Add skip-path Feature for Dependency Mirror

postal/internal/dependency_mirror.go

@@ -17,8 +17,44 @@ func NewDependencyMirrorResolver(bindingResolver BindingResolver) DependencyMirr
 	}
 }
 
+// Parses a raw mirror string into a map of arguments.
+func getMirrorArgs(mirror string) map[string]string {
+
+	mirrorArgs := map[string]string{
+		"mirror":    mirror,
+		"skip-path": "",
+	}
+
+	// Split mirror string at commas and extract specified arguments.
+	for _, arg := range strings.Split(mirror, ",") {
+		argPair := strings.SplitN(arg, "=", 2)
+		// If a URI is provided without the key 'mirror=', still treat it as the 'mirror' argument.
+		// This addresses backwards compatibility and user experience as most mirrors won't need any additional arguments.
+		if len(argPair) == 1 && (strings.HasPrefix(argPair[0], "https") || strings.HasPrefix(argPair[0], "file")) {
+			mirrorArgs["mirror"] = argPair[0]
+		}
+		// Add all provided arguments to key/value map.
+		if len(argPair) == 2 {
+			mirrorArgs[argPair[0]] = argPair[1]
+		}
+	}
+
+	// Unescape mirror arguments to support URL-encoded strings.
+	tmp, err := url.PathUnescape(mirrorArgs["mirror"])
+	if err == nil {
+		mirrorArgs["mirror"] = tmp
+	}
+	tmp, err = url.PathUnescape(mirrorArgs["skip-path"])
+	if err == nil {
+		mirrorArgs["skip-path"] = tmp
+	}
+
+	return mirrorArgs
+}
+
 func formatAndVerifyMirror(mirror, uri string) (string, error) {
-	mirrorURL, err := url.Parse(mirror)
+	mirrorArgs := getMirrorArgs(mirror)
+	mirrorURL, err := url.Parse(mirrorArgs["mirror"])
 	if err != nil {
 		return "", err
 	}
@@ -32,7 +68,7 @@ func formatAndVerifyMirror(mirror, uri string) (string, error) {
 		return "", fmt.Errorf("invalid mirror scheme")
 	}
 
-	mirrorURL.Path = strings.Replace(mirrorURL.Path, "{originalHost}", uriURL.Hostname(), 1) + uriURL.Path
+	mirrorURL.Path = strings.Replace(mirrorURL.Path, "{originalHost}", uriURL.Hostname(), 1) + strings.Replace(uriURL.Path, mirrorArgs["skip-path"], "", 1)
 	return mirrorURL.String(), nil
 }
 

postal/internal/dependency_mirror_test.go

@@ -123,6 +123,73 @@ func testDependencyMirror(t *testing.T, context spec.G, it spec.S) {
 			})
 		})
 
+		context("via binding with additional arguments", func() {
+			it.Before(func() {
+				tmpDir, err = os.MkdirTemp("", "dependency-mirror")
+				Expect(err).NotTo(HaveOccurred())
+				Expect(os.WriteFile(filepath.Join(tmpDir, "type"), []byte("dependency-mirror"), os.ModePerm))
+
+				bindingResolver = &fakes.BindingResolver{}
+				resolver = internal.NewDependencyMirrorResolver(bindingResolver)
+
+				bindingResolver.ResolveCall.Returns.BindingSlice = []servicebindings.Binding{
+					{
+						Name: "some-binding",
+						Path: "some-path",
+						Type: "dependency-mirror",
+						Entries: map[string]*servicebindings.Entry{
+							"default": servicebindings.NewEntry(filepath.Join(tmpDir, "default")),
+						},
+					},
+				}
+			})
+
+			it.After(func() {
+				Expect(os.RemoveAll(tmpDir)).To(Succeed())
+			})
+
+			context("respects skip-path argument", func() {
+				it.Before(func() {
+					Expect(os.WriteFile(filepath.Join(tmpDir, "github.com"), []byte("mirror=https://mirror.example.org/public-github,skip-path=/path-to-skip"), os.ModePerm))
+					Expect(os.WriteFile(filepath.Join(tmpDir, "nodejs.org"), []byte("https://mirror.example.org/node-dist,skip-path=/path-to-skip"), os.ModePerm))
+					Expect(os.WriteFile(filepath.Join(tmpDir, "maven.org"), []byte("https://user%3Apa%24%24word%2C%40mirror.example.org%2Fmaven,skip-path=%2Fpath%20to%20skip"), os.ModePerm))
+
+					bindingResolver.ResolveCall.Returns.BindingSlice[0].Entries = map[string]*servicebindings.Entry{
+						"github.com": servicebindings.NewEntry(filepath.Join(tmpDir, "github.com")),
+						"nodejs.org": servicebindings.NewEntry(filepath.Join(tmpDir, "nodejs.org")),
+						"maven.org":  servicebindings.NewEntry(filepath.Join(tmpDir, "maven.org")),
+					}
+				})
+
+				it("sets mirror excluding a path segment with 'mirror' argument", func() {
+					boundDependency, err := resolver.FindDependencyMirror("https://github.com/path-to-skip/dep.tgz", "some-platform-dir")
+					Expect(err).ToNot(HaveOccurred())
+					Expect(bindingResolver.ResolveCall.Receives.Typ).To(Equal("dependency-mirror"))
+					Expect(bindingResolver.ResolveCall.Receives.Provider).To(BeEmpty())
+					Expect(bindingResolver.ResolveCall.Receives.PlatformDir).To(Equal("some-platform-dir"))
+					Expect(boundDependency).To(Equal("https://mirror.example.org/public-github/dep.tgz"))
+				})
+
+				it("sets mirror excluding a path segment without 'mirror' argument", func() {
+					boundDependency, err := resolver.FindDependencyMirror("https://nodejs.org/path-to-skip/dep.tgz", "some-platform-dir")
+					Expect(err).ToNot(HaveOccurred())
+					Expect(bindingResolver.ResolveCall.Receives.Typ).To(Equal("dependency-mirror"))
+					Expect(bindingResolver.ResolveCall.Receives.Provider).To(BeEmpty())
+					Expect(bindingResolver.ResolveCall.Receives.PlatformDir).To(Equal("some-platform-dir"))
+					Expect(boundDependency).To(Equal("https://mirror.example.org/node-dist/dep.tgz"))
+				})
+
+				it("sets mirror excluding a path segment using URL encoding", func() {
+					boundDependency, err := resolver.FindDependencyMirror("https://maven.org/path to skip/dep.tgz", "some-platform-dir")
+					Expect(err).ToNot(HaveOccurred())
+					Expect(bindingResolver.ResolveCall.Receives.Typ).To(Equal("dependency-mirror"))
+					Expect(bindingResolver.ResolveCall.Receives.Provider).To(BeEmpty())
+					Expect(bindingResolver.ResolveCall.Receives.PlatformDir).To(Equal("some-platform-dir"))
+					Expect(boundDependency).To(Equal("https://user:pa$$word,@mirror.example.org/maven/dep.tgz"))
+				})
+			})
+		})
+
 		context("via environment variables", func() {
 			it.Before(func() {
 				Expect(os.Setenv("BP_DEPENDENCY_MIRROR", "https://mirror.example.org/{originalHost}"))
@@ -197,6 +264,43 @@ func testDependencyMirror(t *testing.T, context spec.G, it spec.S) {
 			})
 		})
 
+		context("via environment variables with additional arguments", func() {
+			context("respects skip-path argument", func() {
+				it.Before(func() {
+					Expect(os.Setenv("BP_DEPENDENCY_MIRROR_GITHUB_COM", "mirror=https://mirror.example.org/public-github,skip-path=/path-to-skip"))
+					Expect(os.Setenv("BP_DEPENDENCY_MIRROR_NODEJS_ORG", "https://mirror.example.org/node-dist,skip-path=/path-to-skip"))
+					Expect(os.Setenv("BP_DEPENDENCY_MIRROR_MAVEN_ORG", "https://user%3Apa%24%24word%2C%40mirror.example.org%2Fmaven,skip-path=%2Fpath%20to%20skip"))
+
+					bindingResolver = &fakes.BindingResolver{}
+					resolver = internal.NewDependencyMirrorResolver(bindingResolver)
+				})
+
+				it.After(func() {
+					Expect(os.Unsetenv("BP_DEPENDENCY_MIRROR_GITHUB_COM"))
+					Expect(os.Unsetenv("BP_DEPENDENCY_MIRROR_NODEJS_ORG"))
+					Expect(os.Unsetenv("BP_DEPENDENCY_MIRROR_MAVEN_ORG"))
+				})
+
+				it("sets mirror excluding a path segment with 'mirror' argument", func() {
+					boundDependency, err := resolver.FindDependencyMirror("https://github.com/path-to-skip/dep.tgz", "some-platform-dir")
+					Expect(err).ToNot(HaveOccurred())
+					Expect(boundDependency).To(Equal("https://mirror.example.org/public-github/dep.tgz"))
+				})
+
+				it("sets mirror excluding a path segment without 'mirror' argument", func() {
+					boundDependency, err := resolver.FindDependencyMirror("https://nodejs.org/path-to-skip/dep.tgz", "some-platform-dir")
+					Expect(err).ToNot(HaveOccurred())
+					Expect(boundDependency).To(Equal("https://mirror.example.org/node-dist/dep.tgz"))
+				})
+
+				it("sets mirror excluding a path segment using URL encoding", func() {
+					boundDependency, err := resolver.FindDependencyMirror("https://maven.org/path to skip/dep.tgz", "some-platform-dir")
+					Expect(err).ToNot(HaveOccurred())
+					Expect(boundDependency).To(Equal("https://user:pa$$word,@mirror.example.org/maven/dep.tgz"))
+				})
+			})
+		})
+
 		context("when mirror is provided by both bindings and environment variables", func() {
 			it.Before(func() {
 				tmpDir, err = os.MkdirTemp("", "dependency-mirror")