build: set local sharedkey per project basename

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

build/build.go

@@ -3,6 +3,8 @@ package build
 import (
 	"bufio"
 	"context"
+	"crypto/rand"
+	"encoding/hex"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -334,7 +336,7 @@ func toRepoOnly(in string) (string, error) {
 	return strings.Join(out, ","), nil
 }
 
-func toSolveOpt(ctx context.Context, d driver.Driver, multiDriver bool, opt Options, bopts gateway.BuildOpts, pw progress.Writer, dl dockerLoadCallback) (solveOpt *client.SolveOpt, release func(), err error) {
+func toSolveOpt(ctx context.Context, d driver.Driver, multiDriver bool, opt Options, bopts gateway.BuildOpts, configDir string, pw progress.Writer, dl dockerLoadCallback) (solveOpt *client.SolveOpt, release func(), err error) {
 	defers := make([]func(), 0, 2)
 	releaseF := func() {
 		for _, f := range defers {
@@ -511,6 +513,13 @@ func toSolveOpt(ctx context.Context, d driver.Driver, multiDriver bool, opt Opti
 	}
 	defers = append(defers, releaseLoad)
 
+	if sharedKey := so.LocalDirs["context"]; sharedKey != "" {
+		if p, err := filepath.Abs(sharedKey); err == nil {
+			sharedKey = filepath.Base(p)
+		}
+		so.SharedKey = sharedKey + ":" + tryNodeIdentifier(configDir)
+	}
+
 	if opt.Pull {
 		so.FrontendAttrs["image-resolve-mode"] = "pull"
 	}
@@ -574,7 +583,7 @@ func toSolveOpt(ctx context.Context, d driver.Driver, multiDriver bool, opt Opti
 	return &so, releaseF, nil
 }
 
-func Build(ctx context.Context, drivers []DriverInfo, opt map[string]Options, docker DockerAPI, auth Auth, w progress.Writer) (resp map[string]*client.SolveResponse, err error) {
+func Build(ctx context.Context, drivers []DriverInfo, opt map[string]Options, docker DockerAPI, auth Auth, configDir string, w progress.Writer) (resp map[string]*client.SolveResponse, err error) {
 	if len(drivers) == 0 {
 		return nil, errors.Errorf("driver required for build")
 	}
@@ -626,7 +635,7 @@ func Build(ctx context.Context, drivers []DriverInfo, opt map[string]Options, do
 				hasMobyDriver = true
 			}
 			opt.Platforms = dp.platforms
-			so, release, err := toSolveOpt(ctx, d, multiDriver, opt, dp.bopts, w, func(name string) (io.WriteCloser, func(), error) {
+			so, release, err := toSolveOpt(ctx, d, multiDriver, opt, dp.bopts, configDir, w, func(name string) (io.WriteCloser, func(), error) {
 				return newDockerLoader(ctx, docker, name, w)
 			})
 			if err != nil {
@@ -1175,3 +1184,28 @@ func wrapWriteCloser(wc io.WriteCloser) func(map[string]string) (io.WriteCloser,
 		return wc, nil
 	}
 }
+
+var nodeIdentifierMu sync.Mutex
+
+func tryNodeIdentifier(configDir string) (out string) {
+	nodeIdentifierMu.Lock()
+	defer nodeIdentifierMu.Unlock()
+	sessionFile := filepath.Join(configDir, ".buildNodeID")
+	if _, err := os.Lstat(sessionFile); err != nil {
+		if os.IsNotExist(err) { // create a new file with stored randomness
+			b := make([]byte, 8)
+			if _, err := rand.Read(b); err != nil {
+				return out
+			}
+			if err := ioutil.WriteFile(sessionFile, []byte(hex.EncodeToString(b)), 0600); err != nil {
+				return out
+			}
+		}
+	}
+
+	dt, err := ioutil.ReadFile(sessionFile)
+	if err == nil {
+		return string(dt)
+	}
+	return
+}

commands/bake.go

@@ -9,6 +9,7 @@ import (
 	"github.com/containerd/containerd/platforms"
 	"github.com/docker/buildx/bake"
 	"github.com/docker/buildx/build"
+	"github.com/docker/buildx/util/confutil"
 	"github.com/docker/buildx/util/progress"
 	"github.com/docker/buildx/util/tracing"
 	"github.com/docker/cli/cli/command"
@@ -155,7 +156,7 @@ func runBake(dockerCli command.Cli, targets []string, in bakeOptions) (err error
 		return nil
 	}
 
-	resp, err := build.Build(ctx, dis, bo, dockerAPI(dockerCli), dockerCli.ConfigFile(), printer)
+	resp, err := build.Build(ctx, dis, bo, dockerAPI(dockerCli), dockerCli.ConfigFile(), confutil.ConfigDir(dockerCli), printer)
 	if err != nil {
 		return err
 	}

commands/build.go

@@ -10,6 +10,7 @@ import (
 
 	"github.com/docker/buildx/build"
 	"github.com/docker/buildx/util/buildflags"
+	"github.com/docker/buildx/util/confutil"
 	"github.com/docker/buildx/util/platformutil"
 	"github.com/docker/buildx/util/progress"
 	"github.com/docker/buildx/util/tracing"
@@ -224,7 +225,7 @@ func buildTargets(ctx context.Context, dockerCli command.Cli, opts map[string]bu
 
 	printer := progress.NewPrinter(ctx2, os.Stderr, progressMode)
 
-	resp, err := build.Build(ctx, dis, opts, dockerAPI(dockerCli), dockerCli.ConfigFile(), printer)
+	resp, err := build.Build(ctx, dis, opts, dockerAPI(dockerCli), dockerCli.ConfigFile(), confutil.ConfigDir(dockerCli), printer)
 	err1 := printer.Wait()
 	if err == nil {
 		err = err1

commands/util.go

@@ -4,12 +4,12 @@ import (
 	"context"
 	"net/url"
 	"os"
-	"path/filepath"
 	"strings"
 
 	"github.com/docker/buildx/build"
 	"github.com/docker/buildx/driver"
 	"github.com/docker/buildx/store"
+	"github.com/docker/buildx/util/confutil"
 	"github.com/docker/buildx/util/platformutil"
 	"github.com/docker/buildx/util/progress"
 	"github.com/docker/cli/cli/command"
@@ -27,27 +27,13 @@ import (
 
 // getStore returns current builder instance store
 func getStore(dockerCli command.Cli) (*store.Txn, func(), error) {
-	s, err := store.New(getConfigStorePath(dockerCli))
+	s, err := store.New(confutil.ConfigDir(dockerCli))
 	if err != nil {
 		return nil, nil, err
 	}
 	return s.Txn()
 }
 
-// getConfigStorePath will look for correct configuration store path;
-// if `$BUILDX_CONFIG` is set - use it, otherwise use parent directory
-// of Docker config file (i.e. `${DOCKER_CONFIG}/buildx`)
-func getConfigStorePath(dockerCli command.Cli) string {
-	if buildxConfig := os.Getenv("BUILDX_CONFIG"); buildxConfig != "" {
-		logrus.Debugf("using config store %q based in \"$BUILDX_CONFIG\" environment variable", buildxConfig)
-		return buildxConfig
-	}
-
-	buildxConfig := filepath.Join(filepath.Dir(dockerCli.ConfigFile().Filename), "buildx")
-	logrus.Debugf("using default config store %q", buildxConfig)
-	return buildxConfig
-}
-
 // getCurrentEndpoint returns the current default endpoint value
 func getCurrentEndpoint(dockerCli command.Cli) (string, error) {
 	name := dockerCli.CurrentContext()

util/confutil/config.go

@@ -2,11 +2,28 @@ package confutil
 
 import (
 	"os"
+	"path/filepath"
 
+	"github.com/docker/cli/cli/command"
 	"github.com/pelletier/go-toml"
 	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
 )
 
+// ConfigDir will look for correct configuration store path;
+// if `$BUILDX_CONFIG` is set - use it, otherwise use parent directory
+// of Docker config file (i.e. `${DOCKER_CONFIG}/buildx`)
+func ConfigDir(dockerCli command.Cli) string {
+	if buildxConfig := os.Getenv("BUILDX_CONFIG"); buildxConfig != "" {
+		logrus.Debugf("using config store %q based in \"$BUILDX_CONFIG\" environment variable", buildxConfig)
+		return buildxConfig
+	}
+
+	buildxConfig := filepath.Join(filepath.Dir(dockerCli.ConfigFile().Filename), "buildx")
+	logrus.Debugf("using default config store %q", buildxConfig)
+	return buildxConfig
+}
+
 // loadConfigTree loads BuildKit config toml tree
 func loadConfigTree(fp string) (*toml.Tree, error) {
 	f, err := os.Open(fp)