Handle vfkit connection in goroutine to prevent blocking

[vyasgun]

Description

A bug is being consistently seen where crc is unable to connect to the daemon on restart/recreation. This fix will help prevent seeing this issue.

Fixes: #4736

Relates to: #4738

Type of change

• Bug fix (non-breaking change which fixes an issue)
• Feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change
• Chore (non-breaking change which doesn't affect codebase;
  test, version modification, documentation, etc.)

Proposed changes

Testing

Contribution Checklist

• I Keep It Small and Simple: The smaller the PR is, the easier it is to review and have it merged
• I have performed a self-review of my code
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Which platform have you tested the code changes on?
  • Linux
  • Windows
  • MacOS

Summary by Sourcery

Bug Fixes:

• Handle vfkit connections asynchronously to prevent daemon startup from blocking on macOS.

[sourcery-ai]

Reviewer's Guide

Refactors the macOS daemon listener to accept vfkit connections in a background goroutine, eliminating blocking behavior during connection setup and updating error handling to log failures asynchronously.

File-Level Changes

Change	Details	Files
Accept vfkit connection asynchronously to avoid blocking	Moved vn.AcceptVfkit call inside a go routine Replaced wrapped error return with logging.Errorf inside the goroutine Returned initial listener connection and error immediately without waiting	cmd/crc/cmd/daemon_darwin.go

Possibly linked issues

• [bug] crc start fail for darwin on nightly run #4736: PR changes vfkit connection handling in goroutine to fix connection refused error in issue.

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[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

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[sourcery-ai]

Hey @vyasgun - I've reviewed your changes and they look great!

Here's what I looked at during the review

• 🟡 General issues: 1 issue found
• 🟢 Security: all looks good
• 🟢 Testing: all looks good
• 🟢 Documentation: all looks good

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[praveenkumar]

With this change, now it is stuck during fresh start also. Following is logs from daemon, looks like connection is closed.

 - - [15/May/2025:10:51:11 +0530] "GET /network/services/forwarder/all HTTP/1.1" 200 3
 - - [15/May/2025:10:51:11 +0530] "GET /network/services/forwarder/all HTTP/1.1" 200 3
 - - [15/May/2025:10:51:11 +0530] "POST /network/services/forwarder/expose HTTP/1.1" 200 0
 - - [15/May/2025:10:51:11 +0530] "POST /network/services/forwarder/expose HTTP/1.1" 200 0
 - - [15/May/2025:10:51:11 +0530] "POST /network/services/forwarder/expose HTTP/1.1" 200 0
 - - [15/May/2025:10:51:11 +0530] "POST /network/services/forwarder/expose HTTP/1.1" 200 0
 - - [15/May/2025:10:51:11 +0530] "POST /network/services/forwarder/expose HTTP/1.1" 200 0
DEBU new connection from /Users/prkumar/.crc/vfkit-354d-1254.sock to /Users/prkumar/.crc/crc-unixgram.sock 
ERRO cannot receive packets from /Users/prkumar/.crc/vfkit-354d-1254.sock, disconnecting: cannot read size from socket: read unixgram /Users/prkumar/.crc/crc-unixgram.sock: use of closed network connection 
ERRO failed to accept vfkit connection: cannot read size from socket: read unixgram /Users/prkumar/.crc/crc-unixgram.sock: use of closed network connection 
INFO listening on /Users/prkumar/.crc/crc-unixgram.sock 
0B sent to the VM, 0B received from the VM
2025/05/15 10:51:15 tcpproxy: for incoming conn 127.0.0.1:52729, error dialing "192.168.127.2:22": connect tcp 192.168.127.2:22: no route to host
0B sent to the VM, 0B received from the VM

Edit: I had some local changes also during testing and after removing those it is working as expected. will wait for @cfergeau for approval and then merge it.

[cfergeau]

To avoid the cancel/ctx global variables, I’d change unixgramListener to have an additional return value of type CancelFunc. The cancellation can then be handled in the code calling vsockListener.
Even if we keep the code as it is currently, I don’t think ctx needs to be global, only cancel.

And not related to this change, but I wonder if unixgramListen would be a better name for this method instead of unixgramListener (but just a comment in passing, nothing important)

[vyasgun]

I split the function into two: setupUnixgramListener and handleUnixgramConnection since cancel() needs to be called once the initial connection is established (transport.AcceptVfkit returns). The cancellation is now being handled by the caller function.

For the names, what do you think of the two new functions?

[praveenkumar]

CI is failing with following error

GOARCH=arm64 GOOS=darwin go build -tags "containers_image_openpgp" -ldflags="-X github.com/crc-org/crc/v2/pkg/crc/version.crcVersion=2.50.0 -X github.com/crc-org/crc/v2/pkg/crc/version.ocpVersion=4.18.2 -X github.com/crc-org/crc/v2/pkg/crc/version.okdVersion=4.15.0-0.okd-2024-02-23-163410 -X github.com/crc-org/crc/v2/pkg/crc/version.microshiftVersion=4.18.2 -X github.com/crc-org/crc/v2/pkg/crc/version.commitSha=32561c " -o out/macos-arm64/crc  ./cmd/crc
GOARCH=amd64 GOOS=darwin go build -tags "containers_image_openpgp" -ldflags="-X github.com/crc-org/crc/v2/pkg/crc/version.crcVersion=2.50.0 -X github.com/crc-org/crc/v2/pkg/crc/version.ocpVersion=4.18.2 -X github.com/crc-org/crc/v2/pkg/crc/version.okdVersion=4.15.0-0.okd-2024-02-23-163410 -X github.com/crc-org/crc/v2/pkg/crc/version.microshiftVersion=4.18.2 -X github.com/crc-org/crc/v2/pkg/crc/version.commitSha=32561c " -o out/macos-amd64/crc  ./cmd/crc
GOOS=linux GOARCH=amd64 go build -tags "containers_image_openpgp" -ldflags="-X github.com/crc-org/crc/v2/pkg/crc/version.crcVersion=2.50.0 -X github.com/crc-org/crc/v2/pkg/crc/version.ocpVersion=4.18.2 -X github.com/crc-org/crc/v2/pkg/crc/version.okdVersion=4.15.0-0.okd-2024-02-23-163410 -X github.com/crc-org/crc/v2/pkg/crc/version.microshiftVersion=4.18.2 -X github.com/crc-org/crc/v2/pkg/crc/version.commitSha=32561c " -o out/linux-amd64/crc  ./cmd/crc
# github.com/crc-org/crc/v2/cmd/crc/cmd
Error: cmd/crc/cmd/daemon.go:216:17: undefined: setupUnixgramListener
Error: cmd/crc/cmd/daemon.go:221:77: undefined: constants.UnixgramSocketPath
Error: cmd/crc/cmd/daemon.go:226:7: undefined: handleUnixgramConnection

[vyasgun]

@praveenkumar these are due to missing duplicate definitions for other OSes. I will add them

[praveenkumar]

@praveenkumar these are due to missing duplicate definitions for other OSes. I will add them

@vyasgun before push make sure you run make check so that you can locally able to find out issue before hitting by CI.

[vyasgun]

The failing test Test OKD bundle is on Ubuntu 24.04.2 LTS and unrelated to the vfkit changes.

[openshift-ci]

@vyasgun: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
ci/prow/e2e-microshift-crc	4cb88d0	link	true	/test e2e-microshift-crc
ci/prow/integration-crc	4cb88d0	link	true	/test integration-crc
ci/prow/e2e-crc	4cb88d0	link	true	/test e2e-crc

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