Sample application demonstrating Google Cloud Deployment Manager custom API server.

Custom Type Providers allows you to define your own API server for provisioning tasks outside of GCP resources.

That is, you can run your own API server to perform CRUD operations along with any other GCP resource management changes and even chain dependencies and outputs of your API server into GCP or other resources.

Deployment Manager 'knows' about your API server by consuming a swagger 2.0 specification file that you need to provide to it during setup.

• DM Type Provider

In this example, a very simple REST API "TODO Server" runs on AppEngine (python + Flask-RestPlus) that accepts key-values as tasks in response to DM actions.

The REST API server is protected by a static, hardcoded API key which is also transmitted by DM during its operations.

Finally, the output of of the 'add-task' operation is shown in the output so you can take actions based on that or apply them elsewhere.

The sample API server is the basic "Flask-RestPlus" API server which automatically creates a swagger file DM can consume

So, the first step is to deploy the application to GAE (assuming you set a Google Cloud Account and installed the gcloud SDK:

cd gae

pip install -t lib -r requirements.txt

gcloud app deploy app.yaml --version dmapi --no-promote

The step above will deploy the "TODO" server to version 'dm-api' and will not promote the app to default.

Test the APP is available (ofcourse substitute YOUR-PROJECT everywhere below for your real one) by going to

• https://dmapi-dot-YOUR_PROJECT.appspot.com/#/todos
• https://dmapi-dot-YOUR_PROJECT.appspot.com/swagger.json

via curl:

• List Tasks:

$  curl  -X GET "https://dmapi-dot-YOUR_PROJECT.appspot.com/todos" -H 'X-API-KEY: foo'
{
    "items": []
}

(should show nothing, (as expected))

Now that the API server is deployed, edit

custom_type_provider.yaml and set the swagger_url parameter to your GAE endpoint's swagger file.

Then run the deployment

gcloud deployment-manager deployments create todorest --config custom_type_provider.yaml

Once it completes, you should see

NAME                 TYPE                                                 STATE      ERRORS  INTENT
add-task             YOUR_PROJECT/tasks-type-provider:/todos/{id}         COMPLETED  []
delete-task          YOUR_PROJECT/tasks-type-provider:/todos/{id}         COMPLETED  []
tasks-type-provider  deploymentmanager.v2beta.typeProvider                COMPLETED  []

$  curl  -X GET "https://dmapi-dot-YOUR_PROJECT.appspot.com/todos" -H 'X-API-KEY: foo'
{
    "items": [
        {
            "id": 1135, 
            "task": "some task"
        }
    ]
}

gcloud deployment-manager deployments delete todorest

(if your API server is down during the operation for whatever reason try using the --delete-policy=ABANDON flag)

$  curl  -X GET "https://dmapi-dot-YOUR_PROJECT.appspot.com/todos" -H 'X-API-KEY: foo'
{
    "items": []
}

You can capture the output of your own API (the parts it returns in the API call, by referencing them directly in the tempalte or as Outputs)

• https://cloud.google.com/deployment-manager/docs/configuration/expose-information-outputs#looking_up_final_output_values

eg, the output may look like:

Its recommended to follow the Google API Design Guide when setting up the API server

In the example here, the (Create, List) operations occur at the collection /todo while the (DELETE,GET,PUT) happens on the resource: /todo/{id}.

/todo
  post:
  get:
/todo/{id}
  get:
  delete:
  put:

When defining the DM template use the GET resource as the TYPE-Provider:

{% set RC_TYPE_PROVIDER = env['project'] + '/tasks-type-provider:/todos/{id}' %}

The library used has a very nice UI for testing too which you can access at the root path of your API server

You may also want to use Cloud Endpoints if running elsewhere or developing a new API!: