fix(k8s): thread caller ctx into DialContext exec goroutine

[SarthakB11]

Changes

DialContext receives ctx as a parameter and the outer select watches <-ctx.Done() to return early when the caller cancels. The exec goroutine spawned at line 80, however, called c.exec(context.TODO(), ...) rather than passing ctx. On caller cancellation, DialContext returns immediately, but the goroutine keeps running and the exec stream against kube-apiserver stays open for the lifetime of the parent process.

Pass ctx to c.exec. The outer select still races connectFailure against ctx.Done() and conn.closeWithError is idempotent across both paths.

Dial at line 323 is unchanged. That attach goroutine is intentionally long-lived (held open by emptyBlockingReader waiting on the detach signal) and must outlive the Dial call.

/kind bug

fix: k8s dialer exec goroutine now exits on caller cancellation

[knative-prow]

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[knative-prow]

Hi @SarthakB11. Thanks for your PR.

I'm waiting for a knative member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work.

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[matejvasek]

/ok-to-test

[matejvasek]

https://pkg.go.dev/net#Dialer.DialContext

The provided Context must be non-nil. If the context expires before the connection is complete, an error is returned. Once successfully connected, any expiration of the context will not affect the connection.

[matejvasek]

You cannot use that context.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 57.03%. Comparing base (584c11e) to head (adede99).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3772   +/-   ##
=======================================
  Coverage   57.03%   57.03%           
=======================================
  Files         182      182           
  Lines       21376    21376           
=======================================
  Hits        12191    12191           
  Misses       7953     7953           
  Partials     1232     1232           

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e2e typescript	27.35% <0.00%> (ø)
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unit windows-latest	45.14% <0.00%> (ø)

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[matejvasek]

On caller cancellation, DialContext returns immediately, but the goroutine keeps running and the exec stream against kube-apiserver stays open for the lifetime of the parent process.

Not really as we close the connection. You might replace context.TODO() with different context, but definitely not with the ctx parameter of the DialContext() function. You need to create new context for this.