fix: return an error when docker host cannot be retrieved (#3613)

Author: ash2k

docker_client.go

@@ -73,13 +73,17 @@ func (c *DockerClient) Info(ctx context.Context, options client.InfoOptions) (cl
 		infoLabels += infoLabelsSb72.String()
 	}
 
+	host, err := core.ExtractDockerHost(ctx)
+	if err != nil {
+		return dockerInfo, err
+	}
 	log.Printf(infoMessage, packagePath,
 		dockerInfo.Info.ServerVersion,
 		c.ClientVersion(),
 		dockerInfo.Info.OperatingSystem, dockerInfo.Info.MemTotal/1024/1024,
 		infoLabels,
 		internal.Version,
-		core.MustExtractDockerHost(ctx),
+		host,
 		core.MustExtractDockerSocket(ctx),
 		core.SessionID(),
 		core.ProcessID(),

internal/core/client.go

@@ -12,9 +12,12 @@ import (
 
 // NewClient returns a new docker client extracting the docker host from the different alternatives
 func NewClient(ctx context.Context, ops ...client.Opt) (*client.Client, error) {
-	tcConfig := config.Read()
+	dockerHost, err := ExtractDockerHost(ctx)
+	if err != nil {
+		return nil, err
+	}
 
-	dockerHost := MustExtractDockerHost(ctx)
+	tcConfig := config.Read()
 
 	opts := []client.Opt{client.FromEnv}
 	if dockerHost != "" {

internal/core/docker_host.go

@@ -31,8 +31,9 @@ var (
 )
 
 var (
-	dockerHostCache string
-	dockerHostOnce  sync.Once
+	dockerHostCache    string
+	dockerHostErrCache error
+	dockerHostOnce     sync.Once
 )
 
 var (
@@ -85,16 +86,18 @@ var dockerHostCheck = func(ctx context.Context, host string) error {
 //  6. Rootless docker socket path.
 //  7. Else, because the Docker host is not set, it panics.
 func MustExtractDockerHost(ctx context.Context) string {
-	dockerHostOnce.Do(func() {
-		cache, err := extractDockerHost(ctx)
-		if err != nil {
-			panic(err)
-		}
+	host, err := ExtractDockerHost(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return host
+}
 
-		dockerHostCache = cache
+func ExtractDockerHost(ctx context.Context) (string, error) {
+	dockerHostOnce.Do(func() {
+		dockerHostCache, dockerHostErrCache = extractDockerHost(ctx)
 	})
-
-	return dockerHostCache
+	return dockerHostCache, dockerHostErrCache
 }
 
 // MustExtractDockerSocket Extracts the docker socket from the different alternatives, removing the socket schema and

provider.go

@@ -141,15 +141,18 @@ func NewDockerProvider(provOpts ...DockerProviderOption) (*DockerProvider, error
 	}
 
 	ctx := context.Background()
+	host, err := core.ExtractDockerHost(ctx)
+	if err != nil {
+		return nil, err
+	}
 	c, err := NewDockerClientWithOpts(ctx)
 	if err != nil {
 		return nil, err
 	}
-
 	return &DockerProvider{
 		DockerProviderOptions: o,
-		host:                  core.MustExtractDockerHost(ctx),
 		client:                c,
+		host:                  host,
 		config:                config.Read(),
 	}, nil
 }