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Using REST APIs with OpenWhisk

After your OpenWhisk environment is enabled, you can use OpenWhisk with your web apps or mobile apps with REST API calls.

For more details about the APIs for actions, activations, packages, rules, and triggers, see the OpenWhisk API documentation.

All the capabilities in the system are available through a REST API. There are collection and entity endpoints for actions, triggers, rules, packages, activations, and namespaces.

These are the collection endpoints:

  • https://$APIHOST/api/v1/namespaces
  • https://$APIHOST/api/v1/namespaces/{namespace}/actions
  • https://$APIHOST/api/v1/namespaces/{namespace}/triggers
  • https://$APIHOST/api/v1/namespaces/{namespace}/rules
  • https://$APIHOST/api/v1/namespaces/{namespace}/packages
  • https://$APIHOST/api/v1/namespaces/{namespace}/activations

The $APIHOST is the OpenWhisk API hostname (for example, localhost, 172.17.0.1, and so on). For the {namespace}, the character _ can be used to specify the user's default namespace.

You can perform a GET request on the collection endpoints to fetch a list of entities in the collection.

There are entity endpoints for each type of entity:

  • https://$APIHOST/api/v1/namespaces/{namespace}
  • https://$APIHOST/api/v1/namespaces/{namespace}/actions/[{packageName}/]{actionName}
  • https://$APIHOST/api/v1/namespaces/{namespace}/triggers/{triggerName}
  • https://$APIHOST/api/v1/namespaces/{namespace}/rules/{ruleName}
  • https://$APIHOST/api/v1/namespaces/{namespace}/packages/{packageName}
  • https://$APIHOST/api/v1/namespaces/{namespace}/activations/{activationName}

The namespace and activation endpoints support only GET requests. The actions, triggers, rules, and packages endpoints support GET, PUT, and DELETE requests. The endpoints of actions, triggers, and rules also support POST requests, which are used to invoke actions and triggers and enable or disable rules.

All APIs are protected with HTTP Basic authentication. You can use the wskadmin tool to generate a new namespace and authentication. The Basic authentication credentials are in the AUTH property in your ~/.wskprops file, delimited by a colon. You can also retrieve these credentials using the CLI running wsk property get --auth.

The following is an example that uses the cURL command tool to get the list of all packages in the whisk.system namespace:

curl -u USERNAME:PASSWORD https://$APIHOST/api/v1/namespaces/whisk.system/packages
[
  {
    "name": "slack",
    "binding": false,
    "publish": true,
    "annotations": [
      {
        "key": "description",
        "value": "Package that contains actions to interact with the Slack messaging service"
      }
    ],
    "version": "0.0.1",
    "namespace": "whisk.system"
  }
]

In this example the authentication was passed using the -u flag, you can pass this value also as part of the URL as https://USERNAME:PASSWORD@$APIHOST.

The OpenWhisk API supports request-response calls from web clients. OpenWhisk responds to OPTIONS requests with Cross-Origin Resource Sharing headers. Currently, all origins are allowed (that is, Access-Control-Allow-Origin is "*"), the standard set of methods are allowed (that is, Access-Control-Allow-Methods is "GET, DELETE, POST, PUT, HEAD"), and Access-Control-Allow-Headers yields "Authorization, Origin, X-Requested-With, Content-Type, Accept, User-Agent".

Attention: Because OpenWhisk currently supports only one key per namespace, it is not recommended to use CORS beyond simple experiments. Use Web Actions or API Gateway to expose your actions to the public and not use the OpenWhisk authorization key for client applications that require CORS.

Using the CLI verbose mode

The OpenWhisk CLI is an interface to the OpenWhisk REST API. You can run the CLI in verbose mode with the flag -v, this will print truncated information about the HTTP request and response. To print all information use the flag -d for debug.

Note: HTTP request and response bodies will only be truncated if they exceed 1000 bytes.

Let's try getting the namespace value for the current user.

wsk namespace list -v
REQUEST:
[GET]  https://$APIHOST/api/v1/namespaces
Req Headers
{
  "Authorization": [
    "Basic XXXYYYY"
  ],
  "User-Agent": [
    "OpenWhisk-CLI/1.0 (2017-08-10T20:09:30+00:00)"
  ]
}
RESPONSE:Got response with code 200
Resp Headers
{
  "Content-Type": [
    "application/json; charset=UTF-8"
  ]
}
Response body size is 28 bytes
Response body received:
["john@example.com_dev"]

As you can see you the printed information provides the properties of the HTTP request, it performs a HTTP method GET on the URL https://$APIHOST/api/v1/namespaces using a User-Agent header OpenWhisk-CLI/1.0 (<CLI-Build-version>) and Basic Authorization header Basic XXXYYYY. Notice that the authorization value is your base64-encoded OpenWhisk authorization string. The response is of content type application/json.

Actions

Note: In the examples that follow, $AUTH and $APIHOST represent environment variables set respectively to your OpenWhisk authorization key and API host.

To create or update an action send a HTTP request with method PUT on the the actions collection. For example, to create a nodejs:6 action with the name hello using a single file content use the following:

curl -u $AUTH -d '{"namespace":"_","name":"hello","exec":{"kind":"nodejs:6","code":"function main(params) { return {payload:\"Hello \"+params.name}}"}}' -X PUT -H "Content-Type: application/json" https://$APIHOST/api/v1/namespaces/_/actions/hello?overwrite=true

To perform a blocking invocation on an action, send a HTTP request with a method POST and body containing the input parameter name use the following:

curl -u $AUTH https://$APIHOST/api/v1/namespaces/_/actions/hello?blocking=true \
-X POST -H "Content-Type: application/json" \
-d '{"name":"John"}'

You get the following response:

{
  "duration": 2,
  "name": "hello",
  "subject": "john@example.com_dev",
  "activationId": "c7bb1339cb4f40e3a6ccead6c99f804e",
  "publish": false,
  "annotations": [{
    "key": "limits",
    "value": {
      "timeout": 60000,
      "memory": 256,
      "logs": 10
    }
  }, {
    "key": "path",
    "value": "john@example.com_dev/hello"
  }],
  "version": "0.0.1",
  "response": {
    "result": {
      "payload": "Hello John"
    },
    "success": true,
    "status": "success"
  },
  "end": 1493327653769,
  "logs": [],
  "start": 1493327653767,
  "namespace": "john@example.com_dev"
}

If you just want to get the response.result, run the command again with the query parameter result=true

curl -u $AUTH "https://$APIHOST/api/v1/namespaces/_/actions/hello?blocking=true&result=true" \
-X POST -H "Content-Type: application/json" \
-d '{"name":"John"}'

You get the following response:

{
  "payload": "hello John"
}

Annotations and Web Actions

To create an action as a web action, you need to add an annotation of web-export=true for web actions. Since web-actions are publicly accessible, you should protect pre-defined parameters (i.e., treat them as final) using the annotation final=true. If you create or update an action using the CLI flag --web true this command will add both annotations web-export=true and final=true.

Run the curl command providing the complete list of annotations to set on the action

curl -u $AUTH https://$APIHOST/api/v1/namespaces/_/actions/hello?overwrite=true \
-X PUT -H "Content-Type: application/json" \
-d '{"namespace":"_","name":"hello","exec":{"kind":"nodejs:6","code":"function main(params) { return {payload:\"Hello \"+params.name}}"},"annotations":[{"key":"web-export","value":true},{"key":"raw-http","value":false},{"key":"final","value":true}]}'

You can now invoke this action as a public URL with no OpenWhisk authorization. Try invoking using the web action public URL including an optional extension such as .json or .http for example at the end of the URL.

curl https://$APIHOST/api/v1/web/john@example.com_dev/default/hello.json?name=John
{
  "payload": "Hello John"
}

Note that this example source code will not work with .http, see web actions documentation on how to modify.

Sequences

To create an action sequence, you need to create it by providing the names of the actions that compose the sequence in the desired order, so the output from the first action is passed as input to the next action.

$ wsk action create sequenceAction --sequence /whisk.system/utils/split,/whisk.system/utils/sort

Create a sequence with the actions /whisk.system/utils/split and /whisk.system/utils/sort.

curl -u $AUTH https://$APIHOST/api/v1/namespaces/_/actions/sequenceAction?overwrite=true \
-X PUT -H "Content-Type: application/json" \
-d '{"namespace":"_","name":"sequenceAction","exec":{"kind":"sequence","components":["/whisk.system/utils/split","/whisk.system/utils/sort"]},"annotations":[{"key":"web-export","value":true},{"key":"raw-http","value":false},{"key":"final","value":true}]}'

Take into account when specifying the names of the actions, they have to be full qualified.

Triggers

To create a trigger, the minimum information you need is a name for the trigger. You could also include default parameters that get passed to the action through a rule when the trigger gets fired.

Create a trigger with name events with a default parameter type with value webhook set.

curl -u $AUTH https://$APIHOST/api/v1/namespaces/_/triggers/events?overwrite=true \
-X PUT -H "Content-Type: application/json" \
-d '{"name":"events","parameters":[{"key":"type","value":"webhook"}]}'

Now whenever you have an event that needs to fire this trigger it just takes an HTTP request with a method POST using the OpenWhisk Authorization key.

To fire the trigger events with a parameter temperature, send the following HTTP request.

curl -u $AUTH https://$APIHOST/api/v1/namespaces/_/triggers/events \
-X POST -H "Content-Type: application/json" \
-d '{"temperature":60}'

Triggers with Feed Actions

There are special triggers that can be created using a feed action. The feed action it's an action that helps with the configuration of a feed provider that will be in charge of firing the trigger whenever there is an event for the trigger. Learn more about these feed providers in the [feeds.md] documentation.

Some of the available triggers that leverage a feed action are periodic/alarms, Slack, Github, Cloudant/Couchdb, and messageHub/Kafka. You also can create your own feed action and feed provider.

Let's create a trigger with name periodic to be fired at a specified frequency, every 2 hours (i.e. 02:00:00, 04:00:00, ...).

Using the CLI this will be done with one command

wsk trigger create periodic --feed /whisk.system/alarms/alarm \
  --param cron "0 */2 * * *" -v

As you will see because we are using the -v flag is that two HTTP requests are sent, one is to create a trigger periodic and the other is to invoke a feed action /whisk.system/alarms/alarm with the parameters to configure the feed provider to fire the trigger every 2 hours.

To do the same with the REST API, lets create the trigger first

curl -u $AUTH https://$APIHOST/api/v1/namespaces/_/triggers/periodic?overwrite=true \
-X PUT -H "Content-Type: application/json" \
-d '{"name":"periodic","annotations":[{"key":"feed","value":"/whisk.system/alarms/alarm"}]}'

As you can see the annotation feed is stored in the trigger. Later we will use this annotation to know which feed action to use when deleting the trigger.

Now that the trigger is created, lets invoke the feed action

curl -u $AUTH "https://$APIHOST/api/v1/namespaces/whisk.system/actions/alarms/alarm?blocking=true&result=false" \
-X POST -H "Content-Type: application/json" \
-d "{\"authKey\":\"$AUTH\",\"cron\":\"0 */2 * * *\",\"lifecycleEvent\":\"CREATE\",\"triggerName\":\"/_/periodic\"}"

Deleting the trigger is a similar to creating the trigger, this time deleting the trigger and also using the feed action to configure the feed provider to delete the handler for the trigger.

Invoke the feed action to delete the trigger handler from the feed provider

curl -u $AUTH "https://$APIHOST/api/v1/namespaces/whisk.system/actions/alarms/alarm?blocking=true&result=false" \
-X POST -H "Content-Type: application/json" \
-d "{\"authKey\":\"$AUTH\",\"lifecycleEvent\":\"DELETE\",\"triggerName\":\"/_/periodic\"}"

Now delete the trigger with a HTTP request using DELETE method

curl -u $AUTH https://$APIHOST/api/v1/namespaces/_/triggers/periodic \
-X DELETE -H "Content-Type: application/json"

Rules

To create a rule that associates a trigger with an action, send a HTTP request with a PUT method providing the trigger and action in the body of the request.

curl -u $AUTH https://$APIHOST/api/v1/namespaces/_/rules/t2a?overwrite=true \
-X PUT -H "Content-Type: application/json" \
-d '{"name":"t2a","status":"","trigger":"/_/events","action":"/_/hello"}'

Rules can be enabled or disabled, and you can change the status of the rule by updating its status property. For example, to disable the rule t2a send in the body of the request status: "inactive" with a POST method.

curl -u $AUTH https://$APIHOST/api/v1/namespaces/_/rules/t2a?overwrite=true \
-X POST -H "Content-Type: application/json" \
-d '{"status":"inactive","trigger":null,"action":null}'

Packages

To create an action in a package you have to create a package first, to create a package with name iot send an HTTP request with a PUT method

curl -u $AUTH https://$APIHOST/api/v1/namespaces/_/packages/iot?overwrite=true \
-X PUT -H "Content-Type: application/json" \
-d '{"namespace":"_","name":"iot"}'

Activations

To get the list of the last 3 activations use a HTTP request with a GET method, passing the query parameter limit=3

curl -u $AUTH https://$APIHOST/api/v1/namespaces/_/activations?limit=3

To get all the details of an activation including results and logs, send a HTTP request with a GET method passing the activation identifier as a path parameter

curl -u $AUTH https://$APIHOST/api/v1/namespaces/_/activations/f81dfddd7156401a8a6497f2724fec7b
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