serverless-step-functions-local-example

Local emulation of AWS Step Functions with serverless framework

This repository is the serverless framework example for local invocation of AWS Step Functions modifying the existing serverless-step-functions-local plugin.

Prerequisites and Installation

• create an AWS profile (for example, test-profile) in ~/.aws/crendential

  [test-profile]
  aws_access_key_id=<Your AWS Access Key ID>
  aws_secret_access_key=<Your AWS Secret Access Key>

• install unbuffer command (Mac OS)

  $ brew install expect

  type unbuffer command.

  $ unbuffer
  
  can't find package Expect
      while executing
  "package require Expect"
      (file "/opt/homebrew/bin/unbuffer" line 6)
  

  If the above error occurs, execute

  $ sudo vi /opt/homebrew/bin/unbuffer

  and replace

  # -*- tcl -*-
  # The next line is executed by /bin/sh, but not tcl \
  exec tclsh "$0" ${1+"$@"}
  
  package require Expect

  with

  #\
  exec expect "$0" ${1+"$@"}

• install aws-sam-cli

  $ brew tap aws/tap
  $ brew install aws-sam-cli

• install serverless framework

  $ npm install -g serverless

• install related package

  $ npm install stepfunctions-localhost serverless-pseudo-parameters serverless-dotenv-plugin serverless-step-functions serverless-step-functions-local serverless-sam
  $ pip install pyyaml

• version

  $ sam --version
  
  SAM CLI, version 1.56.1

  $ npx serverless --version
  
  Framework Core: 2.72.3 (local)
  Plugin: 5.5.4
  SDK: 4.3.2
  Components: 3.18.2

Deployment

First, deploy with serverless framework.

• execute the below command

  $ npx serverless deploy --aws-profile test-profile

Local invocation

• package with serverless framework

  $ npx serverless package --aws-profile test-profile

• export the SAM template and execute the converter (if there is no template.yml)

  $ npx serverless sam export --output ./template.yml
  $ python ./scripts/sam_template_converter/main.py

  cf. https://qiita.com/hayao_k/items/f8c7ad5e35e29d590957 (in Japanese)

• build SAM layer

  $ sam build --use-container LambdaLayer

  if there is an error such as

  Error: PythonPipBuilder:CopySource - [Errno 2] No such file or directory: '/tmp/samcli/source/.serverless/pythonRequirements.zip'

  remove the layer_requirements/.serverless folder and build again:

  $ rm -rf ./layer_requirements/.serverless

• execute two commands below on independent terminals to invoke local Step Functions
  cf. https://kazuhira-r.hatenablog.com/entry/2019/04/23/000355 (in Japanese)

  $ npx serverless stepf offline --aws-profile test-profile

  $ aws stepfunctions --endpoint http://localhost:8083 start-execution --state-machine arn:aws:states:ap-northeast-1:012345678901:stateMachine:StateMachine --name Lambda_local --input ""

• if you want to invoke a single Lambda function,

  $ aws lambda invoke /dev/null \
  --endpoint-url http://localhost:4002 \
  --function-name ServerlessStepFunctionsExampleentrypoint