RESTful API を Chalice で紐解く 〜 Python Serverless Microframework for AWS 〜
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The document describes how to build serverless applications using the Chalice framework. It shows examples of defining routes, path parameters, HTTP methods, and response handling. It also demonstrates configuring features like CORS, API keys, and authorizers. The document explains how Chalice works behind the scenes by examining its core classes and how it matches incoming requests to route functions. It provides links to additional resources about serverless applications on AWS.
![REST API
GET /users HTTP/1.1
{"users": […]}](https://image.slidesharecdn.com/jawsugosakarestfulapiwithchalice20180120-180121114503/85/RESTful-API-Chalice-Python-Serverless-Microframework-for-AWS-12-320.jpg)
![$ chalice deploy
Creating role: chalice-sample-dev
The following execution policy will be used:
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"s3:GetObject"
],
"Resource": ["*"],
"Sid": "40e10c45a..."
},
...
}
Would you like to continue? [Y/n]:](https://image.slidesharecdn.com/jawsugosakarestfulapiwithchalice20180120-180121114503/85/RESTful-API-Chalice-Python-Serverless-Microframework-for-AWS-25-320.jpg)
![$ chalice local
Serving on localhost:8000
$ npm install -g nodemon
$ nodemon --exec "chalice local" --watch *.py
[nodemon] 1.12.5
[nodemon] to restart at any time, enter `rs`
[nodemon] watching: app.py
[nodemon] starting `chalice local`
Serving on localhost:8000
see@ https://qiita.com/TakenoriHirao/items/69f2af5aaf64db77124b](https://image.slidesharecdn.com/jawsugosakarestfulapiwithchalice20180120-180121114503/85/RESTful-API-Chalice-Python-Serverless-Microframework-for-AWS-26-320.jpg)
![# Specify Methods
@app.route('/', methods=['PUT'])
def index_put():
return {"PUT": "/"}](https://image.slidesharecdn.com/jawsugosakarestfulapiwithchalice20180120-180121114503/85/RESTful-API-Chalice-Python-Serverless-Microframework-for-AWS-30-320.jpg)
![@app.route('/res', methods=['GET', 'POST'])
def my_resource():
request = app.current_request
if request.method == 'GET':
return {"GET": "/res"}
elif request.method == 'POST':
return {"POST": "/res"}](https://image.slidesharecdn.com/jawsugosakarestfulapiwithchalice20180120-180121114503/85/RESTful-API-Chalice-Python-Serverless-Microframework-for-AWS-31-320.jpg)
![# Path Params
@app.route('/myresources/{object_name}')
def my_resource_key(object_name):
try:
response = S3.get_object(
Bucket = BUCKET, Key = object_name)
return response['Body'].read()
except ClientError as e:
raise e](https://image.slidesharecdn.com/jawsugosakarestfulapiwithchalice20180120-180121114503/85/RESTful-API-Chalice-Python-Serverless-Microframework-for-AWS-32-320.jpg)
![@app.route('/s3/{bucket_name}/objects')
def objects_of(bucket_name):
try:
response =
S3.list_objects_v2(Bucket=bucket_name,
Prefix = S3_PREFIX)
objects = list(map(lambda x: x["Key"],
response["Contents"]))
return {"objects": objects}
except ClientError as e:
raise ...](https://image.slidesharecdn.com/jawsugosakarestfulapiwithchalice20180120-180121114503/85/RESTful-API-Chalice-Python-Serverless-Microframework-for-AWS-33-320.jpg)
![class Chalice(object):
def route(self, path, **kwargs): #
def _register_view(view_func):
self._add_route(path, view_func, **kwargs)
return view_func
return _register_view
def _add_route(self, path, view_func, **kwargs):
methods = kwargs.pop('methods', ['GET'])
...
for method in methods:
...
entry = RouteEntry(view_func, name,
path, method, api_key_required, content_types, cors,
authorizer)
self.routes[path][method] = entry](https://image.slidesharecdn.com/jawsugosakarestfulapiwithchalice20180120-180121114503/85/RESTful-API-Chalice-Python-Serverless-Microframework-for-AWS-39-320.jpg)
![class Chalice(object):
def __call__(self, event, context): #
resource_path = event.get('requestContext',
{}).get('resourcePath')
http_method = event['requestContext']['httpMethod']
route_entry = self.routes[resource_path][http_method]
view_function = route_entry.view_function
function_args = {name: event['pathParameters'][name]
for name in route_entry.view_args}
...
response = self._get_view_function_response(view_function,
function_args)
response_headers = CaseInsensitiveMapping(response.headers)
...
response = response.to_dict(self.api.binary_types)
return response](https://image.slidesharecdn.com/jawsugosakarestfulapiwithchalice20180120-180121114503/85/RESTful-API-Chalice-Python-Serverless-Microframework-for-AWS-40-320.jpg)
![@app.sns_topic_subscriber("bartender")
def tend(event, context):
message = json.loads(event["Records"][0]["Sns"]["Message"])
context.log(dict(beer="Quadrupel", quantity=message["beer"]))
@app.cloudwatch_event_handler(source=["aws.ecs"])
def monitor_ecs_events(event, context):
message = json.loads(event["Records"][0]["Sns"]["Message"])
context.log("Got an event from ECS: {}".format(message))
@app.s3_event_handler(bucket="myS3bucket",
events=["s3:ObjectCreated:*"], prefix="foo", suffix=".bar")
def monitor_s3(event, context):
message = json.loads(event["Records"][0]["Sns"]["Message"])
context.log("Got an event from S3: {}".format(message))](https://image.slidesharecdn.com/jawsugosakarestfulapiwithchalice20180120-180121114503/85/RESTful-API-Chalice-Python-Serverless-Microframework-for-AWS-47-320.jpg)
RESTful API を Chalice で紐解く 〜 Python Serverless Microframework for AWS 〜
- 6. • • • •
- 15. Auto Scaling group Security group Elastic Load Balancing Instance REST API Amazon DynamoDB Amazon CloudWatch Amazon S3
- 16. Amazon DynamoDB Amazon CloudWatch Amazon API Gateway AWS Lambda Amazon S3
- 18. Lambda.GetFunction(params: {'body': '', 'url': u'https://lambda.us-west-2.amazonaws.com/2015-03-31 IAM.GetRole(params: {'body': {'Action': u'GetRole', 'RoleName': u'helloworld7', 'Version': u'2010- IAM.CreateRole(params: {'body': {'Action': u'CreateRole', 'RoleName': u'helloworld7', 'Version': u IAM.PutRolePolicy(params: {'body': {'Action': u'PutRolePolicy', 'RoleName': u'helloworld7', 'Polic Lambda.CreateFunction(params: (... omitted from logs due to size ...) APIGateway.GetRestApis(params: {'body': '', 'url': u'https://apigateway.us-west-2.amazonaws.com/re APIGateway.CreateRestApi(params: {'body': '{"name": "helloworld7"}', 'url': u'https://apigateway.u APIGateway.GetResources(params: {'body': '', 'url': u'https://apigateway.us-west-2.amazonaws.com/r APIGateway.PutMethod(params: {'body': '{"authorizationType": "NONE"}', 'url': u'https://apigateway APIGateway.PutIntegration(params: {'body': '{"httpMethod": "POST", "requestTemplates": {"applicati APIGateway.PutMethodResponse(params: {'body': '{"responseModels": {"application/json": "Empty"}}', APIGateway.PutIntegrationResponse(params: {'body': '{"responseTemplates": {"application/json": ""} APIGateway.PutMethodResponse(params: {'body': '{"responseModels": {"application/json": "Empty"}}', APIGateway.PutIntegrationResponse(params: {'body': '{"selectionPattern": "ChaliceViewError.*", "re APIGateway.PutMethodResponse(params: {'body': '{"responseModels": {"application/json": "Empty"}}', APIGateway.PutIntegrationResponse(params: {'body': '{"selectionPattern": "BadRequestError.*", "res APIGateway.PutMethodResponse(params: {'body': '{"responseModels": {"application/json": "Empty"}}', APIGateway.PutIntegrationResponse(params: {'body': '{"selectionPattern": "NotFoundError.*", "respo APIGateway.PutMethodResponse(params: {'body': '{"responseModels": {"application/json": "Empty"}}', APIGateway.PutIntegrationResponse(params: {'body': '{"selectionPattern": "UnauthorizedError.*", "r APIGateway.PutMethodResponse(params: {'body': '{"responseModels": {"application/json": "Empty"}}', APIGateway.PutIntegrationResponse(params: {'body': '{"selectionPattern": "ForbiddenError.*", "resp APIGateway.PutMethodResponse(params: {'body': '{"responseModels": {"application/json": "Empty"}}', APIGateway.PutIntegrationResponse(params: {'body': '{"selectionPattern": "ConflictError.*", "respo APIGateway.PutMethodResponse(params: {'body': '{"responseModels": {"application/json": "Empty"}}', APIGateway.PutIntegrationResponse(params: {'body': '{"selectionPattern": "TooManyRequestsError.*", Lambda.GetPolicy(params: {'body': '', 'url': u'https://lambda.us-west-2.amazonaws.com/2015-03-31/f Lambda.AddPermission(params: {'body': '{"Action": "lambda:InvokeFunction", "StatementId": "1e96468 APIGatewayCreateDeployment(params: {'body': '{"stageName": "dev"}', 'url': u'https://apigateway.us API # AWS SAM
- 21. • • • • • • •
- 22. $ pip install chalice $ chalice new-project helloworld && cd helloworld $ cat app.py from chalice import Chalice app = Chalice(app_name="helloworld") @app.route("/") def index(): return {"hello": "world"}
- 23. $ chalice deploy ... https://endpoint/api $ curl https://endpoint/api {"hello": "world"}
- 24. $ git diff from chalice import Chalice +import boto3 app = Chalice(app_name='chalice-sample') +S3 = boto3.client('s3', region_name='us-east-1') @app.route('/') def index(): + S3.get_object(Bucket = BUCKET, Key = key) return {'hello': 'world'}
- 25. $ chalice deploy Creating role: chalice-sample-dev The following execution policy will be used: { "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Action": [ "s3:GetObject" ], "Resource": ["*"], "Sid": "40e10c45a..." }, ... } Would you like to continue? [Y/n]:
- 26. $ chalice local Serving on localhost:8000 $ npm install -g nodemon $ nodemon --exec "chalice local" --watch *.py [nodemon] 1.12.5 [nodemon] to restart at any time, enter `rs` [nodemon] watching: app.py [nodemon] starting `chalice local` Serving on localhost:8000 see@ https://qiita.com/TakenoriHirao/items/69f2af5aaf64db77124b
- 27. • • •
- 29. # Basic Definition @app.route('/') def index(): return {"GET": "/"}
- 30. # Specify Methods @app.route('/', methods=['PUT']) def index_put(): return {"PUT": "/"}
- 31. @app.route('/res', methods=['GET', 'POST']) def my_resource(): request = app.current_request if request.method == 'GET': return {"GET": "/res"} elif request.method == 'POST': return {"POST": "/res"}
- 32. # Path Params @app.route('/myresources/{object_name}') def my_resource_key(object_name): try: response = S3.get_object( Bucket = BUCKET, Key = object_name) return response['Body'].read() except ClientError as e: raise e
- 33. @app.route('/s3/{bucket_name}/objects') def objects_of(bucket_name): try: response = S3.list_objects_v2(Bucket=bucket_name, Prefix = S3_PREFIX) objects = list(map(lambda x: x["Key"], response["Contents"])) return {"objects": objects} except ClientError as e: raise ...
- 34. @app.route('/') def index(): return Response( body = 'hello world!', status_code = 200, headers = {'Content-Type': 'text/plain'} )
- 36. @app.route('/', cors=True, api_key_required=True, authorizer=IAMAuthorizer()) def index(): return "yey" @app.schedule(Rate(1, unit=Rate.HOURS)) def every_hour(event): print(event.to_dict())
- 38. • • • • •
- 39. class Chalice(object): def route(self, path, **kwargs): # def _register_view(view_func): self._add_route(path, view_func, **kwargs) return view_func return _register_view def _add_route(self, path, view_func, **kwargs): methods = kwargs.pop('methods', ['GET']) ... for method in methods: ... entry = RouteEntry(view_func, name, path, method, api_key_required, content_types, cors, authorizer) self.routes[path][method] = entry
- 40. class Chalice(object): def __call__(self, event, context): # resource_path = event.get('requestContext', {}).get('resourcePath') http_method = event['requestContext']['httpMethod'] route_entry = self.routes[resource_path][http_method] view_function = route_entry.view_function function_args = {name: event['pathParameters'][name] for name in route_entry.view_args} ... response = self._get_view_function_response(view_function, function_args) response_headers = CaseInsensitiveMapping(response.headers) ... response = response.to_dict(self.api.binary_types) return response
- 41. class Chalice(object): def _get_view_function_response(self, view_function, function_args): try: response = view_function(**function_args) if not isinstance(response, Response): response = Response(body=response) self._validate_response(response) except ChaliceViewError as e: response = Response(...) except Exception as e: headers = {} if self.debug: ... else: response = Response(..., status_code=500) return response
- 47. @app.sns_topic_subscriber("bartender") def tend(event, context): message = json.loads(event["Records"][0]["Sns"]["Message"]) context.log(dict(beer="Quadrupel", quantity=message["beer"])) @app.cloudwatch_event_handler(source=["aws.ecs"]) def monitor_ecs_events(event, context): message = json.loads(event["Records"][0]["Sns"]["Message"]) context.log("Got an event from ECS: {}".format(message)) @app.s3_event_handler(bucket="myS3bucket", events=["s3:ObjectCreated:*"], prefix="foo", suffix=".bar") def monitor_s3(event, context): message = json.loads(event["Records"][0]["Sns"]["Message"]) context.log("Got an event from S3: {}".format(message))
- 49. • • • • • • •