Add dotenv to allow router to read environment variables from .env file

[andrewmcgivery]

Add dotenv to allow router to read environment variables from .env file

Possibly worth discussing:

• This is currently implemented to be "on by default". Reason I didn't put this behind a config or option flag is because at that point, it is too late since the options parse environment values. Possible workaround is to do a more "manual" read of the argument separate from the normal parsing code specifically for this flag.

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Checklist

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

• Changes are compatible¹
• Documentation² completed
• Performance impact assessed and acceptable
• Tests added and passing³
  • Unit Tests
  • Integration Tests
  • Manual Tests

Exceptions

Note any exceptions here

Notes

Footnotes

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. ↩

[svc-apollo-docs]

❌ Docs Preview Failed

Error

HttpError: Resource not accessible by personal access token - https://docs.github.com/rest/commits/statuses#create-a-commit-status

[router-perf]

CI performance tests

• connectors-const - Connectors stress test that runs with a constant number of users
• const - Basic stress test that runs with a constant number of users
• demand-control-instrumented - A copy of the step test, but with demand control monitoring and metrics enabled
• demand-control-uninstrumented - A copy of the step test, but with demand control monitoring enabled
• enhanced-signature - Enhanced signature enabled
• events - Stress test for events with a lot of users and deduplication ENABLED
• 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_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_callback - Stress test for events with a lot of users and deduplication ENABLED in callback mode
• events_without_dedup - Stress test for events with a lot of users and deduplication DISABLED
• events_without_dedup_callback - Stress test for events with a lot of users and deduplication DISABLED using callback mode
• extended-reference-mode - Extended reference mode enabled
• large-request - Stress test with a 1 MB request payload
• no-tracing - Basic stress test, no tracing
• reload - Reload test over a long period of time at a constant rate of users
• step-jemalloc-tuning - Clone of the basic stress test for jemalloc tuning
• step-local-metrics - Field stats that are generated from the router rather than FTV1
• step-with-prometheus - A copy of the step test with the Prometheus metrics exporter enabled
• step - Basic stress test that steps up the number of users over time
• xlarge-request - Stress test with 10 MB request payload
• xxlarge-request - Stress test with 100 MB request payload

[goto-bus-stop]

If we do this we should use the dotenvy crate, as dotenv is unmaintained.

[andrewmcgivery]

If we do this we should use the dotenvy crate, as dotenv is unmaintained.

Good catch. Switched to that package!

[bnjjj]

The overall PR LGTM, I would really have this feature in the router because I already struggled with that. I'm just wondering what could be the impact on our existing users ? Could it break something or have weird behavior ? Like for example what if they already had that .env file with wrong values but they're still providing environment variables like they always did before with the right values ? What's the priority order in that case ? Also does it keep the same logics if they use the argument in command line (like --config for example) but they're also providing the APOLLO_ROUTER_CONFIG_PATH ? And what's the behavior now if additionally we provide the same env var in .env file ? I think we need to test it manually (at least) and document it somewhere

[abernix]

Also plenty of folks use direnv or many other tools (including Docker itself) that handles this in their local environment and additionally automatically uses different .env files for different environments.

I'm really not sure that the Router should really take on this concern when there are off the shelf tools that handle this generically. I'd like to know why those other tools can't just be used without introducing this to the Router directly, before we entertain a PR that adds it.