Enum labels + Transport -> AuthTransport.

Author: rmehta19

oauth2_http/java/com/google/auth/oauth2/ComputeEngineCredentials.java

@@ -109,14 +109,38 @@ public class ComputeEngineCredentials extends GoogleCredentials
   static final int MAX_COMPUTE_PING_TRIES = 3;
   static final int COMPUTE_PING_CONNECTION_TIMEOUT_MS = 500;
 
-  public enum Transport {
-    ALTS,
-    MTLS
+  public enum AuthTransport {
+    // Authenticating to Google APIs via DirectPath
+    ALTS("alts"),
+    // Authenticating to Google APIs via GFE
+    MTLS("mtls");
+
+    private final String label;
+
+    private AuthTransport(String label) {
+      this.label = label;
+    }
+
+    public String getLabel() {
+      return label;
+    }
   }
 
   public enum BindingEnforcement {
-    ON,
-    IAMPOLICY
+    // Binding enforcement will always happen, irrespective of the IAM policy.
+    ON("on"),
+    // Binding enforcement will depend on IAM policy.
+    IAMPOLICY("iam-policy");
+
+    private final String label;
+
+    private BindingEnforcement(String label) {
+      this.label = label;
+    }
+
+    public String getLabel() {
+      return label;
+    }
   }
 
   private static final String METADATA_FLAVOR = "Metadata-Flavor";
@@ -132,7 +156,7 @@ public enum BindingEnforcement {
 
   private final Collection<String> scopes;
 
-  private final Transport transport;
+  private final AuthTransport transport;
   private final BindingEnforcement bindingEnforcement;
 
   private transient HttpTransportFactory transportFactory;
@@ -218,15 +242,11 @@ String createTokenUrlWithScopes() {
     if (!scopes.isEmpty()) {
       tokenUrl.set("scopes", Joiner.on(',').join(scopes));
     }
-    if (transport == Transport.MTLS) {
-      tokenUrl.set("transport", "mtls");
-    } else if (transport == Transport.ALTS) {
-      tokenUrl.set("transport", "alts");
+    if (transport != null) {
+      tokenUrl.set("transport", transport.getLabel());
     }
-    if (bindingEnforcement == BindingEnforcement.ON) {
-      tokenUrl.set("binding-enforcement", "on");
-    } else if (bindingEnforcement == BindingEnforcement.IAMPOLICY) {
-      tokenUrl.set("binding-enforcement", "iam-policy");
+    if (bindingEnforcement != null) {
+      tokenUrl.set("binding-enforcement", bindingEnforcement.getLabel());
     }
     return tokenUrl.toString();
   }
@@ -671,7 +691,7 @@ public static class Builder extends GoogleCredentials.Builder {
     private Collection<String> scopes;
     private Collection<String> defaultScopes;
 
-    private Transport transport;
+    private AuthTransport transport;
     private BindingEnforcement bindingEnforcement;
 
     protected Builder() {
@@ -716,7 +736,7 @@ public Builder setQuotaProjectId(String quotaProjectId) {
     }
 
     @CanIgnoreReturnValue
-    public Builder setTransport(Transport transport) {
+    public Builder setTransport(AuthTransport transport) {
       this.transport = transport;
       return this;
     }
@@ -739,7 +759,7 @@ public Collection<String> getDefaultScopes() {
       return defaultScopes;
     }
 
-    public Transport getTransport() {
+    public AuthTransport getTransport() {
       return transport;
     }
 

oauth2_http/javatests/com/google/auth/oauth2/ComputeEngineCredentialsTest.java

@@ -206,7 +206,7 @@ public void buildTokenUrl_nullTransport() {
   public void buildTokenUrl_nullBindingEnforcement() {
     ComputeEngineCredentials credentials =
         ComputeEngineCredentials.newBuilder()
-            .setTransport(ComputeEngineCredentials.Transport.MTLS)
+            .setTransport(ComputeEngineCredentials.AuthTransport.MTLS)
             .setBindingEnforcement(null)
             .build();
     String softBoundTokenUrl = credentials.createTokenUrlWithScopes();
@@ -218,7 +218,7 @@ public void buildTokenUrl_nullBindingEnforcement() {
   public void buildTokenUrlSoftMtlsBound_mtls_transport() {
     ComputeEngineCredentials credentials =
         ComputeEngineCredentials.newBuilder()
-            .setTransport(ComputeEngineCredentials.Transport.MTLS)
+            .setTransport(ComputeEngineCredentials.AuthTransport.MTLS)
             .build();
     String softBoundTokenUrl = credentials.createTokenUrlWithScopes();
 
@@ -240,7 +240,7 @@ public void buildTokenUrlSoftMtlsBound_iam_enforcement() {
   public void buildTokenUrlSoftMtlsBound_mtls_transport_iam_enforcement() {
     ComputeEngineCredentials credentials =
         ComputeEngineCredentials.newBuilder()
-            .setTransport(ComputeEngineCredentials.Transport.MTLS)
+            .setTransport(ComputeEngineCredentials.AuthTransport.MTLS)
             .setBindingEnforcement(ComputeEngineCredentials.BindingEnforcement.IAMPOLICY)
             .build();
     String softBoundTokenUrl = credentials.createTokenUrlWithScopes();
@@ -263,7 +263,7 @@ public void buildTokenUrlHardMtlsBound_always_enforced() {
   public void buildTokenUrlHardMtlsBound_mtls_transport_always_enforced() {
     ComputeEngineCredentials credentials =
         ComputeEngineCredentials.newBuilder()
-            .setTransport(ComputeEngineCredentials.Transport.MTLS)
+            .setTransport(ComputeEngineCredentials.AuthTransport.MTLS)
             .setBindingEnforcement(ComputeEngineCredentials.BindingEnforcement.ON)
             .build();
     String softBoundTokenUrl = credentials.createTokenUrlWithScopes();
@@ -275,7 +275,7 @@ public void buildTokenUrlHardMtlsBound_mtls_transport_always_enforced() {
   public void buildTokenUrlHardDirectPathBound_alts_transport() {
     ComputeEngineCredentials credentials =
         ComputeEngineCredentials.newBuilder()
-            .setTransport(ComputeEngineCredentials.Transport.ALTS)
+            .setTransport(ComputeEngineCredentials.AuthTransport.ALTS)
             .build();
     String softBoundTokenUrl = credentials.createTokenUrlWithScopes();