Logging in the Apollo Router

The Apollo Router accepts a command-line argument to set its log level:

Name	Description
`--log`	The log level, indicating the most severe log message type to include. In ascending order of verbosity, can be one of: `off`, `error`, `warn`, `info`, `debug`, or `trace`. The default value is `info`.

The router also accepts an APOLLO_ROUTER_LOG environment variable with the same possible values as the command-line argument. If you provide both, the command-line argument takes precedence.

Output formats

The Apollo Router supports two logging formats:

Basic logging, primarily for local development
JSON-formatted logging, for compatibility with searchable logging tools like Google Cloud Logging

The router uses basic logging whenever an interactive shell session is attached, and it uses JSON-formatted logging otherwise (e.g., in CI and deployed environments). You can also enforce a specific format in configuration.

Basic logging via shell

Basic logging is mostly used during local development:

1
2022-03-18T10:28:11.090054Z  INFO apollo_router::executable: apollo-router@0.1.0-alpha.9
2
2022-03-18T10:28:11.160650Z  INFO apollo_router: Starting Apollo Router
3
2022-03-18T10:28:11.339906Z  INFO apollo_router: Listening on http://127.0.0.1:4000 🚀

JSON-formatted logging

JSON-formatted logging provides compatibility with common searchable logging tools like Google Cloud Logging. The Apollo Router uses the popular Bunyan format:

1
{"timestamp":"2022-03-18T11:46:41.926942Z","level":"INFO","fields":{"message":"apollo-router@0.1.0-alpha.9"},"target":"apollo_router::executable"}
2
{"timestamp":"2022-03-18T11:46:41.985121Z","level":"INFO","fields":{"message":"Starting Apollo Router"},"target":"apollo_router"}
3
{"timestamp":"2022-03-18T11:46:42.171173Z","level":"INFO","fields":{"message":"Listening on http://127.0.0.1:4000 🚀"},"target":"apollo_router"}
4
{"timestamp":"2022-03-18T11:46:43.453993Z","level":"INFO","fields":{"message":"Stopped"},"target":"apollo_router"}

Basic configuration

This is part of an experimental feature, it means any time until it's stabilized (without the prefix experimental_) we might change the configuration shape or adding/removing features. If you want to give feedback or participate in that feature feel free to join this discussion on GitHub.

By default, the router doesn't log certain values that might contain sensitive data, even if a sufficient log level is set:

Request bodies
Response bodies
Headers

You can enable selective logging of these values via the when_header option:

router.yaml

1
telemetry:
2
  experimental_logging:
3
    format: json # By default it's "pretty" if you are in an interactive shell session
4
    display_filename: true # Display filename where the log is coming from. Default: true
5
    display_line_number: false # Display line number in the file where the log is coming from. Default: true
6
    # If one of these headers matches we will log supergraph and subgraphs requests/responses
7
    when_header:
8
      - name: apollo-router-log-request
9
        value: my_client
10
        headers: true # default: false
11
        body: true # default: false
12
      # log request for all requests coming from Iphones
13
      - name: user-agent
14
        match: ^Mozilla/5.0 (iPhone*
15
        headers: true

Advanced configuration

For more granular control over Apollo Router logging, see the Env Logger documentation.

Distributed caching

Subgraph error inclusion