In addition to any environment variables pre-configured for your worker via watchbot.template() (see below), Watchbot will provide each worker with a set of environment variables representing the details of the message which it should process:
| Name | Description |
|---|---|
| Subject | the message's subject |
| Message | the message's body |
| MessageId | the message's ID defined by SQS |
| SentTimestamp | the time the message was sent |
| ApproximateFirstReceiveTimestamp | the time the message was first attempted |
| ApproximateReceiveCount | the number of times the message has been attempted |
The environment will also contain some variables referencing resources that Watchbot created:
| Name | Description |
|---|---|
| WorkTopic | the ARN of the SNS topic that provides messages to SQS |
| LogGroup | the name of the CloudWatch LogGroup where logs are sent |
🔒 Encrypting & decrypting environment variables
The recommended flow for deploying Watchbot stacks is to use [cfn-config(http://github.com/mapbox/cfn-config) which provides a --kms option for automatically encrypting CloudFormation parameters marked with [secure]. To decrypt at runtime, install decrypt-kms-env as a dependency in your Dockerfile and invoke it in your CMD. Example:
RUN eval $(./node_modules/.bin/decrypt-kms-env) && npm startThe exit code from your worker determines what the watcher will do with the message that was being processed. Your options are:
| Exit code | Description | Outcome |
|---|---|---|
| 0 | completed successfully | message is removed from the queue without notification |
| 3 | rejected the message | message is removed from the queue and a notification is sent |
| 4 | no-op | message is returned to the queue without notification |
| other | failure | message is returned to the queue and a notification is sent |
When a message is returned to the queue, it will be retried. See the worker retry documentation for more info.