ROUTER-130-error-handling-router-errors-poc

[BrynCooke]

This is POC that show show we can use macros to enforce structure on error types within the router and also allow custom error formatting.

Each error is required to have an external definitions file that contains information that is not encodable in a thiserror enum.

For instance: apollo_router::structured_errors::test::TestError.yaml

- code: TEST_ERROR__BAD_REQUEST
  level: error
  origin: subgraph
  detail: "The request was invalid or cannot be otherwise served."
  type: bad_request
  actions:
    - "Do something"
  attributes:
    name:
        type: string
        description: "The name of the entity."

- code: TEST_ERROR__NOT_FOUND
  level: error
  origin: subgraph
  type: failed_precondition
  detail: "The requested resource could not be found but may be available in the future."
  actions:
    - "Do something"
  attributes:
    attr:
      type: string
      description: "Some attribute"

A new trait StructuredError is introduced that allows access to this data directly from the error.

In addition a new trait ErrorFormatter is introduced to allow plugins to format errors correctly when attaching errors to a graphql response.

---

Checklist

Complete the checklist (and note appropriate exceptions) before the PR is marked ready-for-review.

• [ ] Changes are compatible[^1]
• [ ] Documentation[^2] completed
• [ ] Performance impact assessed and acceptable
• Tests added and passing[^3]
  • [ ] Unit Tests
  • [ ] Integration Tests
  • [ ] Manual Tests

Exceptions

Note any exceptions here

Notes

[^1]: It may be appropriate to bring upcoming changes to the attention of other (impacted) groups. Please endeavour to do this before seeking PR approval. The mechanism for doing this will vary considerably, so use your judgement as to how and when to do this. [^2]: Configuration is an important part of many changes. Where applicable please try to document configuration examples. [^3]: Tick whichever testing boxes are applicable. If you are adding Manual Tests, please document the manual testing (extensively) in the Exceptions.

[github-actions[bot]]

@BrynCooke, please consider creating a changeset entry in /.changesets/. These instructions describe the process and tooling.

[router-perf[bot]]

CI performance tests

• [ ] reload - Reload test over a long period of time at a constant rate of users
• [ ] events_big_cap_high_rate_callback - Stress test for events with a lot of users, deduplication enabled and high rate event with a big queue capacity using callback mode
• [ ] events_without_dedup_callback - Stress test for events with a lot of users and deduplication DISABLED using callback mode
• [ ] large-request - Stress test with a 1 MB request payload
• [x] const - Basic stress test that runs with a constant number of users
• [ ] no-graphos - Basic stress test, no GraphOS.
• [ ] step-jemalloc-tuning - Clone of the basic stress test for jemalloc tuning
• [ ] events - Stress test for events with a lot of users and deduplication ENABLED
• [ ] events_callback - Stress test for events with a lot of users and deduplication ENABLED in callback mode
• [ ] events_big_cap_high_rate - Stress test for events with a lot of users, deduplication enabled and high rate event with a big queue capacity
• [ ] events_without_dedup - Stress test for events with a lot of users and deduplication DISABLED
• [ ] xxlarge-request - Stress test with 100 MB request payload
• [ ] xlarge-request - Stress test with 10 MB request payload
• [x] step - Basic stress test that steps up the number of users over time