wendu-worker-js

A lightweight Wendu Worker Typescript/Javascript lib for polling the Wendu Orchestration API

Worker Implementation

A worker is a micro-server that performs a task for the Wendu Orchestration engine. A woker should be implemented in the following pattern

1) Register the TaskDefinition with a unique task name this worker performs. Task name should be lowercase with alpha-numerica chars and dashes. For example: copy-file
1) The worker should periodically (interval) poll (GET) the API for tasks in the queue.
1) Once a worker gets a task via polling it should immediately acknowledge (POST) it has received the task. An un-acked task will get requed for other workers.
1) The worker should perform the unique task/work as necessary
1) Once completed (success or failed) the result should be reported (POST) back to the API.

Installation

Install with
``
npm install wendu-worker-js
`

How to Use the Client

$3

Create and reuse this client. It uses under the hood for HTTP calls.

`
const opts: WenduApiOptions = {
url: http://localhost:1331,
pollInterval: 5*1000,
workerIdentity: 'worker-joe',
};

const client = new WenduApiClient(opts);
`

$3

- async register(taskDef: TaskDef): Promise

`
await client.register({
name: 'hello-world',
timeoutPolicy: 'RETRY',
timeoutSeconds: 5,
retryLogic: 'FIXED',
retryCount: 1,
inputKeys: ['name', 'language'],
outputKeys: ['greeting'],
inputTemplate: {}
});
`

$3

- async poll(taskName: string, total: number): Promise

`
const tasks = await client.poll('move-file', 10);
`

$3

- async ack(task: { taskId: string }): Promise

`
const acked = await client.ack(t);
`

$3

- async postResult(result: TaskResult): Promise

`
const result: TaskResult = {
status: 'COMPLETED',
taskId: t.taskId,
output: {
filePath: '//fileshare/temp/newfile.mp3'
},
logs: ['INFO: Moving file']
};

await client.postResult(result);
`

Example Client Code

See example in /test subfolder

$3

1) Create a new directory
2) Use Node 10.8. nvm use 10.8.0
3) Run npm init
4) Run tsc --init (tsc > 3.0.3)

Use the following tsconfig.json options:

`
{ "compilerOptions": {
"target": "es6",
"module": "commonjs",
"moduleResolution": "node",
"typeRoots": [ "node_modules/@types" ]
}
`

5) Run npm install --save-dev @types/node
6) Run npm install --save-dev debug
7) Run npm install --save wendu-worker-test
8) Write a new worker with a new/unique task def
9) Compile and run with tsc && DEBUG=wendu node index.js `