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https://github.com/camunda-community-hub/zeebe-lambda-connector
POC for a worker connecting to AWS Lambda for serverless function orchestration
https://github.com/camunda-community-hub/zeebe-lambda-connector
aws-lambda camunda-8 zeebe
Last synced: 9 days ago
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POC for a worker connecting to AWS Lambda for serverless function orchestration
- Host: GitHub
- URL: https://github.com/camunda-community-hub/zeebe-lambda-connector
- Owner: camunda-community-hub
- License: apache-2.0
- Created: 2020-05-06T09:19:56.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2023-12-15T20:13:57.000Z (11 months ago)
- Last Synced: 2024-08-18T12:03:02.768Z (3 months ago)
- Topics: aws-lambda, camunda-8, zeebe
- Language: Java
- Size: 241 KB
- Stars: 8
- Watchers: 5
- Forks: 3
- Open Issues: 5
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-camunda-platform-8 - Lambda - A Zeebe worker to invoke AWS Lambdas (Serverless functions), allowing to orchestrate functions (Connectors and Bridges)
README
[](https://github.com/camunda-community-hub/community)
[](https://github.com/Camunda-Community-Hub/community/blob/main/extension-lifecycle.md#proof-of-concept-)
# zeebe-lambda-connector
A Zeebe connector to invoke AWS Lambdas (Serverless functions), allowing to orchestrate functions. It uses the AWS SDK to connect to Lambda.
> Requirements: Java 11
**Important Note:** This is a community extension and does not give you any guarantees. In fact, it was developed as part of a POC and might not be ready for production usage yet.
# Usage
## BPMN Service Task
Example service task in BPMN:
Or in the BPMN XML:
```xml
```
* the worker is registered for the type `lambda`
* required headers:
* `functionName` - the function name of the Lambda to invoke
* Optional Headers
* `body` - the payload to send over to the function, can be constructed using placeholders (as explained below)
* `resultName` - the variable the result shall be written to (another variable `resultNameStatusCode` and `resultNameJsonString` is written additionally, see example below)
* `functionErrorCode` - If the function results in an error (status code != 200), you can define a [BPMN Error]() that is raised in this case, which allows to react to failures in your BPMN model (TODO: Think about if the statusCode itself should end up in the BPMN error code, then you could react differently to different errors)
## Placeholders
> Please note that the current way of handling placeholders is subject to change in the future, especially with https://github.com/zeebe-io/zeebe/issues/3417 and the new FEEL expressions.
You can use placeholders in the form of `{{PLACEHOLDER}}` at all places, they will be replaced by
* custom headers from the BPMN model
* Workflow variables
* Configuration Variables from URL (see below)
* `workflowInstanceKey` or `jobKey`
[Mustache](https://github.com/spullara/mustache.java) is used for replacing the placeholders, refer to their docs to check possibilities.
If you want to avoid that the resulting string gets quoted, you have to use triple quotes: `{{{PLACEHOLDER}}}`. This is handy to e.g. pass all variables into the request in the body attribute (which can be the case if your functions are also called via API Gateway):
```
{"body": "{{{variablesJsonEscaped}}}" }
```
Example:
```xml
```
`FUNCTION_BASE` could be configured by the configuration variables from the URL or environment properties.
You can use
* Single Variables by name
* `variablesJson` uses all variable as Json object
* `variablesJsonEscaped` includes all variables as Json String, escaped, to be used as String attribute, e.g. used to call a function that is also called via API Gateway) - use {{{ to prevent the templating to add quotes:
```
{"body": "{{{variablesJsonEscaped}}}" }
```
# Install
## JAR
* Build the JAR file
`mvn clean build`
* Execute the JAR via
`java -jar target/zeebe-lambda-worker-{VERSION}.jar`
## Docker
docker run camunda/zeebe-lambda-worker:SNAPSHOT
Set environment variables as described below to configure the worker. So for example to connect to Camunda Cloud and AWS it could look like this:
```
docker run -e ZEEBE_CLIENT_CLOUD_CLUSTERID=x -e ZEEBE_CLIENT_CLOUD_CLIENTID=y -e ZEEBE_CLIENT_CLOUD_CLIENTSECRET=z -e AWS_ACCESSKEY=a -e AWS_SECRET=b -e AWS_REGION=c -p 8080:8080 camunda/zeebe-lambda-worker:SNAPSHOT
```
Or even easier using environment files:
```
docker run --env-file camunda.env --env-file aws.env -p 8080:8080 camunda/zeebe-lambda-worker:SNAPSHOT
```
with camunda.env:
```
ZEEBE_CLIENT_CLOUD_CLUSTERID=x
ZEEBE_CLIENT_CLOUD_CLIENTID=y
ZEEBE_CLIENT_CLOUD_CLIENTSECRET=z
```
and aws.env:
```
AWS_REGION=eu-central-1
AWS_ACCESSKEY=x
AWS_SECRET=y
```
Of course you can also services like AWS Fargate to run this container.
## Readiness probes
You can check health of the worker:
http://localhost:8080/actuator/health
This uses the Spring Actuator, so other metrics are available as well
# Configuration via Environment Variables
The connection to the broker Zeebe can be changed by setting the environment variables
* `ZEEBE_CLIENT_BROKER_CONTACTPOINT` (default: `127.0.0.1:26500`).
* `ZEEBE_CLIENT_SECURITY_PLAINTEXT` (default: true).
or if you want to connect to Camunda Cloud:
* `ZEEBE_CLIENT_CLOUD_CLUSTERID`
* `ZEEBE_CLIENT_CLOUD_CLIENTID`
* `ZEEBE_CLIENT_CLOUD_CLIENTSECRET`
You also need to specify the AWS credentials to talk to your Lambda:
* `AWS_ACCESSKEY`
* `AWS_SECRET`
* `AWS_REGION`
You could adjust the topic or worker name itself (if you know what you are doing - leave untouched otherwise)
* `ZEEBE_CLIENT_WORKER_DEFAULTNAME` (default `lambda-worker`)
* `ZEEBE_CLIENT_WORKER_DEFAULTTYPE` (default `lambda`)
This worker uses [Spring Zeebe]( https://github.com/zeebe-io/spring-zeebe/) underneath, so all configuration options available there are also available here.
# Configuration Variables from URL
You can load additional configuration values used to substitute placeholders. Therefor the worker will query an HTTP endpoint and expects a JSON back:
```
[
{
"key": "someValue",
"value": 42
},
{
"key": "anotherValue",
"value": 42
}
]
```
To load additional config variables from an URL set these environment variables:
* `ENV_VARS_URL` (e.g. `http://someUrl/config`, default: null)
* `ENV_VARS_RELOAD_RATE` (default `15000`)
* `ENV_VARS_M2M_BASE_URL`
* `ENV_VARS_M2M_CLIENT_ID`
* `ENV_VARS_M2M_CLIENT_SECRET`
* `ENV_VARS_M2M_AUDIENCE`
# Code of Conduct
This project adheres to the Contributor Covenant [Code of
Conduct](/CODE_OF_CONDUCT.md). By participating, you are expected to uphold
this code. Please report unacceptable behavior to [email protected].