fix: retry transient errors on api autocomplete status GET

[vtushar06]

Description

Follow-up to #106 (thanks @ameijer for catching that the retries weren't firing). The connection resets in that run were on the OpenCost API client path, not the Prometheus client I hardened in #106.

API.GET already retries transport errors, but GetAutocompleteStatus (used by the autocomplete probe and validation tests) used a raw http.Get that bypassed that retry, so a connection reset there failed the run with no retry and no log, e.g.:

failed to probe /allocation/autocomplete: error getting .../model/allocation/autocomplete?...:
Get "...": read tcp ...: read: connection reset by peer

This routes that GET through a small httpGetWithRetry helper that retries transient transport errors with the same MAX_RETRIES and backoff as API.GET, and logs each retry so they show up in the run output. As a bonus it now uses the shared client's timeout instead of the bare http.Get.

Related

Follow-up to #106.

Testing

• Added pkg/api/retry_test.go (deterministic, injected RoundTripper): retries transient errors then succeeds, and returns the error after MAX_RETRIES.
• go build ./..., go vet ./pkg/api/, and the pkg/api tests pass locally.

One thing out of scope: the other failure in that run (TestAllocationAutocompletePrometheusGroundTruth, 74.2% coverage) is a data-coverage assertion, not a network issue, so it's not addressed here.

cc @ameijer

[Copilot]

Pull request overview

This PR hardens the OpenCost API client path used by the autocomplete probe/validation by ensuring /allocation/.../autocomplete status GETs go through the same retry-capable HTTP client path as other API calls, and adds deterministic unit coverage for the retry behavior.

Changes:

• Route GetAutocompleteStatus through a new httpGetWithRetry helper instead of http.Get.
• Add httpGetWithRetry to retry GET transport errors with the existing MAX_RETRIES and a configurable backoff (test-shortenable).
• Add deterministic unit tests for retry success and retry exhaustion via an injected RoundTripper.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
pkg/api/api.go	Adds httpGetWithRetry and a configurable retry backoff used by the autocomplete status path.
pkg/api/autocomplete.go	Switches GetAutocompleteStatus from raw http.Get to the retrying helper using sharedHTTPClient.
pkg/api/retry_test.go	Adds deterministic unit tests covering retry success and retry exhaustion for httpGetWithRetry.

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[vtushar06]

@ameijer went through the run-tests failure, none of it is from my change. 2 are pre-existing demo backend issues unrelated to networking (asset type list out of sync, and node UIDs not matching across metric snapshots), the 3rd is a real conn-reset but on the MCP client not the api client I touched here, can do a follow up for that one if useful. build/vet/unit tests are all green on my end, still approved so good to merge whenever