Merge pull request #570 from aluzzardi/docker-socket

docker socket forwarding support

client/client.go

@@ -114,7 +114,11 @@ func (c *Client) buildfn(ctx context.Context, st *state.State, env *environment.
 	// Setup solve options
 	opts := bk.SolveOpt{
 		LocalDirs: localdirs,
-		Session:   []session.Attachable{auth, secrets},
+		Session: []session.Attachable{
+			auth,
+			secrets,
+			solver.NewDockerSocketProvider(),
+		},
 	}
 
 	// Call buildkit solver

solver/dockersocketprovider.go

@@ -0,0 +1,62 @@
+package solver
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"time"
+
+	"github.com/moby/buildkit/session"
+	"github.com/moby/buildkit/session/sshforward"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+)
+
+const (
+	DockerSocketID   = "docker.sock"
+	DockerSocketPath = "/var/run/docker.sock"
+)
+
+type DockerSocketProvider struct {
+}
+
+func NewDockerSocketProvider() session.Attachable {
+	return &DockerSocketProvider{}
+}
+
+func (sp *DockerSocketProvider) Register(server *grpc.Server) {
+	sshforward.RegisterSSHServer(server, sp)
+}
+
+func (sp *DockerSocketProvider) CheckAgent(ctx context.Context, req *sshforward.CheckAgentRequest) (*sshforward.CheckAgentResponse, error) {
+	id := sshforward.DefaultID
+	if req.ID != "" {
+		id = req.ID
+	}
+	if id != DockerSocketID {
+		return &sshforward.CheckAgentResponse{}, fmt.Errorf("invalid socket forward key %s", id)
+	}
+	return &sshforward.CheckAgentResponse{}, nil
+}
+
+func (sp *DockerSocketProvider) ForwardAgent(stream sshforward.SSH_ForwardAgentServer) error {
+	id := sshforward.DefaultID
+
+	opts, _ := metadata.FromIncomingContext(stream.Context()) // if no metadata continue with empty object
+
+	if v, ok := opts[sshforward.KeySSHID]; ok && len(v) > 0 && v[0] != "" {
+		id = v[0]
+	}
+
+	if id != DockerSocketID {
+		return fmt.Errorf("invalid socket forward key %s", id)
+	}
+
+	conn, err := net.DialTimeout("unix", DockerSocketPath, time.Second)
+	if err != nil {
+		return fmt.Errorf("failed to connect to %s: %w", DockerSocketPath, err)
+	}
+	defer conn.Close()
+
+	return sshforward.Copy(context.TODO(), conn, stream, nil)
+}

solver/solver.go

@@ -157,7 +157,11 @@ func (s Solver) Export(ctx context.Context, st llb.State, img *dockerfile2llb.Im
 
 	opts := bk.SolveOpt{
 		Exports: []bk.ExportEntry{output},
-		Session: []session.Attachable{s.opts.Auth, s.opts.Secrets},
+		Session: []session.Attachable{
+			s.opts.Auth,
+			s.opts.Secrets,
+			NewDockerSocketProvider(),
+		},
 	}
 
 	ch := make(chan *bk.SolveStatus)

tests/compute.bats

@@ -106,6 +106,11 @@ setup() {
     assert_output "secret=mySecret"
 }
 
+@test "compute: docker socket" {
+    skip "docker socket support disabled"
+    run "$DAGGER" compute  "$TESTDIR"/compute/dockersocket
+}
+
 @test "compute: exclude" {
     "$DAGGER" up -w "$TESTDIR"/compute/exclude
 }

tests/compute/dockersocket/main.cue

@@ -0,0 +1,18 @@
+package main
+
+import (
+	"dagger.io/dagger/op"
+	"dagger.io/docker"
+)
+
+TestDockerSocket: #up: [
+	op.#Load & {
+		from: docker.#Client
+	},
+
+	op.#Exec & {
+		always: true
+		mount: "/var/run/docker.sock": "docker.sock"
+		args: ["docker", "info"]
+	},
+]