refactor(build): improve err when file specified by -f does not exist

When the user specifies a Containerfile or Dockfile with the -f flag in podman build, if the file does not exist, the error should be intuitive to the user.

Fixed: containers#22940

Signed-off-by: Kevin Cui <bh@bugs.cc>

cmd/podman/common/build.go

@@ -202,10 +202,7 @@ func ParseBuildOpts(cmd *cobra.Command, args []string, buildOpts *BuildFlagsWrap
 		// No context directory or URL was specified.  Try to use the home of
 		// the first locally-available Containerfile.
 		for i := range containerFiles {
-			if strings.HasPrefix(containerFiles[i], "http://") ||
-				strings.HasPrefix(containerFiles[i], "https://") ||
-				strings.HasPrefix(containerFiles[i], "git://") ||
-				strings.HasPrefix(containerFiles[i], "github.com/") {
+			if isURL(containerFiles[i]) {
 				continue
 			}
 			absFile, err := filepath.Abs(containerFiles[i])
@@ -241,6 +238,10 @@ func ParseBuildOpts(cmd *cobra.Command, args []string, buildOpts *BuildFlagsWrap
 		}
 	}
 
+	if err := areContainerfilesValid(contextDir, containerFiles); err != nil {
+		return nil, err
+	}
+
 	var logFile *os.File
 	if cmd.Flag("logfile").Changed {
 		var err error
@@ -628,3 +629,41 @@ func parseDockerignore(ignoreFile string) ([]string, error) {
 	}
 	return excludes, nil
 }
+
+func areContainerfilesValid(contextDir string, containerFiles []string) error {
+	for _, f := range containerFiles {
+		if isURL(f) || f == "/dev/stdin" {
+			continue
+		}
+
+		// Because currently podman runs the test/bud.bats tests under the buildah project in CI,
+		// the following error messages need to be consistent with buildah; otherwise, the podman CI will fail.
+		// See: https://github.com/containers/buildah/blob/4c781b59b49d66e07324566555339888113eb7e2/imagebuildah/build.go#L139-L141
+		// 	    https://github.com/containers/buildah/blob/4c781b59b49d66e07324566555339888113eb7e2/tests/bud.bats#L3474-L3479
+		if utils.IsDir(f) {
+			return fmt.Errorf("containerfile: %q cannot be path to a directory", f)
+		}
+
+		// If the file is not found, try again with context directory prepended (if not prepended yet)
+		// Ref: https://github.com/containers/buildah/blob/4c781b59b49d66e07324566555339888113eb7e2/imagebuildah/build.go#L125-L135
+		if utils.FileExists(f) {
+			continue
+		}
+		if !strings.HasPrefix(f, contextDir) {
+			if utils.FileExists(filepath.Join(contextDir, f)) {
+				continue
+			}
+		}
+
+		return fmt.Errorf("the specified Containerfile or Dockerfile does not exist, %s: %w", f, syscall.ENOENT)
+	}
+
+	return nil
+}
+
+func isURL(s string) bool {
+	return strings.HasPrefix(s, "http://") ||
+		strings.HasPrefix(s, "https://") ||
+		strings.HasPrefix(s, "git://") ||
+		strings.HasPrefix(s, "github.com/")
+}

test/e2e/build_test.go

@@ -94,6 +94,25 @@ var _ = Describe("Podman build", func() {
 		Expect(session).Should(ExitCleanly())
 	})
 
+	It("podman build with not found Containerfile or Dockerfile", func() {
+		targetPath := filepath.Join(podmanTest.TempDir, "notfound")
+		err = os.Mkdir(targetPath, 0755)
+		Expect(err).ToNot(HaveOccurred())
+		defer func() {
+			Expect(os.RemoveAll(targetPath)).To(Succeed())
+		}()
+
+		session := podmanTest.Podman([]string{"build", targetPath})
+		session.WaitWithDefaultTimeout()
+		expectStderr := fmt.Sprintf("no Containerfile or Dockerfile specified or found in context directory, %s", targetPath)
+		Expect(session).Should(ExitWithError(125, expectStderr))
+
+		session = podmanTest.Podman([]string{"build", "-f", "foo", targetPath})
+		session.WaitWithDefaultTimeout()
+		expectStderr = fmt.Sprintf("the specified Containerfile or Dockerfile does not exist, %s", "foo")
+		Expect(session).Should(ExitWithError(125, expectStderr))
+	})
+
 	It("podman build with logfile", func() {
 		logfile := filepath.Join(podmanTest.TempDir, "logfile")
 		session := podmanTest.Podman([]string{"build", "--pull=never", "--tag", "test", "--logfile", logfile, "build/basicalpine"})