Chalice REST API Tutorial

[coding-to-music]

Chalice REST API Tutorial

https://aws.github.io/chalice/tutorials/basicrestapi.html

[coding-to-music]

  930  http GET https://pyuve2v4bh.execute-api.us-east-1.amazonaws.com/api/objects/foo3
  931  http GET https://pyuve2v4bh.execute-api.us-east-1.amazonaws.com/api/objects/foo34
  932  echo '{"foo": "bar"}' | http PUT https://pyuve2v4bh.execute-api.us-east-1.amazonaws.com/api/objects/foo34
  933  http GET https://pyuve2v4bh.execute-api.us-east-1.amazonaws.com/api/objects/foo34
  934  chalice deploy
  935  http 'https://pyuve2v4bh.execute-api.us-east-1.amazonaws.com/api/introspect?query1=value1&query2=value2' 'X-TestHeader: Foo'
  936  chalice deploy
  937  http POST https://pyuve2v4bh.execute-api.us-east-1.amazonaws.com/api/ states=WA states=CA --debug
  938  http --form POST https://pyuve2v4bh.execute-api.us-east-1.amazonaws.com/api/ states=WA states=CA --debug
  939  http --form POST https://pyuve2v4bh.execute-api.us-east-1.amazonaws.com/api/ states=WA states=CA 
  940  chalice deploy
  941  http --form POST https://pyuve2v4bh.execute-api.us-east-1.amazonaws.com/api/ states=WA states=CA 
  942  chalice deploy
  943  http https://pyuve2v4bh.execute-api.us-east-1.amazonaws.com/api/
  944  chalice deploy
  945  http https://pyuve2v4bh.execute-api.us-east-1.amazonaws.com/api/
  946  chalice deploy
  947  http https://pyuve2v4bh.execute-api.us-east-1.amazonaws.com/api/
  948  http --form POST https://pyuve2v4bh.execute-api.us-east-1.amazonaws.com/api/ states=WA states=CA 

[coding-to-music]

Deploying with the AWS CDK

https://aws.github.io/chalice/tutorials/cdk.html

https://github.com/coding-to-music/chalice-learning-examples

[coding-to-music]

https://aws.github.io/chalice/tutorials/wsecho.html

Echo Server Example

An echo server is a simple server that echos any message it receives back to the client that sent it.

$ pip install -U chalice
$ chalice new-project echo-server
$ cd echo-server

Our Chalice application will need boto3 as a dependency for both API Gateway to send websocket messages. Let’s add a boto3 to the requirements.txt file:

$ echo "boto3>=1.9.91" > requirements.txt

Now that the requirement has been added. Let’s install it locally since our next script will need it as well:

$ pip install -r requirements.txt

Next replace the contents of the app.py file with the code below.

from boto3.session import Session

from chalice import Chalice
from chalice import WebsocketDisconnectedError

app = Chalice(app_name="echo-server")
app.websocket_api.session = Session()
app.experimental_feature_flags.update([
    'WEBSOCKETS'
])

@app.on_ws_message()
def message(event):
    try:
        app.websocket_api.send(
            connection_id=event.connection_id,
            message=event.body,
        )
    except WebsocketDisconnectedError as e:
        pass  # Disconnected so we can't send the message back.```

chalice deploy

root@docker-ubuntu-s-1vcpu-2gb-nyc1-01:~/ap/chalice-learning/echo-server# chalice deploy
Creating deployment package.
Creating IAM role: echo-server-dev
Creating lambda function: echo-server-dev-websocket_message
Creating websocket api: echo-server-dev-websocket-api
Resources deployed:
  - Lambda ARN: arn:aws:lambda:us-east-1:708090526287:function:echo-server-dev-websocket_message
  - Websocket API URL: wss://ety3nz5cfh.execute-api.us-east-1.amazonaws.com/api/

To test out the echo server we will use the websocket-client package. You install it from PyPI:

root@docker-ubuntu-s-1vcpu-2gb-nyc1-01:~/ap/chalice-learning/echo-server# pip install websocket-client
Collecting websocket-client
  Downloading websocket_client-1.1.0-py2.py3-none-any.whl (68 kB)
     |████████████████████████████████| 68 kB 1.9 MB/s 
Installing collected packages: websocket-client
Successfully installed websocket-client-1.1.0

After deploying the Chalice app the output will contain a URL for connecting to the websocket API labeled: - Websocket API URL:. The websocket-client package installs a command line tool called wsdump.py which can be used to test websocket echo server:

wsdump.py wss://ety3nz5cfh.execute-api.us-east-1.amazonaws.com/api/

root@docker-ubuntu-s-1vcpu-2gb-nyc1-01:~/ap/chalice-learning/echo-server# wsdump.py wss://ety3nz5cfh.execute-api.us-east-1.amazonaws.com/api/
Press Ctrl+C to quit
> foo

< foo
> bar

< bar
> abc

< abc
> ls -l

< ls -l
> root@docker-ubuntu-s-1vcpu-2gb-nyc1-01:~/ap/chalice-learning/echo-server# chalice logs -n websocket_message
root@docker-ubuntu-s-1vcpu-2gb-nyc1-01:~/ap/chalice-learning/echo-server# 
root@docker-ubuntu-s-1vcpu-2gb-nyc1-01:~/ap/chalice-learning/echo-server# chalice delete
Deleting Websocket API: ety3nz5cfh
Deleting function: arn:aws:lambda:us-east-1:708090526287:function:echo-server-dev-websocket_message
Deleting IAM role: echo-server-dev
root@docker-ubuntu-s-1vcpu-2gb-nyc1-01:~/ap/chalice-learning/echo-server#