> ## Documentation Index
> Fetch the complete documentation index at: https://ravion-b90c0359-devin-1786804702-tf-policy-checks.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# View and query module logs in CloudWatch

> Stream and query CloudWatch logs for a Ravion module, including filtering, time ranges, and structured log fields from the dashboard.

Modules that emit logs have a **Logs tab** on their page in the dashboard. Logs are **queried live from CloudWatch in your AWS account** — Ravion never ingests or stores your log data.

From the Logs tab you can sort, filter, and select custom time ranges.

## Log sources

Each entry in the Logs tab is a **log source**: a CloudWatch log group the module writes to, declared in the module's [definition](/modules/overview). A module can have several sources — for example, [`rvn-aurora`](/module-definitions/catalog/rvn-aurora) shows one per enabled CloudWatch log export type (`postgresql` for PostgreSQL, or `audit`, `error`, `general`, and `slowquery` for MySQL).

Where standard-library modules send their logs:

| Module                                                                              | Log group                                                                                                                                       |
| ----------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------- |
| ECS services ([`rvn-ecs-web`](/module-definitions/catalog/rvn-ecs-web) and friends) | App container stdout/stderr via the `awslogs` driver to the service's log group.                                                                |
| [`rvn-ec2-service`](/module-definitions/catalog/rvn-ec2-service)                    | `/ravion/ec2/<service-name>`, with a distinct stream per deployment and instance. Deploy-script output is copied into the same instance stream. |
| [`rvn-lambda`](/module-definitions/catalog/rvn-lambda)                              | `/aws/lambda/<function-name>`, created by the module by default.                                                                                |

Log **retention** is controlled by the module where applicable — for example, `rvn-lambda` has a log retention days input.

## Shipping logs elsewhere

The Logs tab doesn't replace a dedicated log platform — it has no full-text indexing or long-term analytics. ECS modules support **FireLens log routing** to send app logs to destinations such as Datadog, Splunk, Firehose, OpenSearch, or S3 through a Fluent Bit sidecar. Keep the CloudWatch output enabled alongside external destinations so the Logs tab and Ravion runtime logs continue to work.

## Querying logs from the CLI

The [`ravion logs cloudwatch`](/cli/reference/logs) command queries any CloudWatch log group through Ravion's credential resolution — the same mechanism the dashboard uses — so scripts and agents don't need their own AWS credentials:

```bash theme={null}
ravion logs cloudwatch \
  --aws-account-id <awsact-id> \
  --region us-east-1 \
  --log-group-name /ravion/ec2/my-service \
  --start-time 2026-08-07T00:00:00Z \
  --filter-pattern "ERROR" \
  --tail
```

`--tail` switches to live tail mode after fetching historical logs.

<Note>
  **Build and pipeline logs are separate.** A build is a pipeline step, not a module log source — use
  [`ravion logs pipeline-step <step-execution-id>`](/cli/reference/logs) to stream those.
</Note>

## For module authors

Declare log sources in the `ui.logs` array of your module definition. Each entry has a stable `id`, a display `name`, and a CloudWatch `source` — AWS account, region, log group, and an optional log stream prefix and filter pattern. Every field is templateable, so sources typically reference stack outputs like the created log group name.

See [UILog](/module-definitions/definition-schema/ui#uilog) in the definition schema.