Going serverless with Chalice and AWS lambda
Published:
The intentions of this post is to host a simple example of chalice from AWS that allows serverless API creation with the use of AWS lambda. You also get auto-generation of IAM policy making it faster to deploy web applications. Chalice expects to pick the AWS credentials from ~/.aws/config
Prerequisites for chalice[AWS Credentials]
If you’ve used AWS API or boto/boto3 for python, you’ve probably already added the credentials in place. Otherwise you could do it as below:
mkdir ~/.aws
touch ~/.aws/config
Contents of the config file
[default]
aws_access_key_id = YOUR_ACCESS_KEY_HERE
aws_secret_access_key = YOUR_SECRET_ACCESS_KEY
region = YOUR_REGION
Installing Chalice
As a good development practice, we should segregate dependencies between various projects and therefore is advised to use virtual environment or some sort.
$ python3 -m venv serverlessenv
$ source serverlessenv/bin/activate
(serverlessenv)$ pip install chalice
Creating simple API with chalice
Chalice comes with command line tool. See what commands are available
(serverlessenv)$ chalice
Usage: chalice [OPTIONS] COMMAND [ARGS]...
Options:
--version Show the version and exit.
--project-dir TEXT The project directory. Defaults to CWD
--debug / --no-debug Print debug logs to stderr.
--help Show this message and exit.
Commands:
delete
deploy
gen-policy
generate-pipeline Generate a cloudformation template for a...
generate-sdk
invoke Invoke the deployed lambda function NAME.
local
logs
new-project
package
url
(serverlessenv)$ chalice new-project
___ _ _ _ _ ___ ___ ___
/ __|| || | /_\ | | |_ _|/ __|| __|
| (__ | __ | / _ \ | |__ | || (__ | _|
\___||_||_|/_/ \_\|____||___|\___||___|
The python serverless microframework for AWS allows
you to quickly create and deploy applications using
Amazon API Gateway and AWS Lambda.
Please enter the project name: basichelloworld
(serverlessenv)$ cd basichelloworld/
(serverlessenv)~/basichelloworld$ ls -a
app.py .chalice .gitignore requirements.txt
Chalice is very simple, somewhat similar to Flask if you come from there.
Auto-generated app.py
from chalice import Chalice
app = Chalice(app_name='basichelloworld')
@app.route('/')
def index():
return {'hello': 'world'}
# The view function above will return {"hello": "world"}
# whenever you make an HTTP GET request to '/'.
#
# Here are a few more examples:
#
# @app.route('/hello/{name}')
# def hello_name(name):
# # '/hello/james' -> {"hello": "james"}
# return {'hello': name}
#
# @app.route('/users', methods=['POST'])
# def create_user():
# # This is the JSON body the user sent in their POST request.
# user_as_json = app.current_request.json_body
# # We'll echo the json body back to the user in a 'user' key.
# return {'user': user_as_json}
#
# See the README documentation for more examples.
#
Running the API locally
(serverlessenv)~/basichelloworld$ chalice local
Serving on 127.0.0.1:8000
(serverlessenv)~/basichelloworld$ curl -X GET http://127.0.0.1:8000
{"hello": "world"}
Going serverless with chalice through AWS lambda
(serverlessenv)~/basichelloworld$ chalice deploy
Creating deployment package.
Updating policy for IAM role: basichelloworld
Creating lambda function: basichelloworld
Creating Rest API
Resources deployed:
- Lambda ARN: arn:aws:lambda:us-east-1:9582857991:function:basichelloworld
- Rest API URL: https://fxcdyzuitc.execute-api.us-east-1.amazonaws.com/api/
(serverlessenv)~/basichelloworld$ curl -X GET https://fxcdyzuitc.execute-api.us-east-1.amazonaws.com/api/
{"hello": "world"}