Uses external task client to redirect variable microservices to modules
Acts as an interface between Camunda and other microservices and executes simple tasks. Implemented using the External Task Client from Camunda (https://github.com/camunda/camunda-external-task-client-js).
Default method for setting configurations options is the .env file.
If you are using PM2 as process manager, you can use their ecosystem json file declaration (sample in app.json.sample). In case of PM2 delete the .env file, because it will overwrite the variables of PM2.
| Variable | Type | Optional | Default | Values | Description |
|---|---|---|---|---|---|
| NODE_ENV | String | - | development; staging; production | node environment | |
| TOPIC | String | - | external service task topic | ||
| ASYNC_RESPONSE_TIMEOUT | Number | X | - | External Task Client Docs | |
| MAX_TASK | Number | X | 10 | External Task Client Docs | |
| INTERVAL | Number | X | 300 | External Task Client Docs | |
| LOCK_DURATION | Number | X | 50000 | External Task Client Docs | |
| BASE_URL | String | X | http://localhost:8080/engine-rest | External Task Client Docs | |
| WORKER_ID | String | X | default-worker | External Task Client Docs | |
| AUTH | Boolean | X | false | Use basic auth for REST | |
| USER | String | X | - | Basic auth user | |
| PASS | String | X | - | Basic auth password |
Place a service task in your BPMN and configure it to use the external microservice (see the sample BPMN).
This service will grab the task and execute the specified module.
The module is specified as input parameter named "micro-api-module" and as value the filename of the
the module (without extension).
You can set more input variables in the service task to use them directly in the module. Modules then take care of some service (e.g. Query another API, build a PDF, download stuff etc.).
Sample folder holds a BPMN using the "just-complete"-Microservice. It just completes the service successfully.
The http-request calls a mock server for some JSON and sets a process variable.
The concept differs in the way the Camunda external task client works by using the variable module name instead of using a variable topic name.
Bernd Rücker talks about this kind of concept and wether it's a good or bad practice.
A discussion about it can be found in the Camunda forum:
https://forum.camunda.org/t/microservices-external-tasks-not-the-best-practice/15387
MIT License
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