Fakey Cognito

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Simple fake AWS Cognito API server for development.

✅ Implemented features

• AdminXxx on User Pools API.

Get Started

# run with cargo on port 8080
cargo run &

# or run on docker from ghcr
docker run -p 8080:8080 ghcr.io/naokirin/fakey-cognito:main

# or build and run on docker from repository code
docker build -t fakey-cognito .
docker run -p 8080:8080 fakey-cognito

# request AdminGetUser
curl -X POST http://localhost:8080 \
     -H 'Content-Type:application/x-amz-json-1.1' \
     -H 'X-Amz-Target:AWSCognitoIdentityProviderService.AdminGetUser' \
     -d '{"Username":"${USER_NAME}","UserPoolId":"${USER_POOL_ID}"}'

Prerequisites

• rust >= 1.55.0

OR

• docker >= 19.03

Usage

First read "Get Started".

Configurations

You use configuration with file (YAML).
Default configuration path is /repository_root/config.yml .

Following configuration file format.

ActionName:
  error_type: <force response error type (e.g. InternalFailure)>

...

When use custom path you specify a command line arguments.

cargo run -- --config /path/to/config.yml

Response templates

Fackey-cognito returns simple response by default.
It also returns rendering templates if you need custom responses.

Default template path is /repository_root/templates/**/*.json .
Template file name is a action name and a directory is user_pools, user_pools_auth.

You can use request parameters in template.

Example for template file (e.g.user_pools/AdminGetDevice.json).

{
   "Device": { 
      "DeviceAttributes": [ 
         { 
            "Name": "DeviceName",
            "Value": "DeviceValue"
         }
      ],
      "DeviceCreateDate": {{ now() | date(format="%Y%m%d%H%M%S" )}},
      "DeviceKey": "{{DeviceKey}}",
      "DeviceLastAuthenticatedDate": {{ now() | date(format="%Y%m%d%H%M%S" )}},
      "DeviceLastModifiedDate": {{ now() | date(format="%Y%m%d%H%M%S" )}}
   }
}

Rendering template by tera (Tera is Jinja2 like template engine).

When use custom path you specify a command line arguments.

cargo run -- --templates /path/to/templates

Hooks

Can run python hook scripts before responses.

fakey-cognito calls a hook function in snake_case action name python script.
A hook function takes a request json body string and should return a json string for using a response template.

Example for AdminGetUser action hook script (e.g.hooks/admin_get_user.py).

def hook(request):
    return '{ "json": "response" }'

Default hook scripts directory path is ./hooks.
When use custom path you specify a command line arguments.

cargo run -- --hooks /path/to/hooks

⚠️ Unsupported features

• Request parameter validations
• Error response with corrected messages (but supported error types)
• No check any authentication and authorization

License

Fakey Cognito(fakey-cognito) is under MIT License

Authors

• naokirin