juanfont/headscale · error

no docker context found

Error message

no docker context found

What it means

Guard error from doLoginURLWithClient when the caller passes a nil *http.Client. The function needs a real client (with the debug cookie jar) to perform the login GET, so it refuses immediately instead of panicking on hc.Do later.

Source

Thrown at cmd/hi/docker.go:31

	"path/filepath"
	"strings"
	"time"

	"github.com/cenkalti/backoff/v5"
	"github.com/docker/docker/api/types/container"
	"github.com/docker/docker/api/types/image"
	"github.com/docker/docker/api/types/mount"
	"github.com/docker/docker/client"
	"github.com/docker/docker/pkg/stdcopy"
	"github.com/juanfont/headscale/integration/dockertestutil"
)

const defaultDirPerm = 0o755

var (
	ErrTestFailed              = errors.New("test failed")
	ErrUnexpectedContainerWait = errors.New("unexpected end of container wait")
	ErrNoDockerContext         = errors.New("no docker context found")
	ErrMemoryLimitViolations   = errors.New("container(s) exceeded memory limits")
)

// runTestContainer executes integration tests in a Docker container.
//
//nolint:gocyclo // complex test orchestration function
func runTestContainer(ctx context.Context, config *RunConfig) error {
	cli, err := createDockerClient(ctx)
	if err != nil {
		return fmt.Errorf("creating Docker client: %w", err)
	}
	defer cli.Close()

	runID := dockertestutil.GenerateRunID()
	containerName := "headscale-test-suite-" + runID
	logsDir := filepath.Join(config.LogsDir, runID)

	if config.Verbose {

View on GitHub (pinned to 565fd254d0)

Solutions

1. Check the error from newLoginHTTPClient before using the client.
2. Pass the client returned by newLoginHTTPClient(hostname), never a hand-built nil.

Example fix

// before
hc, _ := newLoginHTTPClient(hostname)
body, redir, err := doLoginURLWithClient(hostname, loginURL, hc, true)
// after
hc, err := newLoginHTTPClient(hostname)
if err != nil {
    return nil, nil, err
}
body, redir, err := doLoginURLWithClient(hostname, loginURL, hc, true)

hc, err := newLoginHTTPClient(hostname)
if err != nil {
    return err
}
if hc == nil {
    return fmt.Errorf("%s http client unexpectedly nil", hostname)
}

When it happens

Trigger: Calling doLoginURLWithClient (directly or via a helper) with hc == nil — e.g. the caller ignored the error from newLoginHTTPClient and passed the nil result straight through.

Common situations: Ignoring the error from newLoginHTTPClient and proceeding with the zero-value client; refactoring that dropped client construction from a call path.

Related errors

• system checks failed
• test failed
• unexpected end of container wait
• unknown --set value (want must|all)
• test pattern is required as first argument or use --test fla

AI-assisted analysis of juanfont/headscale@565fd254d0 (2026-08-15). Data as JSON: /api/errors/af0bbd15167f7e6e. Report an issue: GitHub.