Forge Container services is now in Preview, and therefore fully supported. However, it remains under active development and may be subject to shorter deprecation windows. Preview features are suitable for early adopters in production environments.

We release preview features so partners and developers can study, test, and integrate them prior to General Availability (GA). For more details, see Forge EAP, Preview, and GA.

For compatibility with Forge’s developer tools we apply default properties to log lines produced by your app. You can specify values by including the following properties in JSON-formatted log lines (written to standard output).

Arbitrary additional key-value pairs are allowed

Any extra JSON properties you include are preserved and appear in the Developer Console alongside the supported properties below.

Property	Description	Type	Default
`ts`	Time that the log was ingested by the Forge platform.	`number`	Unix epoch timestamp, in milliseconds
`level`	Importance of log.	`string` values: `INFO` `TRACE` `DEBUG` `WARN` `ERROR` `FATAL`	`INFO`
`msg`	Arbitrary log message.	`string`	Entire log line
`forge_invocation`	Per-request invocation specific metadata such as invocation id, and installation context (encoded in `base64`). From the `x-forge-invocation-log-attributes` header that is provided on requests to your container.	`string`	None. When possible, add this property to your logs.

Invocation metadata

We strongly advise that you include app invocation metadata to each log, whenever possible. Forge uses invocation IDs to associate logs with the corresponding customer, installation, and request. In addition, customers can only download and share app logs that contain invocation IDs.

For example, consider the following log:

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{
    "ts": 1754624452000,
    "level": "WARN",
    "msg": "Something unexpected happened",
    "forge_invocation": "eyJpZCI6IjVmNmM3YjQ2LTY5NjctNGQ4OC05M2YxLWE1NDUyY2U4ZmFiMSIsImN0eCI6ImFyaTpjbG91ZDpqaXJhOmZjOTZjZmYzLTcwMjctNDBiMi1iMDI4LTg3ZjZkZmFmM2UwOTp3b3Jrc3BhY2UvYTg5ODE3ODMtNjk0MS00NmU4LWI2NjgtYzY4ZWZlNTM4NTI2IiwidHJhY2VJZCI6Ijg1M2VjM2JjNGQ0YjQ1MTY4YjNkNjcyMTUxNmFmM2U0In0="
}

This line would populate the Developer Console with the following entry:

Developer Consoler sample entry for log line