feat: build-on-node — git checkouts, remote image builds, image transport (#60)

Git-sourced deploys never materialized a checkout: sourcePath was
build_path resolved against the server cwd, so builds consumed the
backend's own directory. Remote placement could only run
registry-pulled images.

- internal/source: per-deployment checkout (init/fetch/checkout) at
  branch or commit; GIT_ASKPASS keeps tokens out of argv, .git/config,
  and the build context; dumb-transport and SHA-refusal fallbacks;
  build_path validated inside the checkout.
- BuildManager.PackageContext: produces the same tar context Build
  ships to the daemon — generated Dockerfile at tar root, .git
  excluded. Fixes nixpacks passing the Dockerfile path as content.
- Agent artifact endpoint: GET /api/agents/artifacts/:id streams
  build contexts and docker-save tarballs behind agent-token auth;
  hex-validated ids, per-deployment cleanup, boot-time purge.
- Agent commands: build_image (docker build -, --build-arg values via
  process env, not argv) and load_image (docker load for containr-*
  rollback tags no registry serves).
- Deployment flow: remote git builds package context → artifact →
  node docker-builds the deployment tag; remote rollbacks of local
  tags export via SaveImage → artifact → node docker-loads.

Verified end-to-end: agent-pinned git service built on the node
(build_image → create_container → deployed) and rollback shipped a
docker-save tarball (load_image → deployed). Artifact auth returns
401/404 correctly; workspaces and blobs are removed after deploy.

Authored By: TDvorak <[email protected]>

app/backend/Dockerfile

@@ -30,7 +30,7 @@ COPY auth/src ./src
 # Final runtime image (Go API + Better Auth sidecar in one container)
 FROM node:22-alpine
 
-RUN apk --no-cache add ca-certificates tzdata wget
+RUN apk --no-cache add ca-certificates tzdata wget git
 
 RUN addgroup -g 1001 -S appgroup && \
     adduser -u 1001 -S appuser -G appgroup

app/backend/cmd/agent/main.go

@@ -316,7 +316,7 @@ func processCommands(ctx context.Context, client *http.Client, cfg agentConfig,
 		if item.Type == "self_upgrade" {
 			result, reexecPath, runErr = selfUpgrade(cfg, item.Payload)
 		} else {
-			result, runErr = executeCommand(item)
+			result, runErr = executeCommand(cfg, item)
 		}
 		status := "completed"
 		errText := ""
@@ -343,7 +343,7 @@ func processCommands(ctx context.Context, client *http.Client, cfg agentConfig,
 	return nil
 }
 
-func executeCommand(item command) (string, error) {
+func executeCommand(cfg agentConfig, item command) (string, error) {
 	switch item.Type {
 	case "create_container":
 		return createContainer(item.Payload)
@@ -360,6 +360,10 @@ func executeCommand(item command) (string, error) {
 			return out, nil
 		}
 		return out, err
+	case "build_image":
+		return buildImage(cfg, item.Payload)
+	case "load_image":
+		return loadImage(cfg, item.Payload)
 	case "prune":
 		return dockerPrune(item.Payload)
 	case "system_df":
@@ -568,6 +572,120 @@ func createContainer(payload map[string]interface{}) (string, error) {
 	return string(out), nil
 }
 
+// fetchArtifact downloads a server-side deploy artifact (build context or
+// docker-save tarball) into a temp file the docker CLI consumes.
+func fetchArtifact(cfg agentConfig, artifactID string) (*os.File, error) {
+	if len(artifactID) != 32 {
+		return nil, fmt.Errorf("invalid artifact id")
+	}
+	url := fmt.Sprintf("%s/api/agents/artifacts/%s", cfg.APIURL, artifactID)
+	req, err := http.NewRequest(http.MethodGet, url, nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("X-Containr-Agent-Token", cfg.Token)
+	resp, err := (&http.Client{Timeout: 10 * time.Minute}).Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("download artifact: %w", err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("download artifact: server returned %d", resp.StatusCode)
+	}
+	f, err := os.CreateTemp("", "containr-artifact-*.tar")
+	if err != nil {
+		return nil, err
+	}
+	if _, err := io.Copy(f, resp.Body); err != nil {
+		f.Close()
+		os.Remove(f.Name())
+		return nil, fmt.Errorf("write artifact: %w", err)
+	}
+	if _, err := f.Seek(0, io.SeekStart); err != nil {
+		f.Close()
+		os.Remove(f.Name())
+		return nil, err
+	}
+	return f, nil
+}
+
+// buildImage docker-builds a packaged context tar on this node. The context
+// already carries its Dockerfile at the tar root, so `docker build -` can
+// stream it straight from stdin. Result reports the image digest so the
+// server records what each node actually produced.
+func buildImage(cfg agentConfig, payload map[string]interface{}) (string, error) {
+	image := stringValue(payload["image"])
+	artifactID := stringValue(payload["artifact_id"])
+	if image == "" || artifactID == "" {
+		return "", errors.New("build_image requires image and artifact_id")
+	}
+	f, err := fetchArtifact(cfg, artifactID)
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+	defer os.Remove(f.Name())
+
+	args := []string{"build", "-t", image}
+	if boolValue(payload["no_cache"]) {
+		args = append(args, "--no-cache")
+	}
+	// Bare --build-arg keys read their values from the process env — keeps
+	// token-bearing args out of the node's process list.
+	env := os.Environ()
+	if buildArgs, ok := payload["build_args"].(map[string]interface{}); ok {
+		for k, v := range buildArgs {
+			args = append(args, "--build-arg", k)
+			env = append(env, fmt.Sprintf("%s=%v", k, v))
+		}
+	}
+	args = append(args, "-")
+	cmd := exec.Command("docker", args...)
+	cmd.Stdin = f
+	cmd.Env = env
+	outBytes, err := cmd.CombinedOutput()
+	out := strings.TrimSpace(string(outBytes))
+	if err != nil {
+		return "", fmt.Errorf("docker build failed: %s", tailOutput(out, 4096))
+	}
+	digest, _ := runDocker("inspect", "-f", "{{.Id}}", image)
+	size, _ := runDocker("inspect", "-f", "{{.Size}}", image)
+	result, _ := json.Marshal(map[string]string{
+		"image": image, "id": digest, "size": size,
+		"log_tail": tailOutput(out, 4096),
+	})
+	return string(result), nil
+}
+
+// loadImage imports a docker-save tarball — rollbacks of locally-built tags
+// reach remote nodes this way since no registry serves containr-* images.
+func loadImage(cfg agentConfig, payload map[string]interface{}) (string, error) {
+	artifactID := stringValue(payload["artifact_id"])
+	if artifactID == "" {
+		return "", errors.New("load_image requires artifact_id")
+	}
+	f, err := fetchArtifact(cfg, artifactID)
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+	defer os.Remove(f.Name())
+	out, err := runDockerStdin(f, "load")
+	if err != nil {
+		return "", fmt.Errorf("docker load failed: %s", tailOutput(out, 4096))
+	}
+	return out, nil
+}
+
+// tailOutput bounds command results — full docker build logs would swamp
+// the agent_commands row.
+func tailOutput(s string, max int) string {
+	if len(s) <= max {
+		return s
+	}
+	return s[len(s)-max:]
+}
+
 // registryHostOf mirrors the server's registryHost: first path segment with
 // a "." or ":" is a registry host; bare names mean Docker Hub.
 func registryHostOf(imageRef string) string {
@@ -779,6 +897,15 @@ func runDocker(args ...string) (string, error) {
 	return strings.TrimSpace(string(output)), err
 }
 
+// runDockerStdin pipes stdin into docker — build contexts and saved image
+// tarballs stream in without a second copy on disk.
+func runDockerStdin(stdin io.Reader, args ...string) (string, error) {
+	cmd := exec.Command("docker", args...)
+	cmd.Stdin = stdin
+	output, err := cmd.CombinedOutput()
+	return strings.TrimSpace(string(output)), err
+}
+
 func dockerAvailable() bool {
 	_, err := exec.LookPath("docker")
 	if err != nil {

app/backend/internal/api/agents.go

@@ -769,7 +769,9 @@ func (h *NodeAgentHandler) CompleteCommand(c *gin.Context) {
 }
 
 // scrubCommandSecrets rewrites a completed command's payload with any
-// registry password blanked. Best-effort — a failed scrub leaves the row.
+// credential-bearing fields blanked — registry passwords and build-time
+// args (tokens like NPM_TOKEN ride along as build args). Best-effort — a
+// failed scrub leaves the row.
 func scrubCommandSecrets(ctx context.Context, q *sqlcdb.Queries, commandID string, payload pqtype.NullRawMessage) {
 	if !payload.Valid || len(payload.RawMessage) == 0 {
 		return
@@ -778,15 +780,24 @@ func scrubCommandSecrets(ctx context.Context, q *sqlcdb.Queries, commandID strin
 	if err := json.Unmarshal(payload.RawMessage, &doc); err != nil {
 		return
 	}
-	container, ok := doc["container"].(map[string]interface{})
-	if !ok {
+	dirty := false
+	if container, ok := doc["container"].(map[string]interface{}); ok {
+		if reg, ok := container["registry"].(map[string]interface{}); ok && reg["password"] != nil {
+			reg["password"] = "***"
+			dirty = true
+		}
+	}
+	for _, key := range []string{"build_args", "environment"} {
+		if args, ok := doc[key].(map[string]interface{}); ok && len(args) > 0 {
+			for k := range args {
+				args[k] = "***"
+			}
+			dirty = true
+		}
+	}
+	if !dirty {
 		return
 	}
-	reg, ok := container["registry"].(map[string]interface{})
-	if !ok || reg["password"] == nil {
-		return
-	}
-	reg["password"] = "***"
 	if err := q.ScrubCommandPayload(ctx, sqlcdb.ScrubCommandPayloadParams{
 		ID:      commandID,
 		Payload: rawJSON(doc),
@@ -1458,6 +1469,10 @@ func (h *NodeAgentHandler) SetupPublicRoutes(router *gin.RouterGroup) {
 		// public; the enroll token is the actual secret.
 		agents.GET("/install.sh", h.ServeInstallScript)
 		agents.GET("/download/:platform", h.ServeAgentBinary)
+
+		// Deploy artifacts (build contexts, image tarballs) — token-gated;
+		// the blobs are per-deployment source code, not public bootstrap.
+		agents.GET("/artifacts/:id", h.ServeArtifact)
 	}
 }
 

app/backend/internal/api/artifacts.go

@@ -0,0 +1,136 @@
+package api
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+
+	"github.com/gin-gonic/gin"
+)
+
+// containrWorkDir is the build workspace root — same dir the BuildManager
+// was constructed with; checkouts and agent artifacts live beneath it.
+const containrWorkDir = "/tmp/containr-builds"
+
+// artifacts is a one-shot blob store for node agents: build contexts and
+// docker-save tarballs the server produced on behalf of a deployment. Files
+// live under workdir/artifacts/<id> and are removed when the deployment
+// finishes or after maxArtifactAge.
+var artifacts = &artifactStore{files: map[string]string{}}
+
+type artifactStore struct {
+	mu    sync.Mutex
+	dir   string
+	files map[string]string
+}
+
+const maxArtifactAge = 2 // hours — a deployment can never outlive this
+
+// initArtifacts points the store at dir (created on demand).
+func initArtifacts(dir string) {
+	artifacts.mu.Lock()
+	defer artifacts.mu.Unlock()
+	artifacts.dir = dir
+	_ = os.MkdirAll(dir, 0o755)
+}
+
+// artifactDir returns the store root, defaulting under the build workdir.
+func artifactDir() string {
+	artifacts.mu.Lock()
+	defer artifacts.mu.Unlock()
+	if artifacts.dir != "" {
+		return artifacts.dir
+	}
+	return filepath.Join(containrWorkDir, "artifacts")
+}
+
+// putArtifact streams rc into the store and returns the artifact id.
+func putArtifact(rc io.Reader) (string, error) {
+	buf := make([]byte, 16)
+	if _, err := rand.Read(buf); err != nil {
+		return "", err
+	}
+	id := hex.EncodeToString(buf)
+	dir := artifactDir()
+	if err := os.MkdirAll(dir, 0o755); err != nil {
+		return "", err
+	}
+	path := filepath.Join(dir, id+".tar")
+	f, err := os.Create(path)
+	if err != nil {
+		return "", err
+	}
+	if _, err := io.Copy(f, rc); err != nil {
+		f.Close()
+		os.Remove(path)
+		return "", err
+	}
+	f.Close()
+
+	artifacts.mu.Lock()
+	artifacts.files[id] = path
+	artifacts.mu.Unlock()
+	return id, nil
+}
+
+// removeArtifact deletes the file and forgets the id. Safe on missing ids.
+func removeArtifact(id string) {
+	artifacts.mu.Lock()
+	path, ok := artifacts.files[id]
+	delete(artifacts.files, id)
+	artifacts.mu.Unlock()
+	if ok {
+		_ = os.Remove(path)
+		return
+	}
+	// Registered before a restart — remove best-effort by name.
+	if id != "" {
+		_ = os.Remove(filepath.Join(artifactDir(), id+".tar"))
+	}
+}
+
+// ServeArtifact streams a stored blob to a token-authenticated agent. Files
+// persist across downloads — spread builds share one context — and are
+// deleted by the deployment that created them.
+func (h *NodeAgentHandler) ServeArtifact(c *gin.Context) {
+	if !h.isValidAgentAuthToken(c.Request.Context(), agentAuthTokenFromRequest(c)) {
+		c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid auth token"})
+		return
+	}
+	id := c.Param("id")
+	raw, err := hex.DecodeString(id)
+	if len(id) != 32 || err != nil || len(raw) != 16 {
+		c.JSON(http.StatusNotFound, gin.H{"error": "Artifact not found"})
+		return
+	}
+	path := filepath.Join(artifactDir(), id+".tar")
+	info, err := os.Stat(path)
+	if err != nil || info.IsDir() {
+		c.JSON(http.StatusNotFound, gin.H{"error": "Artifact not found"})
+		return
+	}
+	c.Header("Content-Type", "application/x-tar")
+	c.File(path)
+}
+
+// purgeStaleArtifacts drops files older than maxArtifactAge. Called on boot.
+func purgeStaleArtifacts() {
+	entries, err := os.ReadDir(artifactDir())
+	if err != nil {
+		return
+	}
+	for _, e := range entries {
+		info, err := e.Info()
+		if err != nil {
+			continue
+		}
+		if info.ModTime().Before(time.Now().Add(-maxArtifactAge * time.Hour)) {
+			_ = os.Remove(filepath.Join(artifactDir(), e.Name()))
+		}
+	}
+}

app/backend/internal/api/deployments.go

@@ -5,11 +5,15 @@ import (
 	"containr/internal/deployment"
 	"containr/internal/deployqueue"
 	"containr/internal/docker"
+	"containr/internal/source"
+	"containr/internal/types"
 	"context"
 	"errors"
 	"fmt"
 	"log/slog"
 	"net/http"
+	"os"
+	"path/filepath"
 	"strings"
 	"time"
 
@@ -377,6 +381,23 @@ func runDeploymentAndSyncWithImage(
 	ctx, cancel := context.WithTimeout(parentCtx, 30*time.Minute)
 	defer cancel()
 
+	// The checkout and any shipped artifacts die with this deployment.
+	var artifactIDs []string
+	checkoutRoot := filepath.Join(containrWorkDir, "repos", dbDeployment.ID.String())
+	defer func() {
+		_ = os.RemoveAll(checkoutRoot)
+		for _, id := range artifactIDs {
+			removeArtifact(id)
+		}
+	}()
+	failDeploy := func(msg string) {
+		failedAt := time.Now()
+		_, _ = db.Exec(
+			`UPDATE deployments SET status = 'failed', error = $1, completed_at = $2, updated_at = $2 WHERE id = $3`,
+			msg, failedAt, dbDeployment.ID,
+		)
+	}
+
 	sourcePath := strings.TrimSpace(service.BuildPath)
 	if sourcePath == "" {
 		sourcePath = "."
@@ -421,19 +442,31 @@ func runDeploymentAndSyncWithImage(
 		maintURL = maintenanceURL(db)
 	}
 
-	// Node-pinned services dispatch to the agent's command queue. Builds run
-	// on the local host, so remote placement only works for registry-pulled
-	// images — git-sourced and rollback deploys fail fast with that message.
+	// Node-pinned and spread services dispatch to agent command queues.
 	nodeID := serviceNodeID(db, service.ID)
 	spread := serviceSpread(db, service.ID)
-	if (nodeID != "" || spread) && (service.GitRepo != "" || imageOverride != "") {
-		failedAt := time.Now()
-		msg := "service uses remote node placement but remote nodes only run registry-pulled images (git builds and rollbacks stay local — build-on-node is not yet supported)"
-		_, _ = db.Exec(
-			`UPDATE deployments SET status = 'failed', error = $1, completed_at = $2, updated_at = $2 WHERE id = $3`,
-			msg, failedAt, dbDeployment.ID,
-		)
-		return
+	remote := nodeID != "" || spread
+
+	// Materialize the git checkout — local builds consume it directly;
+	// remote builds package it into a context artifact the node builds.
+	if service.GitRepo != "" && imageOverride == "" {
+		var ownerID string
+		_ = db.QueryRow(`SELECT owner_id FROM projects WHERE id = $1`, service.ProjectID).Scan(&ownerID)
+		branch := req.Branch
+		if branch == "" {
+			branch = service.GitBranch
+		}
+		cloneSpec, err := resolveGitCloneSpec(db, ownerID, service.GitRepo, branch, req.CommitHash, service.BuildPath)
+		if err != nil {
+			failDeploy("resolve git source: " + err.Error())
+			return
+		}
+		src, err := source.Checkout(ctx, checkoutRoot, cloneSpec)
+		if err != nil {
+			failDeploy("git checkout: " + err.Error())
+			return
+		}
+		sourcePath = src
 	}
 
 	deployReq := &deployment.DeploymentRequest{
@@ -480,14 +513,36 @@ func runDeploymentAndSyncWithImage(
 		if image == "" {
 			image = service.Image
 		}
-		var ownerID string
-		_ = db.QueryRow(`SELECT owner_id FROM projects WHERE id = $1`, service.ProjectID).Scan(&ownerID)
-		auth := registryAuthFor(db, ownerID, image)
-		deployReq.BuildConfig = &deployment.BuildConfig{
-			BuildType:     "prebuilt",
-			PrebuiltImage: image,
-			PullUsername:  auth.Username,
-			PullPassword:  auth.Password,
+		if remote && strings.HasPrefix(image, "containr-") {
+			// Locally-built tag — no registry serves it. Ship the image
+			// itself as a docker-save artifact; the node loads it.
+			rc, err := engine.DockerClient().SaveImage(ctx, image)
+			if err != nil {
+				failDeploy("export rollback image: " + err.Error())
+				return
+			}
+			artifactID, err := putArtifact(rc)
+			_ = rc.Close()
+			if err != nil {
+				failDeploy("store rollback image artifact: " + err.Error())
+				return
+			}
+			artifactIDs = append(artifactIDs, artifactID)
+			deployReq.Config.RemoteLoad = &deployment.RemoteLoadSpec{ArtifactID: artifactID}
+			deployReq.BuildConfig = &deployment.BuildConfig{
+				BuildType:     "remote",
+				PrebuiltImage: image,
+			}
+		} else {
+			var ownerID string
+			_ = db.QueryRow(`SELECT owner_id FROM projects WHERE id = $1`, service.ProjectID).Scan(&ownerID)
+			auth := registryAuthFor(db, ownerID, image)
+			deployReq.BuildConfig = &deployment.BuildConfig{
+				BuildType:     "prebuilt",
+				PrebuiltImage: image,
+				PullUsername:  auth.Username,
+				PullPassword:  auth.Password,
+			}
 		}
 	} else {
 		// "auto" leaves BuildType empty so the manager detects it; the static
@@ -497,16 +552,54 @@ func runDeploymentAndSyncWithImage(
 		if service.Builder != "" && service.Builder != "auto" {
 			buildType = service.Builder
 		}
-		deployReq.BuildConfig = &deployment.BuildConfig{
-			BuildType:  buildType,
-			SourcePath: sourcePath,
-			Branch:     req.Branch,
-			Commit:     req.CommitHash,
-			NoCache:    req.NoCache,
-		}
+		buildArgs := map[string]string{}
+		buildCommand := ""
 		if buildType == "static" {
-			deployReq.BuildConfig.BuildCommand = firstNonEmpty(service.StaticBuildCmd, "npm ci && npm run build")
-			deployReq.BuildConfig.BuildArgs = map[string]string{"STATIC_DIR": firstNonEmpty(service.StaticDir, "dist")}
+			buildCommand = firstNonEmpty(service.StaticBuildCmd, "npm ci && npm run build")
+			buildArgs["STATIC_DIR"] = firstNonEmpty(service.StaticDir, "dist")
+		}
+		if remote {
+			// Package the context — the node docker-builds it itself.
+			packReq := &types.BuildRequest{
+				BuildType:    buildType,
+				SourcePath:   sourcePath,
+				BuildCommand: buildCommand,
+				BuildArgs:    buildArgs,
+				Environment:  env,
+			}
+			rc, err := engine.BuildManager().PackageContext(ctx, packReq)
+			if err != nil {
+				failDeploy("package build context: " + err.Error())
+				return
+			}
+			artifactID, err := putArtifact(rc)
+			_ = rc.Close()
+			if err != nil {
+				failDeploy("store build context artifact: " + err.Error())
+				return
+			}
+			artifactIDs = append(artifactIDs, artifactID)
+			deployReq.Config.RemoteBuild = &deployment.RemoteBuildSpec{
+				ArtifactID: artifactID,
+				BuildArgs:  buildArgs,
+				NoCache:    req.NoCache,
+			}
+			deployReq.BuildConfig = &deployment.BuildConfig{
+				BuildType: "remote",
+				Branch:    req.Branch,
+				Commit:    req.CommitHash,
+				NoCache:   req.NoCache,
+			}
+		} else {
+			deployReq.BuildConfig = &deployment.BuildConfig{
+				BuildType:    buildType,
+				SourcePath:   sourcePath,
+				BuildCommand: buildCommand,
+				BuildArgs:    buildArgs,
+				Branch:       req.Branch,
+				Commit:       req.CommitHash,
+				NoCache:      req.NoCache,
+			}
 		}
 	}
 

app/backend/internal/api/gitcreds.go

@@ -0,0 +1,84 @@
+package api
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"containr/internal/database"
+	"containr/internal/source"
+)
+
+// resolveGitCloneSpec turns a service's git_repo (clone URL, ssh remote, or
+// owner/repo) into a source.Spec with the project owner's provider token.
+// Public repos get no token — the clone proceeds anonymously. github_app
+// providers store the installation id, not a usable token; a fresh
+// installation token is minted per deploy.
+func resolveGitCloneSpec(db *database.DB, ownerID, gitRepo, branch, commit, buildPath string) (source.Spec, error) {
+	raw := strings.TrimSpace(gitRepo)
+	cloneURL, err := source.NormalizeCloneURL(raw)
+	if err != nil {
+		return source.Spec{}, err
+	}
+
+	spec := source.Spec{Branch: branch, Commit: commit, BuildPath: buildPath}
+
+	var providerID string
+	if !strings.Contains(cloneURL, "://") {
+		// Bare owner/repo — the connected repository row knows the host.
+		err = db.QueryRow(
+			`SELECT clone_url, provider_id FROM git_repositories
+			 WHERE full_name = $1 AND user_id = $2 LIMIT 1`,
+			cloneURL, ownerID,
+		).Scan(&cloneURL, &providerID)
+		if err != nil {
+			return source.Spec{}, fmt.Errorf("repository %s is not connected — connect it under Git settings or store a clone URL", raw)
+		}
+	} else {
+		// URL form — match a connected repo for its provider when possible;
+		// an unmatched public URL still clones, just without credentials.
+		_ = db.QueryRow(
+			`SELECT provider_id FROM git_repositories
+			 WHERE clone_url = $1 AND user_id = $2 LIMIT 1`,
+			cloneURL, ownerID,
+		).Scan(&providerID)
+	}
+
+	if err := source.ValidateRemoteURL(cloneURL); err != nil {
+		return source.Spec{}, err
+	}
+	spec.CloneURL = cloneURL
+
+	if providerID == "" {
+		return spec, nil
+	}
+	var name, apiURL, token string
+	if err := db.QueryRow(
+		`SELECT name, api_url, access_token FROM git_providers
+		 WHERE id = $1 AND user_id = $2`,
+		providerID, ownerID,
+	).Scan(&name, &apiURL, &token); err != nil {
+		return spec, nil // provider row gone — anonymous clone still works for public repos
+	}
+
+	switch strings.ToLower(name) {
+	case "github_app":
+		installationID, err := strconv.ParseInt(strings.TrimSpace(token), 10, 64)
+		if err == nil && installationID > 0 {
+			if minted, err := getGitHubAppInstallationToken(apiURL, installationID); err == nil {
+				spec.Token = minted
+				spec.User = "x-access-token"
+			}
+		}
+	case "gitlab":
+		spec.Token = token
+		spec.User = "oauth2"
+	case "bitbucket":
+		spec.Token = token
+		spec.User = "x-token-auth"
+	default:
+		spec.Token = token
+		spec.User = "x-access-token"
+	}
+	return spec, nil
+}

app/backend/internal/api/noderunner.go

@@ -157,6 +157,45 @@ func (r *agentNodeRunner) reconcileOnAgents(ctx context.Context, spec deployment
 		})
 	}
 
+	// Ship the image to every distinct target agent before replicas start.
+	// RemoteBuild nodes docker-build from the packaged context artifact;
+	// RemoteLoad nodes docker-load a saved tarball (local-tag rollbacks).
+	// Registry-pullable images skip this — docker run pulls on demand.
+	if spec.RemoteBuild != nil || spec.RemoteLoad != nil {
+		seen := map[string]bool{}
+		for i := 0; i < replicas; i++ {
+			agentID := targetFor(i)
+			if seen[agentID] {
+				continue
+			}
+			seen[agentID] = true
+			if spec.RemoteBuild != nil {
+				buildArgs := map[string]interface{}{}
+				for k, v := range spec.RemoteBuild.BuildArgs {
+					buildArgs[k] = v
+				}
+				_, err := r.enqueueAndWaitTimeout(ctx, agentID, "", "build_image",
+					map[string]interface{}{
+						"artifact_id": spec.RemoteBuild.ArtifactID,
+						"image":       spec.Image,
+						"build_args":  buildArgs,
+						"no_cache":    spec.RemoteBuild.NoCache,
+					}, 25*time.Minute)
+				if err != nil {
+					return nil, fmt.Errorf("build image on node %s: %w", agentID, err)
+				}
+			} else if spec.RemoteLoad != nil {
+				_, err := r.enqueueAndWaitTimeout(ctx, agentID, "", "load_image",
+					map[string]interface{}{
+						"artifact_id": spec.RemoteLoad.ArtifactID,
+					}, 10*time.Minute)
+				if err != nil {
+					return nil, fmt.Errorf("load image on node %s: %w", agentID, err)
+				}
+			}
+		}
+	}
+
 	state := &deployment.RuntimeState{Desired: replicas, Status: "running"}
 	for i := 0; i < replicas; i++ {
 		agentID := targetFor(i)
@@ -375,6 +414,10 @@ func (r *agentNodeRunner) RetireService(ctx context.Context, serviceID string) e
 // poll on their own interval (≥5s), so this blocks — it runs inside the
 // deploy queue worker, never on a request path.
 func (r *agentNodeRunner) enqueueAndWait(ctx context.Context, agentID, containerID, cmdType string, payload map[string]interface{}) (string, error) {
+	return r.enqueueAndWaitTimeout(ctx, agentID, containerID, cmdType, payload, 8*time.Minute)
+}
+
+func (r *agentNodeRunner) enqueueAndWaitTimeout(ctx context.Context, agentID, containerID, cmdType string, payload map[string]interface{}, timeout time.Duration) (string, error) {
 	var cid sql.NullString
 	if containerID != "" {
 		cid = sql.NullString{String: containerID, Valid: true}
@@ -390,7 +433,7 @@ func (r *agentNodeRunner) enqueueAndWait(ctx context.Context, agentID, container
 		return "", err
 	}
 
-	deadline := time.Now().Add(8 * time.Minute) // image pulls on a cold node
+	deadline := time.Now().Add(timeout) // image pulls/builds on a cold node
 	for {
 		row, err := r.q.GetCommandForAgent(ctx, sqlcdb.GetCommandForAgentParams{
 			ID:          cmd.ID,

app/backend/internal/api/routes.go

@@ -5,6 +5,7 @@ import (
 	"log"
 	"net/http"
 	"os"
+	"path/filepath"
 	"time"
 
 	"containr/internal/build"
@@ -43,6 +44,8 @@ func SetupRoutes(router *gin.Engine, db *database.DB, redis *database.Redis, cfg
 		dockerClient = client
 		buildManager = build.NewBuildManager("/tmp/containr-builds", dockerClient)
 		deploymentEngine = deployment.NewDeploymentEngine(buildManager, dockerClient)
+		initArtifacts(filepath.Join("/tmp/containr-builds", "artifacts"))
+		purgeStaleArtifacts()
 		// Node-pinned services dispatch container lifecycle to the agent's
 		// command queue instead of the local Docker socket.
 		deploymentEngine.SetNodeRunner(newAgentNodeRunner(db))

app/backend/internal/build/dockerfile.go

@@ -539,12 +539,16 @@ func createBuildContext(sourcePath, dockerfileContent string) (io.ReadCloser, er
 		return nil, err
 	}
 
-	// Add source files to tar
+	// Add source files to tar. The checkout's .git metadata is never build
+	// context — it bloats the tar and ships clone URLs to remote daemons.
 	err = filepath.Walk(sourcePath, func(file string, fi os.FileInfo, err error) error {
 		if err != nil {
 			return err
 		}
 		if fi.IsDir() {
+			if fi.Name() == ".git" {
+				return filepath.SkipDir
+			}
 			return nil
 		}
 

app/backend/internal/build/manager.go

@@ -3,6 +3,8 @@ package build
 import (
 	"context"
 	"fmt"
+	"io"
+	"os"
 	"path/filepath"
 	"time"
 
@@ -92,6 +94,75 @@ func (bm *BuildManager) Build(ctx context.Context, req *types.BuildRequest) (*ty
 	}
 }
 
+// PackageContext produces the same build-context tar Build would hand the
+// local daemon, without building it. Node agents download the tar and run
+// docker build themselves — the Dockerfile lands at the tar root.
+func (bm *BuildManager) PackageContext(ctx context.Context, req *types.BuildRequest) (io.ReadCloser, error) {
+	if req.BuildType == "" {
+		detectedType, err := bm.DetectBuildType(ctx, req.SourcePath)
+		if err != nil {
+			return nil, fmt.Errorf("failed to detect build type: %w", err)
+		}
+		req.BuildType = string(detectedType)
+	}
+
+	var dockerfileContent string
+	switch BuildType(req.BuildType) {
+	case BuildTypeDockerfile:
+		name, err := bm.dockerfileBuilder.DetectDockerfile(ctx, req.SourcePath)
+		if err != nil {
+			return nil, fmt.Errorf("failed to detect Dockerfile: %w", err)
+		}
+		path := filepath.Join(req.SourcePath, name)
+		if optimized, err := bm.dockerfileBuilder.OptimizeDockerfile(ctx, path); err == nil {
+			path = optimized
+		}
+		data, err := os.ReadFile(path)
+		if err != nil {
+			return nil, fmt.Errorf("failed to read Dockerfile: %w", err)
+		}
+		dockerfileContent = string(data)
+	case BuildTypeRailpack:
+		if err := bm.railpackBuilder.DetectRailpack(ctx, req.SourcePath); err != nil {
+			return nil, fmt.Errorf("Railpack cannot build this project: %w", err)
+		}
+		content, err := bm.railpackBuilder.generateDockerfile(ctx, req.SourcePath, &RailpackConfig{
+			BuildCmd: req.BuildCommand,
+			StartCmd: req.StartCommand,
+			Env:      req.Environment,
+		})
+		if err != nil {
+			return nil, fmt.Errorf("failed to generate Dockerfile with Railpack: %w", err)
+		}
+		dockerfileContent = content
+	case BuildTypeNixpacks:
+		plan, err := bm.nixpacksBuilder.GeneratePlan(ctx, req.SourcePath, &NixpacksConfig{
+			BuildCmd: req.BuildCommand,
+			StartCmd: req.StartCommand,
+			Env:      req.Environment,
+		})
+		if err != nil {
+			return nil, fmt.Errorf("failed to generate build plan: %w", err)
+		}
+		path, err := bm.nixpacksBuilder.generateDockerfile(plan)
+		if err != nil {
+			return nil, fmt.Errorf("failed to generate Dockerfile: %w", err)
+		}
+		defer os.Remove(path)
+		data, err := os.ReadFile(path)
+		if err != nil {
+			return nil, fmt.Errorf("failed to read generated Dockerfile: %w", err)
+		}
+		dockerfileContent = string(data)
+	case BuildTypeStatic:
+		dockerfileContent = staticDockerfile
+	default:
+		return nil, fmt.Errorf("unsupported build type for remote packaging: %s", req.BuildType)
+	}
+
+	return createBuildContext(req.SourcePath, dockerfileContent)
+}
+
 // buildPrebuilt handles prebuilt image deployments
 func (bm *BuildManager) buildPrebuilt(ctx context.Context, req *types.BuildRequest) (*types.BuildResponse, error) {
 	if req.PrebuiltImage == "" {

app/backend/internal/build/nixpacks.go

@@ -476,17 +476,22 @@ func (n *NixpacksBuilder) Build(ctx context.Context, req *types.BuildRequest) (*
 	}
 
 	// Create temporary Dockerfile
-	dockerfile, err := n.generateDockerfile(plan)
+	dockerfilePath, err := n.generateDockerfile(plan)
 	if err != nil {
 		return nil, fmt.Errorf("failed to generate Dockerfile: %w", err)
 	}
-	defer os.Remove(dockerfile)
+	defer os.Remove(dockerfilePath)
 
 	// Build Docker image
 	imageName := fmt.Sprintf("%s:%s", req.ImageName, req.ImageTag)
 
-	// Create build context tar
-	buildCtx, err := createBuildContext(req.SourcePath, dockerfile)
+	// Create build context tar — createBuildContext takes the Dockerfile
+	// contents, not its path.
+	dockerfileData, err := os.ReadFile(dockerfilePath)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read generated Dockerfile: %w", err)
+	}
+	buildCtx, err := createBuildContext(req.SourcePath, string(dockerfileData))
 	if err != nil {
 		return nil, fmt.Errorf("failed to create build context: %w", err)
 	}

app/backend/internal/deployment/engine.go

@@ -95,12 +95,29 @@ type ServiceConfig struct {
 	// reuses it so public URLs survive restarts. 0 = pick ephemeral.
 	PublishedPort int32 `json:"published_port,omitempty"`
 	// NodeID pins the service to a registered node agent; "" = local Docker
-	// host. Remote placement requires a registry-pullable image — builds stay
-	// on the local host (build-on-node is not yet supported).
+	// host.
 	NodeID string `json:"node_id,omitempty"`
 	// Spread distributes replicas across every online, schedulable agent.
-	// Same registry-image constraint as NodeID.
 	Spread bool `json:"spread,omitempty"`
+	// RemoteBuild, when set, makes each target node docker-build the image
+	// itself from a packaged context artifact instead of pulling a registry
+	// tag. The image name comes from the deployment, not the spec.
+	RemoteBuild *RemoteBuildSpec `json:"remote_build,omitempty"`
+	// RemoteLoad ships a docker-save tarball to each target node — used for
+	// rollbacks of locally-built tags that no registry can serve.
+	RemoteLoad *RemoteLoadSpec `json:"remote_load,omitempty"`
+}
+
+// RemoteBuildSpec is the agent-side docker build request.
+type RemoteBuildSpec struct {
+	ArtifactID string            `json:"artifact_id"`
+	BuildArgs  map[string]string `json:"build_args,omitempty"`
+	NoCache    bool              `json:"no_cache,omitempty"`
+}
+
+// RemoteLoadSpec asks the agent to docker-load an image tarball artifact.
+type RemoteLoadSpec struct {
+	ArtifactID string `json:"artifact_id"`
 }
 
 type PortMapping struct {
@@ -211,6 +228,12 @@ func (de *DeploymentEngine) DockerClient() *docker.Client {
 	return de.dockerClient
 }
 
+// BuildManager exposes the engine's builders for context packaging — remote
+// nodes build the tar this produces themselves.
+func (de *DeploymentEngine) BuildManager() *build.BuildManager {
+	return de.buildManager
+}
+
 // SetNodeRunner wires remote-node dispatch for services pinned to an agent.
 func (de *DeploymentEngine) SetNodeRunner(r NodeRunner) {
 	de.nodeRunner = r
@@ -326,11 +349,19 @@ func (de *DeploymentEngine) executeDeployment(ctx context.Context, deployment *D
 	})
 }
 
-// buildImage builds the container image
+// buildImage builds the container image. "remote" build types produce no
+// local image — the target node builds or loads it from an artifact; the
+// deployment still needs a deterministic tag so every node names it alike.
 func (de *DeploymentEngine) buildImage(ctx context.Context, deployment *Deployment, buildConfig *BuildConfig) (string, error) {
 	if buildConfig == nil {
 		return "", fmt.Errorf("build config is required")
 	}
+	if buildConfig.BuildType == "remote" {
+		if buildConfig.PrebuiltImage != "" {
+			return buildConfig.PrebuiltImage, nil
+		}
+		return fmt.Sprintf("containr-%s-%s:%s", deployment.ServiceID, deployment.Environment, deployment.ID), nil
+	}
 
 	buildReq := &types.BuildRequest{
 		BuildType:     buildConfig.BuildType,
@@ -393,6 +424,8 @@ func (de *DeploymentEngine) deployService(ctx context.Context, deployment *Deplo
 		BasicAuthUsers: cfg.BasicAuthUsers,
 		NodeID:         cfg.NodeID,
 		Spread:         cfg.Spread,
+		RemoteBuild:    cfg.RemoteBuild,
+		RemoteLoad:     cfg.RemoteLoad,
 	}
 	for _, pm := range cfg.PortMappings {
 		if spec.Port == 0 {

app/backend/internal/deployment/runtime.go

@@ -63,6 +63,12 @@ type RuntimeSpec struct {
 	// PlacementTags restricts auto/spread candidates to agents carrying
 	// every listed tag. An explicit NodeID pin bypasses tag filtering.
 	PlacementTags []string
+	// RemoteBuild makes target nodes docker-build Image from a packaged
+	// context artifact before replicas start (git-sourced remote deploys).
+	RemoteBuild *RemoteBuildSpec
+	// RemoteLoad makes target nodes docker-load a saved image tarball —
+	// remote rollbacks of locally-built tags.
+	RemoteLoad *RemoteLoadSpec
 }
 
 // RuntimeContainer describes one live replica.

app/backend/internal/docker/client.go

@@ -336,6 +336,13 @@ func (c *Client) BuildImage(ctx context.Context, buildContext io.Reader, options
 	return resp, nil
 }
 
+// SaveImage streams refs as a docker-save tarball. Remote nodes receive
+// these through the artifact endpoint and docker load them — that is how
+// locally-built rollback tags reach nodes without a registry.
+func (c *Client) SaveImage(ctx context.Context, refs ...string) (io.ReadCloser, error) {
+	return c.cli.ImageSave(ctx, refs)
+}
+
 // RemoveImage removes an image
 func (c *Client) RemoveImage(ctx context.Context, imageID string, force bool) ([]image.DeleteResponse, error) {
 	return c.cli.ImageRemove(ctx, imageID, image.RemoveOptions{

app/backend/internal/source/source.go

@@ -0,0 +1,190 @@
+// Package source materializes git checkouts for builds. Services reference
+// a repository by URL (or owner/repo); deployments fetch the exact branch or
+// commit into an isolated workdir, then point the builders at build_path
+// inside it. Credentials travel through GIT_ASKPASS so tokens never land in
+// argv, .git/config, logs, or the build context.
+package source
+
+import (
+	"context"
+	"fmt"
+	"net/url"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+)
+
+// Spec describes one checkout.
+type Spec struct {
+	CloneURL  string // https URL (NormalizeCloneURL output); local paths allowed for tests
+	Branch    string // ref to fetch when Commit is empty
+	Commit    string // optional SHA pinned over Branch
+	BuildPath string // subdirectory inside the repo; "" or "." = repo root
+	Token     string // optional http credential
+	User      string // credential username; defaults per provider in ResolveUser
+}
+
+// NormalizeCloneURL converts the forms services store into an https clone
+// URL: ssh remotes (git@host:org/repo, ssh://git@host/org/repo) map onto
+// https so token auth works uniformly. A bare "owner/repo" is returned
+// unchanged — the caller resolves the host through git_repositories.
+func NormalizeCloneURL(raw string) (string, error) {
+	raw = strings.TrimSpace(raw)
+	if raw == "" {
+		return "", fmt.Errorf("empty repository reference")
+	}
+	// scp-style ssh remote: [email protected]:org/repo(.git)
+	if strings.HasPrefix(raw, "git@") && strings.Contains(raw, ":") {
+		host := raw[len("git@"):strings.Index(raw, ":")]
+		path := strings.TrimPrefix(raw[strings.Index(raw, ":")+1:], "/")
+		return "https://" + host + "/" + path, nil
+	}
+	if strings.HasPrefix(raw, "ssh://") {
+		u, err := url.Parse(raw)
+		if err != nil {
+			return "", fmt.Errorf("invalid ssh remote %q", raw)
+		}
+		return "https://" + u.Host + u.Path, nil
+	}
+	if strings.HasPrefix(raw, "http://") || strings.HasPrefix(raw, "https://") {
+		return raw, nil
+	}
+	if strings.Contains(raw, "://") {
+		return "", fmt.Errorf("unsupported repository scheme in %q", raw)
+	}
+	if strings.Count(raw, "/") == 1 && !strings.ContainsAny(raw, " @:") {
+		return raw, nil // owner/repo — resolved against git_repositories upstream
+	}
+	return "", fmt.Errorf("unsupported repository reference %q", raw)
+}
+
+// ValidateRemoteURL rejects non-http(s) clones before a deploy accepts them.
+// Local checkouts (tests, mounted workspaces) bypass this via Checkout.
+func ValidateRemoteURL(cloneURL string) error {
+	if strings.HasPrefix(cloneURL, "http://") || strings.HasPrefix(cloneURL, "https://") {
+		return nil
+	}
+	return fmt.Errorf("clone URL must be http(s), got %q", cloneURL)
+}
+
+// Checkout fetches spec into destDir/repo and returns the directory the
+// builders should consume (checkout root + build_path). Callers
+// RemoveAll(destDir) — the checkout is a per-deployment workspace, never
+// shared. The askpass helper lives outside repo so it can't leak into the
+// build context.
+func Checkout(ctx context.Context, destDir string, spec Spec) (string, error) {
+	repoDir := filepath.Join(destDir, "repo")
+	if err := os.MkdirAll(repoDir, 0o755); err != nil {
+		return "", err
+	}
+
+	env := append(os.Environ(), "GIT_TERMINAL_PROMPT=0")
+	if spec.Token != "" {
+		// Askpass keeps the token out of argv and .git/config.
+		askpass := filepath.Join(destDir, ".git-askpass")
+		script := "#!/bin/sh\ncase \"$1\" in\n*sername*) printf '%s' \"$CONTAINR_GIT_USER\" ;;\n*) printf '%s' \"$CONTAINR_GIT_TOKEN\" ;;\nesac\n"
+		if err := os.WriteFile(askpass, []byte(script), 0o700); err != nil {
+			return "", fmt.Errorf("write askpass: %w", err)
+		}
+		user := spec.User
+		if user == "" {
+			user = "x-access-token"
+		}
+		env = append(env,
+			"GIT_ASKPASS="+askpass,
+			"CONTAINR_GIT_USER="+user,
+			"CONTAINR_GIT_TOKEN="+spec.Token,
+		)
+	}
+
+	run := func(args ...string) error {
+		cmd := exec.CommandContext(ctx, "git", args...)
+		cmd.Dir = repoDir
+		cmd.Env = env
+		out, err := cmd.CombinedOutput()
+		if err != nil {
+			return fmt.Errorf("git %s: %s", args[0], strings.TrimSpace(string(out)))
+		}
+		return nil
+	}
+
+	if err := run("init", "-q"); err != nil {
+		return "", err
+	}
+	if err := run("remote", "add", "origin", spec.CloneURL); err != nil {
+		return "", err
+	}
+
+	ref := spec.Commit
+	if ref == "" {
+		ref = spec.Branch
+	}
+	if ref == "" {
+		ref = "HEAD"
+	}
+	// Cheap path first, widening on failure: dumb transports reject
+	// --depth outright, and some hosts refuse direct SHA fetches so a
+	// pinned commit may only be reachable through its branch.
+	attempts := [][]string{
+		{"fetch", "--depth", "1", "origin", ref},
+		{"fetch", "origin", ref},
+	}
+	if spec.Commit != "" {
+		branchRef := spec.Branch
+		if branchRef == "" {
+			branchRef = "HEAD"
+		}
+		attempts = append(attempts,
+			[]string{"fetch", "--depth", "100", "origin", branchRef},
+			[]string{"fetch", "origin", branchRef},
+		)
+	}
+	var fetchErr error
+	for _, args := range attempts {
+		if fetchErr = run(args...); fetchErr == nil {
+			break
+		}
+	}
+	if fetchErr != nil {
+		return "", fetchErr
+	}
+	if err := run("checkout", "-q", spec.CommitOrFetchHead()); err != nil {
+		return "", err
+	}
+
+	return ResolveBuildPath(repoDir, spec.BuildPath)
+}
+
+// CommitOrFetchHead is the checkout target: the pinned commit or FETCH_HEAD.
+func (s Spec) CommitOrFetchHead() string {
+	if s.Commit != "" {
+		return s.Commit
+	}
+	return "FETCH_HEAD"
+}
+
+// ResolveBuildPath maps build_path onto the checkout and rejects escapes —
+// a path like ../../etc must never leave the workspace.
+func ResolveBuildPath(checkoutDir, buildPath string) (string, error) {
+	bp := strings.TrimSpace(buildPath)
+	if bp == "" || bp == "." {
+		return checkoutDir, nil
+	}
+	if filepath.IsAbs(bp) {
+		return "", fmt.Errorf("build_path must be relative, got %q", bp)
+	}
+	clean := filepath.Clean(bp)
+	if clean == ".." || strings.HasPrefix(clean, ".."+string(filepath.Separator)) {
+		return "", fmt.Errorf("build_path escapes the checkout: %q", bp)
+	}
+	resolved := filepath.Join(checkoutDir, clean)
+	info, err := os.Stat(resolved)
+	if err != nil {
+		return "", fmt.Errorf("build_path %q not found in checkout", bp)
+	}
+	if !info.IsDir() {
+		return "", fmt.Errorf("build_path %q is not a directory", bp)
+	}
+	return resolved, nil
+}

app/backend/internal/source/source_test.go

@@ -0,0 +1,152 @@
+package source
+
+import (
+	"context"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"testing"
+)
+
+func TestNormalizeCloneURL(t *testing.T) {
+	cases := []struct {
+		in, want string
+		err      bool
+	}{
+		{"https://github.com/org/repo.git", "https://github.com/org/repo.git", false},
+		{"[email protected]:org/repo.git", "https://github.com/org/repo.git", false},
+		{"ssh://[email protected]/org/repo.git", "https://gitlab.example.com/org/repo.git", false},
+		{"org/repo", "org/repo", false},
+		{"  https://gitlab.com/a/b.git  ", "https://gitlab.com/a/b.git", false},
+		{"", "", true},
+		{"ftp://example.com/repo", "", true},
+		{"weird string", "", true},
+	}
+	for _, c := range cases {
+		got, err := NormalizeCloneURL(c.in)
+		if c.err {
+			if err == nil {
+				t.Errorf("%q: expected error, got %q", c.in, got)
+			}
+			continue
+		}
+		if err != nil {
+			t.Errorf("%q: unexpected error %v", c.in, err)
+			continue
+		}
+		if got != c.want {
+			t.Errorf("%q: got %q, want %q", c.in, got, c.want)
+		}
+	}
+}
+
+func TestValidateRemoteURL(t *testing.T) {
+	if err := ValidateRemoteURL("https://github.com/o/r.git"); err != nil {
+		t.Errorf("https should pass: %v", err)
+	}
+	if err := ValidateRemoteURL("file:///tmp/repo"); err == nil {
+		t.Error("file:// should be rejected")
+	}
+	if err := ValidateRemoteURL("/tmp/repo"); err == nil {
+		t.Error("local path should be rejected")
+	}
+}
+
+// initRepo creates a small git repo with a branch and returns its path.
+func initRepo(t *testing.T) string {
+	t.Helper()
+	dir := t.TempDir()
+	run := func(args ...string) {
+		t.Helper()
+		cmd := exec.Command("git", args...)
+		cmd.Dir = dir
+		cmd.Env = append(os.Environ(),
+			"GIT_AUTHOR_NAME=t", "GIT_AUTHOR_EMAIL=t@t",
+			"GIT_COMMITTER_NAME=t", "GIT_COMMITTER_EMAIL=t@t")
+		if out, err := cmd.CombinedOutput(); err != nil {
+			t.Fatalf("git %v: %s", args, out)
+		}
+	}
+	run("init", "-q", "-b", "main")
+	if err := os.WriteFile(filepath.Join(dir, "app.txt"), []byte("v1"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.MkdirAll(filepath.Join(dir, "sub"), 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(filepath.Join(dir, "sub", "inner.txt"), []byte("sub"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	run("add", ".")
+	run("commit", "-q", "-m", "first")
+	return dir
+}
+
+func TestCheckoutBranch(t *testing.T) {
+	if _, err := exec.LookPath("git"); err != nil {
+		t.Skip("git not available")
+	}
+	repo := initRepo(t)
+	dest := t.TempDir()
+	dir, err := Checkout(context.Background(), dest, Spec{CloneURL: repo, Branch: "main"})
+	if err != nil {
+		t.Fatalf("checkout: %v", err)
+	}
+	if _, err := os.Stat(filepath.Join(dir, "app.txt")); err != nil {
+		t.Errorf("expected app.txt in checkout: %v", err)
+	}
+}
+
+func TestCheckoutBuildPath(t *testing.T) {
+	if _, err := exec.LookPath("git"); err != nil {
+		t.Skip("git not available")
+	}
+	repo := initRepo(t)
+	dest := t.TempDir()
+	dir, err := Checkout(context.Background(), dest, Spec{CloneURL: repo, Branch: "main", BuildPath: "sub"})
+	if err != nil {
+		t.Fatalf("checkout: %v", err)
+	}
+	if filepath.Base(dir) != "sub" {
+		t.Errorf("expected sub build path, got %s", dir)
+	}
+	if _, err := os.Stat(filepath.Join(dir, "inner.txt")); err != nil {
+		t.Errorf("expected inner.txt under build path: %v", err)
+	}
+}
+
+func TestCheckoutCommit(t *testing.T) {
+	if _, err := exec.LookPath("git"); err != nil {
+		t.Skip("git not available")
+	}
+	repo := initRepo(t)
+	out, err := exec.Command("git", "-C", repo, "rev-parse", "HEAD").Output()
+	if err != nil {
+		t.Fatal(err)
+	}
+	sha := string(out[:len(out)-1])
+	dest := t.TempDir()
+	dir, err := Checkout(context.Background(), dest, Spec{CloneURL: repo, Commit: sha, Branch: "main"})
+	if err != nil {
+		t.Fatalf("checkout commit: %v", err)
+	}
+	if _, err := os.Stat(filepath.Join(dir, "app.txt")); err != nil {
+		t.Errorf("expected app.txt in pinned checkout: %v", err)
+	}
+}
+
+func TestResolveBuildPathEscapes(t *testing.T) {
+	root := t.TempDir()
+	if _, err := ResolveBuildPath(root, "../../etc"); err == nil {
+		t.Error("escape should be rejected")
+	}
+	if _, err := ResolveBuildPath(root, "/abs/path"); err == nil {
+		t.Error("absolute path should be rejected")
+	}
+	if _, err := ResolveBuildPath(root, "missing"); err == nil {
+		t.Error("missing dir should be rejected")
+	}
+	if got, err := ResolveBuildPath(root, "."); err != nil || got != root {
+		t.Errorf("dot should resolve to root, got %q err=%v", got, err)
+	}
+}