Include support for PLUGIN_NO_PUSH as well

* feat: [CI-19349]: Added oidc support for azure connector

* feat: [CI-19349]: Added env variables

* feat: [CI-19349]: Added tests

* Update cmd/drone-acr/main.go

* Update cmd/drone-acr/main.go

* feat: [CI-19349]: Added Debug statements

---------

Co-authored-by: OP (oppenheimer) <21008429+Ompragash@users.noreply.github.com>

card.go

@@ -17,8 +17,14 @@ import (
 	"github.com/inhies/go-bytesize"
 )
 
+// writeCard maintains backward compatibility by using TempTag
 func (p Plugin) writeCard() error {
-	cmd := exec.Command(dockerExe, "inspect", p.Build.TempTag)
+	return p.writeCardForImage(p.Build.TempTag)
+}
+
+// writeCardForImage generates card for any image reference
+func (p Plugin) writeCardForImage(imageRef string) error {
+	cmd := exec.Command(dockerExe, "inspect", imageRef)
 	data, err := cmd.CombinedOutput()
 	if err != nil {
 		return err
@@ -38,7 +44,11 @@ func (p Plugin) writeCard() error {
 	for _, tag := range inspect.RepoTags {
 		sliceTagStruct = append(sliceTagStruct, TagStruct{Tag: tag})
 	}
-	inspect.ParsedRepoTags = sliceTagStruct[1:] // remove the first tag which is always "hash:latest"
+	if len(sliceTagStruct) > 1 {
+		inspect.ParsedRepoTags = sliceTagStruct[1:] // remove the first tag which is always "hash:latest"
+	} else {
+		inspect.ParsedRepoTags = sliceTagStruct
+	}
 	// create the url from repo and registry
 	inspect.URL = mapRegistryToURL(p.Daemon.Registry, p.Build.Repo)
 	cardData, _ := json.Marshal(inspect)

cmd/drone-acr/main.go

@@ -20,6 +20,7 @@ import (
 	"github.com/sirupsen/logrus"
 
 	docker "github.com/drone-plugins/drone-docker"
+	azureutil "github.com/drone-plugins/drone-docker/internal/azure"
 )
 
 type subscriptionUrlResponse struct {
@@ -62,12 +63,14 @@ func main() {
 		password = getenv("SERVICE_PRINCIPAL_CLIENT_SECRET")
 
 		// Service principal credentials
-		clientId       = getenv("CLIENT_ID")
+		clientId       = getenv("CLIENT_ID", "AZURE_CLIENT_ID", "AZURE_APP_ID", "PLUGIN_CLIENT_ID")
-		clientSecret   = getenv("CLIENT_SECRET")
+		clientSecret   = getenv("CLIENT_SECRET", "PLUGIN_CLIENT_SECRET")
-		clientCert     = getenv("CLIENT_CERTIFICATE")
+		clientCert     = getenv("CLIENT_CERTIFICATE", "PLUGIN_CLIENT_CERTIFICATE")
-		tenantId       = getenv("TENANT_ID")
+		tenantId       = getenv("TENANT_ID", "AZURE_TENANT_ID", "PLUGIN_TENANT_ID")
-		subscriptionId = getenv("SUBSCRIPTION_ID")
+		subscriptionId = getenv("SUBSCRIPTION_ID", "PLUGIN_SUBSCRIPTION_ID")
-		publicUrl      = getenv("DAEMON_REGISTRY")
+		publicUrl      = getenv("DAEMON_REGISTRY", "PLUGIN_DAEMON_REGISTRY")
+		authorityHost  = getenv("AZURE_AUTHORITY_HOST", "PLUGIN_AZURE_AUTHORITY_HOST")
+		idToken        = getenv("PLUGIN_OIDC_TOKEN_ID")
 	)
 
 	// default registry value
@@ -80,9 +83,29 @@ func main() {
 		// docker login credentials are not provided
 		var err error
 		username = defaultUsername
-		password, publicUrl, err = getAuth(clientId, clientSecret, clientCert, tenantId, subscriptionId, registry)
+		if idToken != "" && clientId != "" && tenantId != "" {
-		if err != nil {
+			logrus.Debug("Using OIDC authentication flow")
-			logrus.Fatal(err)
+			var aadToken string
+			aadToken, err = azureutil.GetAADAccessTokenViaClientAssertion(context.Background(), tenantId, clientId, idToken, authorityHost)
+			if err != nil {
+				logrus.Fatal(err)
+			}
+			var p string
+			p, err = getPublicUrl(aadToken, registry, subscriptionId)
+			if err == nil {
+				publicUrl = p
+			} else {
+				fmt.Fprintf(os.Stderr, "failed to get public url with error: %s\n", err)
+			}
+			password, err = fetchACRToken(tenantId, aadToken, registry)
+			if err != nil {
+				logrus.Fatal(err)
+			}
+		} else {
+			password, publicUrl, err = getAuth(clientId, clientSecret, clientCert, tenantId, subscriptionId, registry)
+			if err != nil {
+				logrus.Fatal(err)
+			}
 		}
 	}
 

cmd/drone-acr/main_test.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+    "os"
+    "testing"
+)
+
+func TestGetAuthInputValidation(t *testing.T) {
+    // missing tenant
+    if _, _, err := getAuth("client", "secret", "", "", "sub", "registry.azurecr.io"); err == nil {
+        t.Fatalf("expected error for missing tenantId")
+    }
+    // missing clientId
+    if _, _, err := getAuth("", "secret", "", "tenant", "sub", "registry.azurecr.io"); err == nil {
+        t.Fatalf("expected error for missing clientId")
+    }
+    // missing both secret and cert
+    if _, _, err := getAuth("client", "", "", "tenant", "sub", "registry.azurecr.io"); err == nil {
+        t.Fatalf("expected error for missing credentials")
+    }
+}
+
+func TestGetenvAuthorityHost(t *testing.T) {
+    os.Setenv("AZURE_AUTHORITY_HOST", "https://login.microsoftonline.us")
+    defer os.Unsetenv("AZURE_AUTHORITY_HOST")
+
+    got := getenv("AZURE_AUTHORITY_HOST")
+    if got != "https://login.microsoftonline.us" {
+        t.Fatalf("expected AZURE_AUTHORITY_HOST to be returned, got %q", got)
+    }
+}
+

cmd/drone-docker/main.go

@@ -33,7 +33,7 @@ func main() {
 		cli.BoolFlag{
 			Name:   "dry-run",
 			Usage:  "dry run disables docker push",
-			EnvVar: "PLUGIN_DRY_RUN",
+			EnvVar: "PLUGIN_DRY_RUN, PLUGIN_NO_PUSH",
 		},
 		cli.StringFlag{
 			Name:   "remote.url",
@@ -339,6 +339,16 @@ func main() {
 			Usage:  "additional cosign parameters (e.g., annotations, flags)",
 			EnvVar: "PLUGIN_COSIGN_PARAMS",
 		},
+		cli.BoolFlag{
+			Name:   "push-only",
+			Usage:  "skip build and only push images",
+			EnvVar: "PLUGIN_PUSH_ONLY",
+		},
+		cli.StringFlag{
+			Name:   "source-image",
+			Usage:  "source image to tag and push (format: repo:tag)",
+			EnvVar: "PLUGIN_SOURCE_IMAGE",
+		},
 	}
 
 	if err := app.Run(os.Args); err != nil {
@@ -419,6 +429,8 @@ func run(c *cli.Context) error {
 			Password:   c.String("cosign.password"),
 			Params:     c.String("cosign.params"),
 		},
+		PushOnly:    c.Bool("push-only"),
+		SourceImage: c.String("source-image"),
 	}
 
 	if c.Bool("tags.auto") {

docker.go

@@ -96,6 +96,8 @@ type (
 		BaseImageRegistry string       // Docker registry to pull base image
 		BaseImageUsername string       // Docker registry username to pull base image
 		BaseImagePassword string       // Docker registry password to pull base image
+		PushOnly          bool         // Push only mode, skips build process
+		SourceImage       string       // Source image to push (optional)
 	}
 
 	Card []struct {
@@ -201,7 +203,8 @@ func (p Plugin) Exec() error {
 			fmt.Println(out)
 			return fmt.Errorf("Error authenticating base connector: exit status 1")
 		}
-	} else {
+	} else if !p.PushOnly {
+		// Skip base image connector warning in push-only mode (not pulling anything)
 		fmt.Println("\033[33mTo ensure consistent and reliable pipeline execution, we recommend setting up a Base Image Connector.\033[0m\n" +
 			"\033[33mWhile optional at this time, configuring it helps prevent failures caused by Docker Hub's rate limits.\033[0m")
 	}
@@ -229,6 +232,16 @@ func (p Plugin) Exec() error {
 		}
 	}
 
+	// Enforce mutual exclusivity: push-only and dry-run cannot be used together
+	if p.PushOnly && p.Dryrun {
+		return fmt.Errorf("conflict: push-only and dry-run cannot be used together")
+	}
+
+	// Handle push-only mode if requested
+	if p.PushOnly {
+		return p.pushOnly()
+	}
+
 	if p.Build.Squash && !p.Daemon.Experimental {
 		fmt.Println("Squash build flag is only available when Docker deamon is started with experimental flag. Ignoring...")
 		p.Build.Squash = false
@@ -742,6 +755,22 @@ func getDigest(buildName string) (string, error) {
 	return "", errors.New("unable to fetch digest")
 }
 
+// imageExists checks if an image exists in local daemon
+func imageExists(tag string) bool {
+	cmd := exec.Command(dockerExe, "image", "inspect", tag)
+	return cmd.Run() == nil
+}
+
+// getDigestAfterPush gets digest from a pushed image
+func getDigestAfterPush(tag string) (string, error) {
+	cmd := exec.Command(dockerExe, "inspect", "--format", "{{ index (split (index .RepoDigests 0) \"@\") 1 }}", tag)
+	output, err := cmd.Output()
+	if err != nil {
+		return "", fmt.Errorf("failed to get digest for %s: %w", tag, err)
+	}
+	return strings.TrimSpace(string(output)), nil
+}
+
 // shouldSignWithCosign determines if cosign signing should be performed
 func (p Plugin) shouldSignWithCosign() bool {
 	return p.Cosign.PrivateKey != ""
@@ -837,7 +866,7 @@ func executeCosignCommand(cmd *exec.Cmd) {
 	cmd.Stdout = os.Stdout
 	cmd.Stderr = os.Stderr
 	fmt.Printf("🚀 Executing: %s %s\n", cmd.Path, strings.Join(cmd.Args[1:], " "))
-	
+
 	if err := cmd.Run(); err != nil {
 		fmt.Printf("⚠️  WARNING: Image signing failed: %s\n", err)
 		fmt.Printf("   Image was pushed successfully but could not be signed\n")
@@ -845,4 +874,164 @@ func executeCosignCommand(cmd *exec.Cmd) {
 	}
 }
 
+// pushOnly handles pushing images without building them
+func (p Plugin) pushOnly() error {
+	// Check if source image is specified
+	sourceImageName := p.SourceImage
+	var sourceTags []string
 
+	if sourceImageName == "" {
+		// If no source image specified, use the repo and first tag
+		fmt.Println("source_image not provided, using repo and tag value")
+		sourceImageName = p.Build.Repo
+		sourceTags = p.Build.Tags
+	} else {
+		// If source image is specified, check if it has a tag
+		lastColonIndex := strings.LastIndex(sourceImageName, ":")
+		if lastColonIndex > 0 && lastColonIndex < len(sourceImageName) {
+			// Check if there's a slash after the last colon (indicating it's a port, not a tag)
+			// For example: registry:5000/image (has slash after colon - port not tag)
+			// vs image:tag (no slash after colon - it's a tag)
+			if strings.LastIndex(sourceImageName, "/") > lastColonIndex {
+				// The last colon is part of the registry:port, not a tag separator
+				sourceTags = []string{"latest"}
+			} else {
+				// The last colon separates the tag
+				tag := sourceImageName[lastColonIndex+1:]
+				sourceImageName = sourceImageName[:lastColonIndex]
+
+				if tag == "" {
+					fmt.Printf("No tag specified in source image (or empty tag). Using 'latest' as the default tag.\n")
+					tag = "latest"
+				}
+				sourceTags = []string{tag}
+			}
+		} else {
+			// Default to "latest" if no tag specified
+			sourceTags = []string{"latest"}
+		}
+		fmt.Printf("Using source image: %s with tag(s): %s\n", sourceImageName, strings.Join(sourceTags, ", "))
+	}
+
+	// For each source tag and target tag combination
+	var digest string
+	var firstPushedImage string
+
+	for _, sourceTag := range sourceTags {
+		sourceFullImageName := fmt.Sprintf("%s:%s", sourceImageName, sourceTag)
+
+		// Check if the source image exists in local daemon
+		if !imageExists(sourceFullImageName) {
+			fmt.Printf("Warning: Source image %s not found\n", sourceFullImageName)
+			// Continue to the next source tag if available, otherwise return error
+			if len(sourceTags) > 1 {
+				continue
+			}
+			return fmt.Errorf("source image %s not found, cannot push", sourceFullImageName)
+		}
+
+		// For each target tag, tag and push
+		for _, targetTag := range p.Build.Tags {
+			targetFullImageName := fmt.Sprintf("%s:%s", p.Build.Repo, targetTag)
+
+			// Skip if source and target are identical
+			if sourceFullImageName == targetFullImageName {
+				fmt.Printf("Source and target image names are identical: %s\n", sourceFullImageName)
+			} else {
+				// Tag the source image with the target name
+				fmt.Printf("Tagging %s as %s\n", sourceFullImageName, targetFullImageName)
+				tagCmd := exec.Command(dockerExe, "tag", sourceFullImageName, targetFullImageName)
+				tagCmd.Stdout = os.Stdout
+				tagCmd.Stderr = os.Stderr
+				trace(tagCmd)
+				if err := tagCmd.Run(); err != nil {
+					return fmt.Errorf("failed to tag image %s as %s: %w", sourceFullImageName, targetFullImageName, err)
+				}
+			}
+		}
+	}
+
+	// Push all target images
+	for _, tag := range p.Build.Tags {
+		fullImageName := fmt.Sprintf("%s:%s", p.Build.Repo, tag)
+
+		// Check if image exists in local daemon
+		if !imageExists(fullImageName) {
+			return fmt.Errorf("image %s not found, cannot push", fullImageName)
+		}
+
+		// Push image
+		fmt.Println("Pushing image:", fullImageName)
+		pushCmd := commandPush(p.Build, tag)
+		pushCmd.Stdout = os.Stdout
+		pushCmd.Stderr = os.Stderr
+		trace(pushCmd)
+		if err := pushCmd.Run(); err != nil {
+			return fmt.Errorf("failed to push image %s: %w", fullImageName, err)
+		}
+
+		// Track the first pushed image for card generation
+		if firstPushedImage == "" {
+			firstPushedImage = fullImageName
+		}
+
+		// Get the digest after push (we only need one)
+		if digest == "" {
+			d, err := getDigestAfterPush(fullImageName)
+			if err == nil {
+				digest = d
+			} else {
+				fmt.Printf("Warning: Could not get digest for %s: %v\n", fullImageName, err)
+			}
+		}
+	}
+
+	// Output the adaptive card
+	if firstPushedImage != "" {
+		if err := p.writeCardForImage(firstPushedImage); err != nil {
+			fmt.Printf("Could not create adaptive card. %s\n", err)
+		}
+	}
+
+	// Write to artifact file
+	if p.ArtifactFile != "" && digest != "" {
+		if err := drone.WritePluginArtifactFile(
+			p.Daemon.RegistryType,
+			p.ArtifactFile,
+			p.Daemon.Registry,
+			p.Build.Repo,
+			digest,
+			p.Build.Tags,
+		); err != nil {
+			fmt.Printf("Failed to write plugin artifact file at path: %s with error: %s\n",
+				p.ArtifactFile, err)
+		}
+	}
+
+	// Handle cosign signing after push
+	if p.shouldSignWithCosign() {
+		// Set up environment variables for cosign
+		os.Setenv("COSIGN_YES", "true")
+
+		if digest != "" {
+			fmt.Printf("🔐 Found image digest: %s\n", digest)
+
+			// Sign with digest reference
+			imageRef := fmt.Sprintf("%s@%s", p.Build.Repo, digest)
+			cosignCmd := createCosignCommand(imageRef, p.Cosign)
+			executeCosignCommand(cosignCmd)
+		} else {
+			fmt.Printf("⚠️  WARNING: Could not get image digest for cosign signing\n")
+			fmt.Printf("   Falling back to tag-based signing\n")
+
+			// Fall back to tag-based signing for each tag
+			for _, tag := range p.Build.Tags {
+				imageRef := fmt.Sprintf("%s:%s", p.Build.Repo, tag)
+				cosignCmd := createCosignCommand(imageRef, p.Cosign)
+				executeCosignCommand(cosignCmd)
+			}
+		}
+	}
+
+	return nil
+}

go.mod

@@ -14,13 +14,12 @@ require (
 	github.com/sirupsen/logrus v1.9.0
 	github.com/stretchr/testify v1.10.0
 	github.com/urfave/cli v1.22.2
-	golang.org/x/oauth2 v0.13.0
+	golang.org/x/oauth2 v0.27.0
 	google.golang.org/api v0.146.0
 )
 
 require (
-	cloud.google.com/go/compute v1.23.1 // indirect
+	cloud.google.com/go/compute/metadata v0.3.0 // indirect
-	cloud.google.com/go/compute/metadata v0.2.3 // indirect
 	github.com/Azure/azure-sdk-for-go/sdk/internal v1.10.0 // indirect
 	github.com/AzureAD/microsoft-authentication-library-for-go v1.3.3 // indirect
 	github.com/cpuguy83/go-md2man/v2 v2.0.2 // indirect
@@ -42,7 +41,6 @@ require (
 	golang.org/x/net v0.37.0 // indirect
 	golang.org/x/sys v0.31.0 // indirect
 	golang.org/x/text v0.23.0 // indirect
-	google.golang.org/appengine v1.6.8 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20231016165738-49dd2c1f3d0b // indirect
 	google.golang.org/grpc v1.59.0 // indirect
 	google.golang.org/protobuf v1.31.0 // indirect

go.sum

@@ -1,8 +1,6 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
-cloud.google.com/go/compute v1.23.1 h1:V97tBoDaZHb6leicZ1G6DLK2BAaZLJ/7+9BB/En3hR0=
+cloud.google.com/go/compute/metadata v0.3.0 h1:Tz+eQXMEqDIKRsmY3cHTL6FVaynIjX2QxYC4trgAKZc=
-cloud.google.com/go/compute v1.23.1/go.mod h1:CqB3xpmPKKt3OJpW2ndFIXnA9A4xAy/F3Xp1ixncW78=
+cloud.google.com/go/compute/metadata v0.3.0/go.mod h1:zFmK7XCadkQkj6TtorcaGlCW1hT1fIilQDwofLpJ20k=
-cloud.google.com/go/compute/metadata v0.2.3 h1:mg4jlk7mCAj6xXp9UJ4fjI9VUI5rubuGBW5aJ7UnBMY=
-cloud.google.com/go/compute/metadata v0.2.3/go.mod h1:VAV5nSsACxMJvgaAuX6Pk2AawlZn8kiOGuCv6gTkwuA=
 github.com/99designs/httpsignatures-go v0.0.0-20170731043157-88528bf4ca7e/go.mod h1:Xa6lInWHNQnuWoF0YPSsx+INFA9qk7/7pTjwb3PInkY=
 github.com/Azure/azure-sdk-for-go/sdk/azcore v1.17.1 h1:DSDNVxqkoXJiko6x8a90zidoYqnYYa6c1MTzDKzKkTo=
 github.com/Azure/azure-sdk-for-go/sdk/azcore v1.17.1/go.mod h1:zGqV2R4Cr/k8Uye5w+dgQ06WJtEcbQG/8J7BB6hnCr4=
@@ -61,7 +59,6 @@ github.com/golang/protobuf v1.4.0/go.mod h1:jodUvKwWbYaEsadDk5Fwe5c77LiNKVO9IDvq
 github.com/golang/protobuf v1.4.1/go.mod h1:U8fpvMrcmy5pZrNK1lt4xCsGvpyWQ/VVv6QDs8UjoX8=
 github.com/golang/protobuf v1.4.3/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw735rRwI=
 github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
-github.com/golang/protobuf v1.5.2/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
 github.com/golang/protobuf v1.5.3 h1:KhyjKVUg7Usr/dYsdSqoFveMYd5ko72D+zANwlG1mmg=
 github.com/golang/protobuf v1.5.3/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
 github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
@@ -124,57 +121,42 @@ github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOf
 github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 github.com/urfave/cli v1.22.2 h1:gsqYFH8bb9ekPA12kRo0hfjngWQjkJPlN9R0N78BoUo=
 github.com/urfave/cli v1.22.2/go.mod h1:Gos4lmkARVdJ6EkW0WaNv/tZAAMe9V7XWyB60NtXRu0=
-github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
 go.opencensus.io v0.24.0 h1:y73uSU6J157QMP2kn2r30vwW1A2W2WFwSCGnAVxeaD0=
 go.opencensus.io v0.24.0/go.mod h1:vNK8G9p7aAivkbmorf4v+7Hgx+Zs0yY+0fOtgBfjQKo=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
-golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
 golang.org/x/crypto v0.36.0 h1:AnAEvhDddvBdpY+uR+MyHmuZzzNqXSe/GvuDeob5L34=
 golang.org/x/crypto v0.36.0/go.mod h1:Y4J0ReaxCR1IMaabaSMugxJES1EpwhBHhv2bDHklZvc=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
 golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvxsM5YxQ5yQlVC4a0KAMCusXpPoU=
 golang.org/x/lint v0.0.0-20190313153728-d0100b6bd8b3/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
-golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91VN4djpZkiMVwK6gcyfeH4XE8wZrZaV4=
 golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20180826012351-8a410e7b638d/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190213061140-3a22650c66bd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20201110031124-69a78807bb2b/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
-golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
-golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
 golang.org/x/net v0.37.0 h1:1zLorHbz+LYj7MQlSf1+2tPIIgibq2eL5xkrGk6f+2c=
 golang.org/x/net v0.37.0/go.mod h1:ivrbrMbzFq5J41QOQh0siUuly180yBYtLp+CKbEaFx8=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
-golang.org/x/oauth2 v0.13.0 h1:jDDenyj+WgFtmV3zYVoi8aE2BwtXFLWOA67ZfNWftiY=
+golang.org/x/oauth2 v0.27.0 h1:da9Vo7/tDv5RH/7nZDz1eMGS/q1Vv1N/7FCrBhI9I3M=
-golang.org/x/oauth2 v0.13.0/go.mod h1:/JMhi4ZRXAf4HG9LiNmxvk+45+96RUlVThiH8FzNBn0=
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 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20181108010431-42b317875d0f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
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 golang.org/x/sys v0.0.0-20180830151530-49385e6e1522/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220715151400-c0bba94af5f8/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.1.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.31.0 h1:ioabZlmFYtWhL+TRYpcnNlLwhyxaM9kWTDEmfnprqik=
 golang.org/x/sys v0.31.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
-golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
-golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
-golang.org/x/text v0.3.7/go.mod h1:u+2+/6zg+i71rQMx5EYifcz6MCKuco9NR6JIITiCfzQ=
-golang.org/x/text v0.3.8/go.mod h1:E6s5w1FMmriuDzIBO73fBruAKo1PCIq6d2Q6DHfQ8WQ=
 golang.org/x/text v0.23.0 h1:D71I7dUrlY+VX0gQShAThNGHFxZ13dGLBHQLVl1mJlY=
 golang.org/x/text v0.23.0/go.mod h1:/BLNzu4aZCJ1+kcD0DNRotWKage4q2rGVAg4o22unh4=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
@@ -182,16 +164,11 @@ golang.org/x/tools v0.0.0-20190114222345-bf090417da8b/go.mod h1:n7NCudcB/nEzxVGm
 golang.org/x/tools v0.0.0-20190226205152-f727befe758c/go.mod h1:9Yl7xja0Znq3iFh3HoIrodX9oNMXvdceNzlUR8zjMvY=
 golang.org/x/tools v0.0.0-20190311212946-11955173bddd/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
 golang.org/x/tools v0.0.0-20190524140312-2c0ae7006135/go.mod h1:RgjU9mgBXZiqYHBnxXauZ1Gv1EHHAz9KjViQ78xBX0Q=
-golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
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 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/api v0.146.0 h1:9aBYT4vQXt9dhCuLNfwfd3zpwu8atg0yPkjBymwSrOM=
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 google.golang.org/appengine v1.1.0/go.mod h1:EbEs0AVv82hx2wNQdGPgUI5lhzA/G0D9YwlJXL52JkM=
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 google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
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internal/azure/tokenutil.go

@@ -0,0 +1,75 @@
+package azure
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+)
+
+const DefaultResource = "https://management.azure.com/"
+const defaultAuthorityHost = "https://login.microsoftonline.com"
+const defaultHTTPTimeout = 30 * time.Second
+
+// GetAADAccessTokenViaClientAssertion exchanges an external OIDC ID token for an Azure AD access token
+
+func GetAADAccessTokenViaClientAssertion(ctx context.Context, tenantID, clientID, oidcToken, authorityHost string) (string, error) {
+    resource := DefaultResource
+
+	form := url.Values{
+		"client_id":             {clientID},
+		"scope":                 {resource + ".default"},
+		"grant_type":            {"client_credentials"},
+		"client_assertion_type": {"urn:ietf:params:oauth:client-assertion-type:jwt-bearer"},
+		"client_assertion":      {oidcToken},
+	}
+
+	base := authorityHost
+	if strings.TrimSpace(base) == "" {
+		base = defaultAuthorityHost
+	}
+	base = strings.TrimRight(base, "/")
+	endpoint := fmt.Sprintf("%s/%s/oauth2/v2.0/token", base, tenantID)
+
+	client := &http.Client{Timeout: defaultHTTPTimeout}
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, endpoint, strings.NewReader(form.Encode()))
+	if err != nil {
+		return "", err
+	}
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	req.Header.Set("Accept", "application/json")
+
+	resp, err := client.Do(req)
+	if err != nil {
+		return "", err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
+		var aadErr struct {
+			Error            string `json:"error"`
+			ErrorDescription string `json:"error_description"`
+		}
+		limited := io.LimitedReader{R: resp.Body, N: 4096}
+		_ = json.NewDecoder(&limited).Decode(&aadErr)
+		if aadErr.Error != "" {
+			return "", fmt.Errorf("AAD token request failed: status=%d, error=%s", resp.StatusCode, aadErr.Error)
+		}
+		return "", fmt.Errorf("AAD token request failed: status=%d", resp.StatusCode)
+	}
+	var payload struct {
+		AccessToken string `json:"access_token"`
+		TokenType   string `json:"token_type"`
+		ExpiresIn   int    `json:"expires_in"`
+	}
+	if err := json.NewDecoder(resp.Body).Decode(&payload); err != nil {
+		return "", err
+	}
+	if payload.AccessToken == "" {
+		return "", fmt.Errorf("AAD token response missing access_token")
+	}
+	return payload.AccessToken, nil
+}

internal/azure/tokenutil_test.go

@@ -0,0 +1,104 @@
+package azure
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+)
+
+func TestGetAADAccessTokenViaClientAssertion_Success(t *testing.T) {
+
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPost {
+			t.Fatalf("expected POST, got %s", r.Method)
+		}
+		if ct := r.Header.Get("Content-Type"); !strings.Contains(ct, "application/x-www-form-urlencoded") {
+			t.Fatalf("expected form content-type, got %s", ct)
+		}
+		if err := r.ParseForm(); err != nil {
+			t.Fatalf("failed parsing form: %v", err)
+		}
+		assertEq(t, r.Form.Get("client_id"), "client")
+		assertEq(t, r.Form.Get("grant_type"), "client_credentials")
+		assertEq(t, r.Form.Get("client_assertion_type"), "urn:ietf:params:oauth:client-assertion-type:jwt-bearer")
+		assertEq(t, r.Form.Get("client_assertion"), "idtoken")
+		assertEq(t, r.Form.Get("scope"), DefaultResource+".default")
+
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte(`{"access_token":"AT","token_type":"Bearer","expires_in":3600}`))
+	}))
+	defer ts.Close()
+
+	tok, err := GetAADAccessTokenViaClientAssertion(context.Background(), "tenant", "client", "idtoken", ts.URL)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if tok != "AT" {
+		t.Fatalf("expected access token AT, got %q", tok)
+	}
+}
+
+func TestGetAADAccessTokenViaClientAssertion_400WithErrorField(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusBadRequest)
+		_, _ = w.Write([]byte(`{"error":"invalid_client","error_description":"bad"}`))
+	}))
+	defer ts.Close()
+
+	_, err := GetAADAccessTokenViaClientAssertion(context.Background(), "tenant", "client", "idtoken", ts.URL)
+	if err == nil || !strings.Contains(err.Error(), "status=400") || !strings.Contains(err.Error(), "invalid_client") {
+		t.Fatalf("expected 400 with invalid_client error, got %v", err)
+	}
+}
+
+func TestGetAADAccessTokenViaClientAssertion_400WithoutErrorField(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusBadRequest)
+		_, _ = w.Write([]byte("{}"))
+	}))
+	defer ts.Close()
+
+	_, err := GetAADAccessTokenViaClientAssertion(context.Background(), "tenant", "client", "idtoken", ts.URL)
+	if err == nil || !strings.Contains(err.Error(), "status=400") {
+		t.Fatalf("expected 400 error, got %v", err)
+	}
+}
+
+func TestGetAADAccessTokenViaClientAssertion_MalformedJSON(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte("not-json"))
+	}))
+	defer ts.Close()
+
+	_, err := GetAADAccessTokenViaClientAssertion(context.Background(), "tenant", "client", "idtoken", ts.URL)
+	if err == nil {
+		t.Fatalf("expected JSON decode error, got nil")
+	}
+}
+
+func TestGetAADAccessTokenViaClientAssertion_MissingAccessToken(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		w.WriteHeader(http.StatusOK)
+		_, _ = w.Write([]byte(`{"token_type":"Bearer","expires_in":3600}`))
+	}))
+	defer ts.Close()
+
+	_, err := GetAADAccessTokenViaClientAssertion(context.Background(), "tenant", "client", "idtoken", ts.URL)
+	if err == nil || !strings.Contains(err.Error(), "missing access_token") {
+		t.Fatalf("expected missing access_token error, got %v", err)
+	}
+}
+
+func assertEq(t *testing.T, got, want string) {
+	t.Helper()
+	if got != want {
+		t.Fatalf("mismatch: got=%q want=%q", got, want)
+	}
+}
+