priority {
return s[i].position < s[j].position
}
return s[i].Priority < s[j].Priority
}
TODO/TODO.GO
348](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-348-320.jpg)
![func listRun(cmd *cobra.Command, args []string) {
...
sort.Sort(todo.ByPri(items))
w := tabwriter.NewWriter(os.Stdout, 3, 0, 1, ' ', 0)
...
CMD/LIST.GO
349](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-349-320.jpg)
![// doneCmd represents the done command
var doneCmd = &cobra.Command{
Use: "done",
Aliases: []string{"do"},
Short: "Mark Item as Done",
Run: doneRun,
}
CMD/DONE.GO
354](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-354-320.jpg)
![func doneRun(cmd *cobra.Command, args []string) {
items, err := todo.ReadItems(dataFile)
i, err := strconv.Atoi(args[0])
if err != nil {
log.Fatalln(args[0], "is not a valid labeln", err)
}
...
CMD/DONE.GO
358
Break out still](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-358-320.jpg)
![func doneRun(cmd *cobra.Command, args []string) {
...
if i > 0 && i < len(items) {
items[i-1].Done = true
fmt.Printf("%q %vn", items[i-1].Text, "marked done")
sort.Sort(todo.ByPri(items))
todo.SaveItems(dataFile, items)
} else {
log.Println(i, "doesn't match any items")
}
}
CMD/DONE.GO
359
Break out slide](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-359-320.jpg)
![func (s ByPri) Less(i, j int) bool {
if s[i].Done == s[j].Done {
if s[i].Priority == s[j].Priority {
return s[i].position < s[j].position
}
return s[i].Priority < s[j].Priority
}
return !s[i].Done
}
TODO/TODO.GO
366](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-366-320.jpg)
![func listRun(cmd *cobra.Command, args []string) {
...
for _, i := range items {
if i.Done == doneOpt {
fmt.Fprintln(w, i.Label()...)
}
}
CMD/LIST.GO
373](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-373-320.jpg)
![func listRun(cmd *cobra.Command, args []string) {
...
for _, i := range items {
if allOpt || i.Done == doneOpt {
fmt.Fprintln(w, i.Label()...)
}
}
CMD/LIST.GO
378](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-378-320.jpg)
![func addRun(cmd *cobra.Command, args []string) {
items, err := todo.ReadItems(dataFile))
...
if err := todo.SaveItems(dataFile), items); err != nil {
CMD/ADD.GO
393](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-393-320.jpg)
![func addRun(cmd *cobra.Command, args []string) {
items, err := todo.ReadItems(viper.GetString("datafile"))
...
if err := todo.SaveItems(viper.GetString("datafile"), items);
err != nil {
CMD/ADD.GO
394](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-394-320.jpg)
![func doneRun(cmd *cobra.Command, args []string) {
...
items, err := todo.ReadItems(viper.GetString("datafile"))
...
todo.SaveItems(viper.GetString("datafile"), items)
CMD/DONE.GO
395](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-395-320.jpg)
![func listRun(cmd *cobra.Command, args []string) {
items, err := todo.ReadItems(viper.GetString("datafile"))
...
CMD/LIST.GO
396](https://image.slidesharecdn.com/buildinganappworkshop-160516181904/85/Building-Awesome-CLI-apps-in-Go-396-320.jpg)
Building Awesome CLI apps in Go
- 1. BUILDING AN AWESOME CLI APP IN GO 1
- 2. 2
- 3. ASHLEY MAC •Dev Advocate at Rackspace •Go newbie •Slightly sarcastic 3
- 4. –Ashley Mac “I have no idea what i’m doing” 4
- 5. SPF13 •Willfully Unemployed •Builds Cool Things With Go AKA Gopher •Irritatingly Specific 5
- 6. –Steve “I Kinda Know What I'm Doing” 6
- 7. MAKE SURE YOU HAVE GO INSTALLED AND WORKING + AN EDITOR 7
- 8. UX OF CLI 8
- 13. – Rob Pike “Many UNIX programs do quite trivial things in isolation, but, combined with other programs, become general and useful tools.” 13
- 14. – Doug McIlroy “The manual page, which really used to be a manual page, is now a small volume, with a thousand options” 14
- 15. POSIx + GNU 15
- 16. COMMANDS 16
- 19. › ls › cp › cat › cd list copy concatenate change directory ABBREVIATED 19
- 20. › ls › cp › cat › cd SHORT 20 Short Clear &
- 21. › ls CONTExT 21 operates in current Directory
- 23. › ls HAS A LANGUAGE 23 List the contents of the directory I'm in
- 24. › ls › rm › zip › find COMMANDS 24 Verbs
- 26. ARGS 26
- 28. › rm [file] › cp [file] [newfile] c:copy [file] [newfile] INPUT 28
- 29. > rm [file] ... [fileN] MANY INPUTS 29 Arg0 Argn
- 30. > cp [file] [newfile] ORDER MATTERS 30 From To
- 31. > cp [file] [newfile] SEPARATED 31 Space separates
- 33. > cp [file] [newfile] DIRECT OBJECT 33 Verb Noun Noun
- 34. > cp [file] [newfile] IS PROUNCABLE 34 Copy this file to here
- 35. OPTIONS 35
- 36. FLAGS 36
- 37. › rm [options] [file] c:del [options] [file] MODIFY ACTIONS 37
- 38. › rm -f badfile.txt SEPARATORS 38 Space separates
- 42. -f == --force SHORT VS LONG 42 Common Options shortened
- 43. › rm -r -f rm -rf STACKABLE 43 Short options stack
- 45. › rm --force [file] ADVERB 45 Verb Adverb Noun
- 46. › rm --force [file] PRONOUNCEABLE 46 Forcefully remove this file
- 47. › rm --force [file] PRONOUNCEABLE 47 remove this file with Force
- 48. › ls --color /home/spf13 FLAG INPUT 48 Verb Adverb Noun
- 49. › ls --color /home/spf13 PRONOUNCEABLE 49 Colorfully list my home directory
- 50. › ls -a MODIFY BEHAVIOR 50
- 51. › ls -a MODIFY BEHAVIOR 51 List all the things
- 54. ADVERBS ANSWER •How? •In what way? •When? •Where? •To what extent? 54
- 55. › ls -a MODIFY BEHAVIOR 55 List completely to what extent?
- 56. › ls --width=40 IMPUTABLE 56 Input to what extent?
- 57. › ls --width 40 IMPUTABLE 57 Input to what extent?
- 58. › ls --width 40 PREPOSITION 58 Verb Preposition Obj
- 59. › ls --width 40 PRONOUNCEABLE 59 list the directory with a width of 40 cols
- 60. PREP PHRASE = ADVERB •consists of a preposition and its object •acts as an adverb •"Speaking at OSCON" 60
- 63. › tar -xcvf FLAG = ACTION 63
- 64. › tar First option must be a mode specifier: -c Create -r Add/Replace -t List -u Update -x Extract FLAG = ACTION 64
- 67. Extract: tar -x [options] -k Keep existing files -m Don't restore mod times FLAGS HAVING SUB FLAGS 67
- 68. Create: tar -c [options] -z, -j, -J, --lzma Compress archive with gzip/ bzip2/xz/lzma FLAGS HAVING SUB FLAGS 68
- 70. ls [options] -S sort by file size -t sort by modification time -U do not sort ... INCOMPATIBLE FLAGS 70
- 71. ls -StU INCOMPATIBLE FLAGS 71 What should this do?
- 73. DOUBLE FLAGS 73
- 74. › git pull --stat --no-stat FLAG --NO-FLAG 74
- 75. › git pull --stat › git pull --stat=false BETTER 75
- 76. CLI APPS 76
- 77. › httpd › vi › emacs › git CLI APPS 77 Noun
- 78. APPS •Launch something •Do more than one thing •Collection of commands 78
- 79. SUB COMMANDS 79
- 80. › svn add › brew install › npm search › apt-get upgrade › git clone SUB COMMANDS 80
- 81. SUB COMMANDS •CLI apps do multiple things •Apps are groups of commands •(sub) Commands have flags & args •All rules still apply 81
- 82. › brew fetch -v hugo ExPANDED RESOURCES 82 Cmd ArgApp Flag
- 83. › brew install hugo NOUN 83 Verb ObjectNoun
- 84. › brew install hugo PRONOUNCABLE 84 Brew, install hugo
- 85. › brew fetch -v hugo PRONOUNCABLE 85 Verb Object Noun adVerb
- 86. › brew fetch -v hugo PRONOUNCABLE 86 Brew, verbosely fetch hugo
- 88. MY ExPERIENCE 88
- 89. GOPATH AND SETUP •You WILL store your code in a GitHub user folder (example: $GOPATH/src/ github.com/username/helloworld) •This was a pain in the ass •I was comfortable with /code /dev/ or /projects 89
- 90. GOPATH AND SETUP •By Storing code on github, I was able to share my many problems •Going from “I’m working on this” to “let’s collaborate” 90
- 91. GOPATH •The Go toolset uses an environment variable called GOPATH to find Go source code. •You can set GOPATH to anything you want, but things will be easier if it’s set in your home directory. 91
- 92. Windows: c: setx GOPATH %USERPROFILE% OS X: ❯ echo 'export GOPATH=$HOMEn' >> ~/.bash_profile Close the terminal, reopen it, and type the following: ❯ echo $GOPATH GO PATH 92
- 93. GOPATH AND SETUP •Typing go get github.com/user/ project will download and build a project. 93
- 94. EDITORS •No IDE needed - any text editor will do. •helpful features like autocomplete and format & import on-save •If you’re not sure what to use, I recommend Atom — It’s free, cross- platform, and easy to install. 94
- 95. PLUGINS •Atom: https://github.com/joefitzgerald/go-plus •Vim: https://github.com/fatih/vim-go •included in http://vim.spf13.com/ •IntelliJ: https://plugins.jetbrains.com/plugin/?id=5047 •Full list: https://github.com/golang/go/wiki/ IDEsAndTextEditorPlugins 95
- 96. YOU DON’T NEED A FRAMEWORK! •The standard library has tons! •Web server •Templates •Database •etc.. 96
- 97. YOU DON’T NEED A FRAMEWORK! •Many Packages work well together •Very modular & Composable 97
- 98. STANDARD LIBRARY Let’s be honest, you don’t want to write everything from scratch so most programming depends on your ability to interface with existing libraries. i.e. packages. Here are a few core packages you should know about; •Strings •Input/Output (io/ioutil) •Errors •fmt 98 • Containers and Sort • path/filepath • HTTP (net/http) • math/rand
- 99. GO 99
- 100. STATICALLY TYPED 100
- 101. STRONGLY TYPED 101
- 102. COMPILED 102
- 103. MEMORY MANAGED 103
- 105. OPEN SOURCE105
- 106. CROSS PLATFORM 106
- 107. LANGUAGE DESIGN 107
- 108. 108 •Ken Thompson (B,C, Unix, UTF-8) •Rob Pike (Unix, UTF-8) •Robert Griesmier (Hotspot, JVM, V8)
- 109. MAJOR INFLUENCES •C & derivatives •Pascal & derivatives •CSP 109
- 111. SPEC •Java Spec : 670 pages •YAML Spec : 84 pages •Go Spec : 82 pages 111
- 113. BRACES 113 Fail
- 114. BRACES Compile Eror 114 Compile Error /tmp/sandbox826898458/main.go:6: syntax error: unexpected semicolon or newline before {
- 116. VARIABLES 116 Fail
- 117. VARIABLES 117 Error /tmp/sandbox473116179/main.go:6: one declared and not used /tmp/ sandbox473116179/main.go:7: two declared and not used /tmp/ sandbox473116179/main.go:8: three declared and not used
- 119. CLASSES ( * SHOCKED EXPRESSION *)119
- 120. OBJECTS 120
- 121. COMPLExITY 121
- 122. TYPES 122
- 124. NUMBERS •Integers (numbers without a decimal) •Floating-Point Numbers (numbers that contain a decimal) • int, int8-64, uint, uint8-64, float32,64 124
- 125. STRINGS •A string is a sequence of characters •Go strings are immutable •Go strings are made up of individual bytes (Usually one for each character) 125
- 127. type person struct { name string age int } STRUCT 127
- 128. ARRAY •An array is an ordered sequence of elements of a single type •Fixed length •Arrays are indexed starting from 0 128
- 129. SLICE •Segment of an array •Dynamic length •Can be used without thinking about array underneath 129
- 130. MAP •Unordered collection of key-value pairs •Similar to associative arrays, hash tables, and dictionaries •Dynamic Length 130
- 131. SOME OTHER TYPES 131
- 132. FUNCTION •Function is a type •First class citizen in Go •Can have multiple input values •Can have multiple return values 132
- 133. POINTERS •Reference a location in memory where a value is stored •Represented using '*' •Memory location referenced using '&' 133
- 134. DEFINE YOUR OWN TYPES •Composed of other types •Not aliases 134
- 135. METHOD •Function defined on a type 135
- 136. TOOLING 136
- 137. GO HELP The Go toolset has many different commands and subcommands. You can pull up a list by typing: go help You now have everything you need to get started 137
- 138. GO FMT •Formats your go code for you •Awesome to do "on save" •End of all stylistic debates 138
- 139. GO TEST Writing code isn’t easy and humans make mistakes so testing is really important, luckily, Go includes a program that makes writing tests easier: go test Fun Fact: The Go compiler knows to ignore code in files ending with _test.go 139
- 140. CLOSING THOUGHTS 140
- 141. I THINK GO IS AWESOME 141
- 143. COMPILATION IS VERY FAST (USUALLY A SECOND OR TWO)143
- 145. RESOURCES •Getting Started, official golang page — https://golang.org/doc/ •Parse’s move from Ruby to Golang — http://blog.parse.com/ learn/how-we-moved-our-api-from-ruby-to-go-and-saved-our-sanity/ •Tutorial — Creating a Wiki — https://golang.org/doc/articles/ wiki/ (this was the first big tutorial that got me to build something useful, take this one slow to get a grasps on its concepts) •Golang — Concurrency is not Parallelism (Rob Pike), this video I found super informative about go’s concurency and got me excited to keep coding in Golang — https://youtu.be/cN_DpYBzKso 145
- 147. 147
- 152. SHOCKING AMOUNT OF TODO APPS 152
- 153. LET'S MAKE A BUNCH MORE 153
- 155. FEATURES 155
- 156. FEATURES •Add Todo •List Todos •Mark "done" •Search/Filter •Priorities •Archive •Edit •Create Dates •Due Dates •Tags •Projects 156
- 157. INTERFACE DESIGN 157
- 158. ADDING 158
- 159. › tri add "Add Priorities" ADD 159
- 160. › tri add Add Priorities ADD 160
- 161. › tri add "Add Priorities" ADD 161 Verb Object Noun
- 162. › tri add "Add Multi Todo Support" "Consider usage behaviors" ADD 162
- 163. PRIORITY 163
- 164. › tri add -p1 "Add listing" ADD WITH PRIORITY 164
- 165. › tri add -p1 "Add listing" ADD WITH PRIORITY 165 Verb Object Noun adVerb
- 166. › tri add -p1 "Add listing" PRONOUNCEABLE 166 Tri, add "Add listing" Todo with a pri of 1
- 167. › tri add "Add listing P:1" ALTERNATE SYNTAx 167
- 168. CONSIDERATIONS •What priority system to use? •Numeric •Alpha •High, Middle, Low •What's the default priority? 168
- 169. MY TODO •High, Middle, Low •H=1, L=3, M/_=2 •Default is 2 169
- 170. LISTING 170
- 171. › tri ls LISTING 171
- 173. › tri LISTING 173
- 174. › tri list (1) Add Listing Consider usage behaviors Add Multi Todo Support Add Priorities LISTING OUTPUT 174
- 175. › tri list (1) Add Listing Add Priorities Add Multi Todo Support Consider usage behaviors LISTING OUTPUT 175
- 176. › tri list (H) Add Listing Consider usage behaviors Add Priorities (L) Add Multi Todo Support LISTING OUTPUT 176
- 177. › tri list (H) Add Listing Consider usage behaviors Add Priorities (L) Add Multi Todo Support LISTING OUTPUT 177
- 178. › tri list 1. (H) Add Listing 2. Consider usage behaviors 3. Add Priorities 4. (L) Add Multi Todo Support LISTING OUTPUT 178
- 179. FILTERING 179
- 180. › tri list done TOKENS 180
- 181. › tri list -p1 FLAGS 181
- 182. › tri list -p1 › tri list --due June › tri list --created 12/15 › tri list --done -p1 FILTER BY PROPERTY 182
- 183. › tri list -p2 2. Consider usage behaviors 3. Add Priorities FILTER BY PRIORITY 183
- 184. › tri list "Add" 1. (H) Add Listing 3. Add Priorities 4. (L) Add Multi Todo Support SEARCHING 184
- 185. › tri list "Add" "Pri" 3. Add Priorities SEARCHING 185
- 186. UPDATING 186
- 187. › tri list 1. (H) Add Listing 2. Consider usage behaviors 3. Add Priorities 4. (L) Add Multi Todo Support LISTING OUTPUT 187
- 188. › tri done 2 COMPLETING 188
- 189. › tri edit 1 "Improve Listing" EDITING 189
- 190. › tri edit 1 -p2 › tri edit 2 --due 05/13/15 › tri edit 3 --created 12/15 EDITING 190
- 191. › tri edit 1 -p2 › tri list -p2 › tri edit 3 --created 12/15 › tri list --created 12/15 CONSISTENCY 191
- 192. › tri edit 1 2 3 -p2 BATCH EDIT? 192
- 194. COBRA 194
- 195. •A CLI Command Framework •A tool to generate CLI apps & commands •Powers Kubernetes, Dropbox, Git Lfs, CoreOS, Docker, Delve ... 195
- 196. › go get -u github.com/spf13/cobra/cobra GET & INSTALL COBRA 196
- 197. › cobra Cobra is a Cli library for Go that empowers applications. This application is a tool to generate the needed files to quickly create a Cobra application. Usage: cobra [command] Available Commands: add Add a command to a Cobra Application COBRA 197
- 199. › cobra init github.com/<handle>/tri -a "<Your Name>" COBRA INIT 199 Replace with your url, project name & Name
- 200. › cobra init ... Your Cobra application is ready at /Users/spf13/gopath/src/ github.com/spf13/tri COBRA 200
- 201. › cd $GOPATH/src/ github.com/<name>/tri CD TO PROJECT 201 Replace with your url, project name & Name
- 202. › tree . ├── LICENSE ├── cmd │ └── root.go └── main.go LOOK AT YOUR PROJECT 202
- 203. › go build › ./tri A longer description that spans multiple lines and likely contains examples and usage of using your application. For example... BUILD & RUN IT 203
- 204. YOU'VE JUST CREATED YOUR 1ST GO APP 204
- 205. IT'S ALL UPHILL FROM HERE 205
- 207. OPEN THE PROJECT IN AN EDITOR 207
- 208. 208 LiteIDE
- 209. 209
- 212. package cmd import ( "fmt" "os" "github.com/spf13/cobra" "github.com/spf13/viper" ) CMD/ROOT.GO 212
- 213. package cmd import ( "fmt" "os" "github.com/spf13/cobra" "github.com/spf13/viper" ) CMD/ROOT.GO 213 Notice package name Matches Dir
- 214. // This represents the base command when called without any subcommands var RootCmd = &cobra.Command{ Use: "tri", Short: "A brief description of your application", Long: `A longer description that spans multiple lines and likely ... application.`, } CMD/ROOT.GO 214
- 215. // This represents the base command when called without any subcommands var RootCmd = &cobra.Command{ Use: "tri", Short: "Tri is a todo application", Long: `Tri will help you get more done in less time. It's designed to be as simple as possible to help you accomplish your goals.`, } CMD/ROOT.GO 215
- 216. var RootCmd = &cobra.Command{ Use: "tri", ... CMD/ROOT.GO 216 Package level variable & Exported
- 217. MAIN 217
- 218. MAIN MAIN MAIN •Go programs are all about "main" •main.go (convention) •main package •main() 218
- 219. package main import "github.com/<yours>/tri/cmd" func main() { cmd.Execute() } MAIN.GO 219
- 220. package main import "github.com/<yours>/tri/cmd" func main() { cmd.Execute() } MAIN.GO 220 Package Name
- 221. package main import "github.com/<yours>/tri/cmd" func main() { cmd.Execute() } MAIN.GO 221 Function Name
- 222. func Execute() { if err := RootCmd.Execute(); err != nil { fmt.Println(err) os.Exit(-1) } } CMD/ROOT.GO 222 Package level variable
- 223. >go run main.go Tri will help you get more done in less time. It's designed to be as simple as possible to help you accomplish your goals. RUN IT 223
- 224. 3. CREATING OUR ADD COMMAND 224
- 225. ADD "ADD" 225
- 226. > cd $GOPATH/src/ github.com/spf13/tri CD TO PROJECT 226 Replace with your url, project name & Name
- 227. > cobra add add add created at $GOPATH/src/ github.com/spf13/tri/cmd/ add.go COBRA ADD ADD 227
- 228. > go run main.go add add called RUN "ADD" 228 Bill wants me to replace go run with go build ./tri
- 229. MAKE "ADD" ADD229
- 231. var addCmd = &cobra.Command{ Use: "add", Short: "A brief description of your command", Long: `A longer description that spans multiple lines and likely...`, Run: func(cmd *cobra.Command, args []string) { // TODO: Work your own magic here fmt.Println("add called") }, } CMD/ADD.GO 231
- 232. var addCmd = &cobra.Command{ Use: "add", Short: "Add a new todo", Long: `Add will create a new todo item to the list`, Run: func(cmd *cobra.Command, args []string) { // TODO: Work your own magic here fmt.Println("add called") }, } CMD/ADD.GO 232
- 233. func addRun(cmd *cobra.Command, args []string){ fmt.Println("add called") } CMD/ADD.GO 233
- 234. var addCmd = &cobra.Command{ Use: "add", Short: "Add a new todo", Long: `Add will create a new todo item to the list`, Run: addRun, } CMD/ADD.GO 234
- 235. func addRun(cmd *cobra.Command, args []string) { for _, x := range args { fmt.Println(x) } } CMD/ADD.GO 235
- 236. FOR x, Y := RANGE •Provides a way to iterate over an array, slice, string, map, or channel. •Like Foreach or Each in other languages •x is index/key, y is value •_ allows you to ignore naming variables 236
- 238. INIT() •Special function •Called after package variable declarations •Called prior to main.main() •Each package may have multiple init() •init() order un-guaranteed 238
- 239. > go run main.go add "one two" three one two three RUNNING ADD 239
- 240. 4. CREATING OUR DATA MODEL 240
- 243. package todo type Item struct { Text string } TODO/TODO.GO 243
- 244. NAMED TYPES •Can be any known type (struct, string, int, slice, a new type you’ve declared, etc) •Methods can be declared on it •Not an alias - Explicit type 244
- 247. func addRun(...) { items := []todo.Item{} for _, x := range args { items = append(items, todo.Item{Text:x}) } fmt.Println(items) } CMD/ADD.GO 247
- 248. func addRun(...) { items := []todo.Item{} for _, x := range args { items = append(items, todo.Item{Text:x}) } fmt.Println(items) } CMD/ADD.GO 248
- 249. APPEND •Append adds new values to a slice •Append will grow a slice as needed 249
- 250. func addRun(...) { items := []todo.Item{} for _, x := range args { items = append(items, todo.Item{Text:x}) } fmt.Println(items) } CMD/ADD.GO 250
- 251. func addRun(...) { items := []todo.Item{} for _, x := range args { items = append(items, todo.Item{Text:x}) } fmt.Println(items) } CMD/ADD.GO 251
- 252. >go run main.go add "one two" three [{one two} {three}] GO RUN 252
- 253. func addRun(...) { var items = []todo.Item{} for _,x := range args { items = append(items, todo.Item{Text:x}) } fmt.Printf("%#vn", items) } CMD/ADD.GO 253
- 254. >go run main.go add "one two" three []todo.Item{todo.Item{Text: "one two"}, todo.Item{Text:"three"}} GO RUN 254
- 256. SAVING DATA 256
- 257. func SaveItems(filename string, items []Item) error { return nil } TODO/TODO.GO 257
- 258. JSON 258
- 260. func SaveItems(filename string, items []Item) error { b, err := json.Marshal(items) if err != nil { return err } fmt.Println(string(b)) return nil } TODO/TODO.GO 260
- 261. func SaveItems(filename string, items []Item) error { b, err := json.Marshal(items) if err != nil { return err } fmt.Println(string(b)) return nil } TODO/TODO.GO 261
- 262. func SaveItems(filename string, items []Item) error { b, err := json.Marshal(items) if err != nil { return err } fmt.Println(string(b)) return nil } TODO/TODO.GO 262
- 263. ERROR HANDLING •Errors are not exceptional, they are just values •No exceptions in Go •Errors should be handled when they occur 263
- 264. ( DON’T) PANIC •Only use when: 1. You want to shut down your program AND 2. You need a stack trace •Packages should never call Panic (only applications) •Do not use as pseudo-exception handling •Only recover a panic if you know you can properly recover from it 264
- 265. func SaveItems(filename string, items []Item) error { b, err := json.Marshal(items) if err != nil { return err } fmt.Println(string(b)) return nil } TODO/TODO.GO 265
- 266. func addRun(cmd *cobra.Command, args []string) { var items = []todo.Item{} for _, x := range args { items = append(items, todo.Item{Text: x}) } todo.SaveItems("x", items) } CMD/ADD.GO 266
- 267. >go run main.go add "one two" three [{"Text":"one two"}, {"Text":"three"}] CHECK JSON CREATION 267
- 268. WRITING TO FILES268
- 270. func SaveItems(filename string, items []Item) error { ... err = ioutil.WriteFile(filename, b, 0644) if err != nil { return err } return nil } TODO/TODO.GO 270
- 271. func addRun(cmd *cobra.Command, args []string) { var items = []todo.Item{} for _, x := range args { items = append(items, todo.Item{Text: x}) } err := todo.SaveItems("/Users/spf13/.tridos.json", items); if err != nil { fmt.Errorf("%v", err) } } CMD/ADD.GO 271
- 272. › go run main.go add "one two" three › cat ~/.tridos.json [{"Text":"one two"}, {"Text":"three"}] CHECK FILE CREATION 272
- 273. READING DATA 273
- 274. func ReadItems(filename string) ([]Item, error) { return []Item{}, nil } TODO/TODO.GO 274
- 275. func ReadItems(filename string) ([]Item, error) { return []Item{}, nil } TODO/TODO.GO 275
- 276. func ReadItems(filename string) ([]Item, error) { b, err := ioutil.ReadFile(filename) if err != nil { return []Item{}, err } ... TODO/TODO.GO 276
- 277. func ReadItems(filename string) ([]Item, error) { b, err := ioutil.ReadFile(filename) if err != nil { return []Item{}, err } ... TODO/TODO.GO 277
- 278. func ReadItems(filename string) ([]Item, error) { ... var items []Item if err := json.Unmarshal(b, &items); err != nil { return []Item{}, err } return items, nil } TODO/TODO.GO 278
- 279. func ReadItems(filename string) ([]Item, error) { ... var items []Item if err := json.Unmarshal(b, &items); err != nil { return []Item{}, err } return items, nil } TODO/TODO.GO 279
- 280. func ReadItems(filename string) ([]Item, error) { ... var items []Item if err := json.Unmarshal(b, &items); err != nil { return []Item{}, err } return items, nil } TODO/TODO.GO 280
- 281. func ReadItems(filename string) ([]Item, error) { ... var items []Item if err := json.Unmarshal(b, &items); err != nil { return []Item{}, err } return items, nil } TODO/TODO.GO 281
- 282. func ReadItems(filename string) ([]Item, error) { ... var items []Item if err := json.Unmarshal(b, &items); err != nil { return []Item{}, err } return items, nil } TODO/TODO.GO 282
- 283. LIST COMMAND 283
- 284. › cobra add list list created at $GOPATH/ src/github.com/spf13/tri/ cmd/list.go ADD LIST COMMAND 284
- 285. Run: func(cmd *cobra.Command, args []string) { items, err := todo.ReadItems("/Users/ spf13/.tridos.json") if err != nil { log.Printf("%v", err) } fmt.Println(items) }, CMD/LIST.GO 285
- 286. Run: func(cmd *cobra.Command, args []string) { items, err := todo.ReadItems("/Users/ spf13/.tridos.json") if err != nil { log.Printf("%v", err) } fmt.Println(items) }, CMD/LIST.GO 286
- 287. Run: func(cmd *cobra.Command, args []string) { items, err := todo.ReadItems("/Users/ spf13/.tridos.json") if err != nil { log.Printf("%v", err) } fmt.Println(items) }, CMD/LIST.GO 287
- 288. › go run main.go list [{one two} {three}] RUN LIST 288
- 289. func addRun(cmd *cobra.Command, args []string) { var items = []todo.Item{} for _, x := range args { items = append(items, todo.Item{Text: x}) } ... CMD/ADD.GO 289
- 290. func addRun(cmd *cobra.Command, args []string) { items, err := todo.ReadItems("/Users/spf13/.tridos.json") if err != nil { log.Printf("%v", err) } for _, x := range args { items = append(items, todo.Item{Text: x}) } ... CMD/ADD.GO 290
- 291. 6. ADDING ROOT (GLOBAL) FLAGS 291
- 292. USING $HOME 292
- 293. › go get github.com/ mitchellh/go-homedir GO GET 293
- 296. func init() { // Here you will define your flags and configuration settings // Cobra supports Persistent Flags which if defined here will be global for your application home, err := homedir.Dir() if err != nil { log.Println("Unable to detect home directory. Please set data file using --datafile.") } ... CMD/ROOT.GO 296
- 297. ADDING A FLAG297
- 298. func init() { ... RootCmd.PersistentFlags().StringVar(&dataFile, "datafile", home+string(os.PathSeparator)+".tridos.json", "data file to store todos") ... CMD/ROOT.GO 298
- 299. func init() { ... RootCmd.PersistentFlags().StringVar(&dataFile, "datafile", home+string(os.PathSeparator)+".tridos.json", "data file to store todos") CMD/ROOT.GO 299
- 300. func init() { ... RootCmd.PersistentFlags().StringVar(&dataFile, "datafile", home+string(os.PathSeparator)+".tridos.json", "data file to store todos") CMD/ROOT.GO 300
- 301. func init() { ... RootCmd.PersistentFlags().StringVar(&dataFile, "datafile", home+string(os.PathSeparator)+".tridos.json", "data file to store todos") CMD/ROOT.GO 301
- 302. items, err := todo.ReadItems(dataFile) ... err := todo.SaveItems(dataFile, items) CMD/ADD.GO 302
- 303. items, err := todo.ReadItems(dataFile) CMD/LIST.GO 303
- 304. › go build › ./tri ... Flags: --datafile string data file to store todos (default "/ Users/spf13/.tridos.json") -h, --help help for tri Use "tri [command] --help" for more information about a command. SEE THE FLAG 304
- 305. › go build › ./tri add "Add priorities" --datafile $HOME/.next.json › ./tri list --datafile $HOME/.next.json [{Add priorities}] USE THE FLAG 305
- 307. › go run main.go add "add priorities" "order by priority" ADD SOME TODOS 307
- 309. type Item struct { Text string Priority int } TODO/TODO.GO 309
- 310. VALIDATING INPUT 310
- 311. func (i *Item) SetPriority(pri int) { switch pri { case 1: i.Priority = 1 case 3: i.Priority = 3 default: i.Priority = 2 } } TODO/TODO.GO 311
- 312. func (i *Item) SetPriority(pri int) { switch pri { case 1: i.Priority = 1 case 3: i.Priority = 3 default: i.Priority = 2 } } TODO/TODO.GO 312
- 313. func (i *Item) SetPriority (pri int) { switch pri { case 1: i.Priority = 1 case 3: i.Priority = 3 default: i.Priority = 2 } } TODO/TODO.GO 313
- 314. ADDING FLAG 314
- 315. var priority int ... func init() { RootCmd.AddCommand(addCmd) addCmd.Flags().IntVarP(&priority, "priority", "p", 2, "Priority:1,2,3") ... CMD/ADD.GO 315
- 316. var priority int ... func init() { RootCmd.AddCommand(addCmd) addCmd.Flags().IntVarP(&priority, "priority", "p", 2, "Priority:1,2,3") ... CMD/ADD.GO 316
- 317. › go build › ./tri help add Add will create a new todo item to the list Usage: tri add [flags] Flags: -p, --priority int Priority:1,2,3 (default 2) HELP ADD 317
- 318. SETTING PRIORITY318
- 319. func addRun(cmd *cobra.Command, args []string) { ... for _, x := range args { item := todo.Item{Text: x} item.SetPriority(priority) items = append(items, item) } CMD/ADD.GO 319
- 320. func addRun(cmd *cobra.Command, args []string) { ... for _, x := range args { item := todo.Item{Text: x} item.SetPriority(priority) items = append(items, item) } CMD/ADD.GO 320
- 321. › ./tri add "format list" -p1 › ./tri list [{add priorities 0} {order by priority 0} {format list 1}] ADD WITH PRIORITY 321
- 322. 8. MAKING OUR LIST PRETTY 322
- 324. // listCmd respresents the list command var listCmd = &cobra.Command{ Use: "list", Short: "List the todos", Long: `Listing the todos`, Run: listRun, } func listRun(cmd *cobra.Command, args []string) { ... } CMD/LIST.GO 324
- 325. TAB- WRITER325
- 326. func listRun(cmd *cobra.Command, args []string) { ... w := tabwriter.NewWriter(os.Stdout, 3, 0, 1, ' ', 0) for _, i := range items { fmt.Fprintln(w, strconv.Itoa(i.Priority)+"t"+i.Text+"t") } w.Flush() } CMD/LIST.GO 326
- 327. func listRun(cmd *cobra.Command, args []string) { ... w := tabwriter.NewWriter(os.Stdout, 3, 0, 1, ' ', 0) for _, i := range items { fmt.Fprintln(w, strconv.Itoa(i.Priority)+"t"+i.Text+"t") } w.Flush() } CMD/LIST.GO 327
- 328. func listRun(cmd *cobra.Command, args []string) { ... w := tabwriter.NewWriter(os.Stdout, 3, 0, 1, ' ', 0) for _, i := range items { fmt.Fprintln(w, strconv.Itoa(i.Priority)+"t"+i.Text+"t") } w.Flush() } CMD/LIST.GO 328
- 329. func listRun(cmd *cobra.Command, args []string) { ... w := tabwriter.NewWriter(os.Stdout, 3, 0, 1, ' ', 0) for _, i := range items { fmt.Fprintln(w, strconv.Itoa(i.Priority)+"t"+i.Text+"t") } w.Flush() } CMD/LIST.GO 329
- 330. func listRun(cmd *cobra.Command, args []string) { ... w := tabwriter.NewWriter(os.Stdout, 3, 0, 1, ' ', 0) for _, i := range items { fmt.Fprintln(w, strconv.Itoa(i.Priority)+"t"+i.Text+"t") } w.Flush() } CMD/LIST.GO 330
- 331. › go run main.go list 0 add priorities 0 order by priority 1 format list LIST W/PRIORITY 331
- 333. func (i *Item) PrettyP() string { if i.Priority == 1 { return "(1)" } if i.Priority == 3 { return "(3)" } return " " } TODO/TODO.GO 333
- 334. func listRun(cmd *cobra.Command, args []string) { ... w := tabwriter.NewWriter(os.Stdout, 3, 0, 1, ' ', 0) for _, i := range items { fmt.Fprintln(w, i.PrettyP()+"t"+i.Text+"t") } w.Flush() } CMD/LIST.GO 334
- 335. › go run main.go list add priorities order by priority (1) format list LIST W/PRIORITY 335
- 336. LABELS 336
- 337. type Item struct { Text string Priority int position int } TODO/TODO.GO 337
- 338. type Item struct { Text string Priority int position int } TODO/TODO.GO 338 Notice Lowercase p
- 339. func (i *Item) Label() string { return strconv.Itoa(i.position) + "." } TODO/TODO.GO 339
- 340. func ReadItems(filename string) ([]Item, error) { ... for i, _ := range items { items[i].position = i + 1 } return items, nil } TODO/TODO.GO 340
- 341. › go run main.go list 1. add priorities 2. order by priority 3. (1) format list LIST W/PRIORITY 341
- 342. SORT 342
- 343. // ByPri implements sort.Interface for []Item based on // the Priority & position field. type ByPri []Item func (s ByPri) Len() int { return len(s) } func (s ByPri) Swap(i, j int) { s[i], s[j] = s[j], s[i] } func (s ByPri) Less(i, j int) bool { if s[i].Priority == s[j].Priority { return s[i].position < s[j].position } return s[i].Priority < s[j].Priority } TODO/TODO.GO 343
- 344. // ByPri implements sort.Interface for []Item based on // the Priority & position field. type ByPri []Item func (s ByPri) Len() int { return len(s) } func (s ByPri) Swap(i, j int) { s[i], s[j] = s[j], s[i] } func (s ByPri) Less(i, j int) bool { if s[i].Priority == s[j].Priority { return s[i].position < s[j].position } return s[i].Priority < s[j].Priority } TODO/TODO.GO 344
- 345. // ByPri implements sort.Interface for []Item based on // the Priority & position field. type ByPri []Item func (s ByPri) Len() int { return len(s) } func (s ByPri) Swap(i, j int) { s[i], s[j] = s[j], s[i] } func (s ByPri) Less(i, j int) bool { if s[i].Priority == s[j].Priority { return s[i].position < s[j].position } return s[i].Priority < s[j].Priority } TODO/TODO.GO 345
- 346. // ByPri implements sort.Interface for []Item based on // the Priority & position field. type ByPri []Item func (s ByPri) Len() int { return len(s) } func (s ByPri) Swap(i, j int) { s[i], s[j] = s[j], s[i] } func (s ByPri) Less(i, j int) bool { if s[i].Priority == s[j].Priority { return s[i].position < s[j].position } return s[i].Priority < s[j].Priority } TODO/TODO.GO 346
- 347. // ByPri implements sort.Interface for []Item based on // the Priority & position field. type ByPri []Item func (s ByPri) Len() int { return len(s) } func (s ByPri) Swap(i, j int) { s[i], s[j] = s[j], s[i] } func (s ByPri) Less(i, j int) bool { if s[i].Priority == s[j].Priority { return s[i].position < s[j].position } return s[i].Priority < s[j].Priority } TODO/TODO.GO 347
- 348. // ByPri implements sort.Interface for []Item based on // the Priority & position field. type ByPri []Item func (s ByPri) Len() int { return len(s) } func (s ByPri) Swap(i, j int) { s[i], s[j] = s[j], s[i] } func (s ByPri) Less(i, j int) bool { if s[i].Priority == s[j].Priority { return s[i].position < s[j].position } return s[i].Priority < s[j].Priority } TODO/TODO.GO 348
- 349. func listRun(cmd *cobra.Command, args []string) { ... sort.Sort(todo.ByPri(items)) w := tabwriter.NewWriter(os.Stdout, 3, 0, 1, ' ', 0) ... CMD/LIST.GO 349
- 350. › go run main.go list 3. (1) format list 1. add priorities 2. order by priority LIST W/PRIORITY 350
- 352. ADD DONE 352
- 353. › cobra add done done created at $GOPATH/ src/github.com/spf13/tri/ cmd/done.go COBRA ADD DONE 353
- 354. // doneCmd represents the done command var doneCmd = &cobra.Command{ Use: "done", Aliases: []string{"do"}, Short: "Mark Item as Done", Run: doneRun, } CMD/DONE.GO 354
- 355. ADD .DONE 355
- 356. type Item struct { Text string Priority int position int Done bool } TODO/TODO.GO 356
- 357. TRI DONE SET .DONE 357
- 358. func doneRun(cmd *cobra.Command, args []string) { items, err := todo.ReadItems(dataFile) i, err := strconv.Atoi(args[0]) if err != nil { log.Fatalln(args[0], "is not a valid labeln", err) } ... CMD/DONE.GO 358 Break out still
- 359. func doneRun(cmd *cobra.Command, args []string) { ... if i > 0 && i < len(items) { items[i-1].Done = true fmt.Printf("%q %vn", items[i-1].Text, "marked done") sort.Sort(todo.ByPri(items)) todo.SaveItems(dataFile, items) } else { log.Println(i, "doesn't match any items") } } CMD/DONE.GO 359 Break out slide
- 360. › go run main.go done a 2016/05/14 22:22:03 a is not a valid label strconv.ParseInt: parsing "a": invalid syntax DONE WRONG 360
- 361. › go run main.go done 13 2016/05/14 22:44:06 13 doesn't match any items DONE WRONG 361
- 362. › go run main.go done 1 DONE RIGHT 362
- 363. UPDATE LISTING363
- 364. func (i *Item) PrettyDone() string { if i.Done { return "X" } return "" } TODO/TODO.GO 364
- 365. fmt.Fprintln(w, i.Label() +"t"+i.PrettyDone() +"t"+i.PrettyP() +"t"+i.Text+"t") CMD/LIST.GO 365
- 366. func (s ByPri) Less(i, j int) bool { if s[i].Done == s[j].Done { if s[i].Priority == s[j].Priority { return s[i].position < s[j].position } return s[i].Priority < s[j].Priority } return !s[i].Done } TODO/TODO.GO 366
- 367. › go run main.go list 1. (1) format list 2. X order by priority 3. X add priorities LIST 367
- 368. ADD --DONE FLAG 368
- 369. › go run main.go add "hide done items" ADD NEW TODO 369
- 370. fmt.Fprintln(w, i.Label() +"t"+i.PrettyDone() +"t"+i.PrettyP() +"t"+i.Text+"t") CMD/LIST.GO 370
- 372. func init() { RootCmd.AddCommand(listCmd) listCmd.Flags().BoolVar(&doneOpt, "done", false, "Show 'Done' Todos ") } CMD/LIST.GO 372
- 373. func listRun(cmd *cobra.Command, args []string) { ... for _, i := range items { if i.Done == doneOpt { fmt.Fprintln(w, i.Label()...) } } CMD/LIST.GO 373
- 374. › go run main.go list --done 3. X order by priority 4. X add priorities TRY --DONE 374
- 375. SHOW ALL 375
- 376. var ( doneOpt bool allOpt bool ) CMD/LIST.GO 376
- 377. func init() { ... listCmd.Flags().BoolVar(&allOpt, "all", false, "Show all Todos") } CMD/LIST.GO 377
- 378. func listRun(cmd *cobra.Command, args []string) { ... for _, i := range items { if allOpt || i.Done == doneOpt { fmt.Fprintln(w, i.Label()...) } } CMD/LIST.GO 378
- 379. › go run main.go list --all --done 1. (1) format list 2. hide done items 3. X order by priority 4. X add priorities TRY --ALL 379
- 380. 10. CONFIG380
- 381. ›./tri list --datafile $HOME/Dropbox/Sync/tridos.json ›./tri add "Add config/ENV support" --datafile $HOME/Dropbox/Sync/tridos.json USING DIFFERENT DATA FILE 381
- 382. CONFIG FTW 382
- 383. •A configuration manager •Registry for application settings •Works well with Cobra 383
- 384. VIPER SUPPORTS •YAML, TOML, JSON or HCL •Etcd, Consul •Config LiveReloading •default < KeyVal < config < env < flag •Aliases & Nested values 384
- 385. var cfgFile string func init() { cobra.OnInitialize(initConfig) ... RootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.tri.yaml)") ... CMD/ROOT.GO 385 Already There
- 386. // Read in config file and ENV variables if set. func initConfig() { viper.SetConfigName(".tri") viper.AddConfigPath("$HOME") viper.AutomaticEnv() // If a config file is found, read it in. if err := viper.ReadInConfig(); err == nil { fmt.Println("Using config file:", viper.ConfigFileUsed()) } } CMD/ROOT.GO 386 Already There
- 387. 12 FACTOR APPS 387
- 389. CONFIG IS STUFF THAT VARIES IN DIFFERENT ENVIRONMENTS 389
- 390. CODE IS STUFF THAT STAYS THE SAME EVERYWHERE 390
- 391. THE 12 FACTOR APP STORES CONFIG IN ENV VARS 391
- 392. READ FROM VIPER 392
- 393. func addRun(cmd *cobra.Command, args []string) { items, err := todo.ReadItems(dataFile)) ... if err := todo.SaveItems(dataFile), items); err != nil { CMD/ADD.GO 393
- 394. func addRun(cmd *cobra.Command, args []string) { items, err := todo.ReadItems(viper.GetString("datafile")) ... if err := todo.SaveItems(viper.GetString("datafile"), items); err != nil { CMD/ADD.GO 394
- 395. func doneRun(cmd *cobra.Command, args []string) { ... items, err := todo.ReadItems(viper.GetString("datafile")) ... todo.SaveItems(viper.GetString("datafile"), items) CMD/DONE.GO 395
- 396. func listRun(cmd *cobra.Command, args []string) { items, err := todo.ReadItems(viper.GetString("datafile")) ... CMD/LIST.GO 396
- 397. ENV 397
- 398. ›./tri list --datafile $HOME/Dropbox/Sync/tridos.json ›./tri add "Add config/ENV support" --datafile $HOME/Dropbox/Sync/tridos.json USING DIFFERENT DATA FILE 398
- 399. › DATAFILE=$HOME/Dropbox/Sync/trido.json ./tri list › DATAFILE=$HOME/Dropbox/Sync/trido.json ./tri add "Add config/ENV support" USING ENV 399
- 400. › export DATAFILE=$HOME/Dropbox/Sync/ trido.json › ./tri list 1. Add config/ENV support 2. Add config/ENV support ExPORT FTW 400
- 402. // Read in config file and ENV variables if set. func initConfig() { viper.SetConfigName(".tri") viper.AddConfigPath("$HOME") viper.AutomaticEnv() viper.SetEnvPrefix("tri") // If a config file is found, read it in. if err := viper.ReadInConfig(); err == nil { fmt.Println("Using config file:", viper.ConfigFileUsed()) } CMD/ROOT.GO 402
- 403. › export TRI_DATAFILE=$HOME/Dropbox/ Sync/trido.json › ./tri list 1. Add config/ENV support 2. Add config/ENV support ExPORT FTW 403
- 404. CONFIG FILES 404
- 405. GOOD FOR APPS405
- 406. › echo "datafile: /Users/ spf13/Dropbox/Sync/ trido.json" > $HOME/.tri.yaml CREATE CONFIG FILE 406
- 407. › go run main.go list Using config file: /Users/ spf13/.tri.yaml 1. Add config/ENV support 2. Add config/ENV support USE CONFIG FILE 407
- 410. EDITING 410
- 411. SEARCH 411
- 413. ADDITIONAL RESOURCES •Ashley's Learn to Code Resources •Steve's Blog •Go Girls Who Code 413
- 414. END 414