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The control plane answers a read-only subset of the Loki HTTP API over the node-local log store. Add it to a self-hosted Grafana as a Loki data source and use Explore to search and tail app logs. Nothing is copied into another store.

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Add the data source in Grafana

  1. Create an API token with the read ability in the dashboard (Settings, API tokens).
  2. In Grafana, open Connections, Data sources, Add data source, Loki.
  3. Set URL to your control plane address plus /api/v1/loki, for example https://levelrail.example.com/api/v1/loki.
  4. Turn on Basic auth. Use any user name and paste the token as the password. Alternatively add a custom header Authorization with the value Bearer <token>.
  5. Click Save & test, then open Explore and run {app="web"}.
Apps the token cannot read are left out of results and out of the label values.

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Endpoints

Base path: /api/v1/loki. The paths Grafana builds (/api/v1/loki/loki/api/v1/...) are served too, so the data source URL above works unchanged. All of them require the read ability. Times are unix seconds, unix nanoseconds or RFC3339. limit defaults to 100 and is capped at 5000. direction is backward (newest first, the default) or forward. A range may not exceed 30 days (APP_LOKI_MAX_RANGE), and at most APP_LOG_SIGNATURE_MAX_ROWS lines are scanned per app per query.

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Supported LogQL

  • Stream selector with =, !=, =~ and !~ on app, stream and level. At least one app matcher with = or =~ is required. Regexes are fully anchored, as in Loki.
  • Line filters |=, !=, |~ and !~, chained in any order.
  • level is present when a level could be read from the line or its JSON fields.
Anything else is refused with HTTP 400 and a Loki-style error body ({"status":"error","errorType":"bad_data","error":"..."}) instead of a guessed answer: metric queries (rate, count_over_time, sum), parsers and stages (| json, | logfmt, | line_format, unwrap), and other labels. For counts and trends use the log explorer and the metrics API instead.
Last modified on October 16, 2026