chore: Add enums for file type

Author: lqiu96

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

@@ -61,9 +61,35 @@ public class GoogleCredentials extends OAuth2Credentials implements QuotaProject
   private static final long serialVersionUID = -1522852442442473691L;
 
   static final String QUOTA_PROJECT_ID_HEADER_KEY = "x-goog-user-project";
-  static final String USER_FILE_TYPE = "authorized_user";
-  static final String SERVICE_ACCOUNT_FILE_TYPE = "service_account";
-  static final String GDCH_SERVICE_ACCOUNT_FILE_TYPE = "gdch_service_account";
+
+  enum GoogleCredentialsType {
+    USER_CREDENTIALS("User Credentials", "authorized_user"),
+    SERVICE_ACCOUNT_CREDENTIALS("Service Account Credentials", "service_account"),
+    GDCH_CREDENTIALS("GDCH Credentials", "gdch_service_account"),
+    EXTERNAL_ACCOUNT_CREDENTIALS("External Account Credentials", "external_account"),
+    EXTERNAL_ACCOUNT_AUTHORIZED_USER_CREDENTIALS("External Account Authorized User Credentials", "external_account_authorized_user"),
+    IMPERSONATED_CREDENTIALS("Impersonated Credentials","impersonated_service_account"),
+    APP_ENGINE_CREDENTIALS("App Engine Credentials", null),
+    CLOUD_SHELL_CREDENTIALS("Cloud Shell Credentials", null),
+    COMPUTE_ENGINE_CREDENTIALS("Compute Engine Credentials", null);
+
+    private final String credentialName;
+    private final String fileType;
+
+    GoogleCredentialsType(String credentialName, String fileType) {
+      this.credentialName = credentialName;
+      this.fileType = fileType;
+    }
+
+    public String getCredentialName() {
+      return credentialName;
+    }
+
+    public String getFileType() {
+      return fileType;
+    }
+  }
+
 
   /* The following package-private fields provide additional info for errors message */
   // Source of the credential (e.g. env var value or well know file location)
@@ -216,36 +242,35 @@ public static GoogleCredentials fromStream(
       throw new IOException("Error reading credentials from stream, 'type' field not specified.");
     }
 
-    if (USER_FILE_TYPE.equals(fileType)) {
+    if (GoogleCredentialsType.USER_CREDENTIALS.getFileType().equals(fileType)) {
       return UserCredentials.fromJson(fileContents, transportFactory);
     }
-    if (SERVICE_ACCOUNT_FILE_TYPE.equals(fileType)) {
+    if (GoogleCredentialsType.SERVICE_ACCOUNT_CREDENTIALS.getFileType().equals(fileType)) {
       return ServiceAccountCredentials.fromJson(fileContents, transportFactory);
     }
-    if (GDCH_SERVICE_ACCOUNT_FILE_TYPE.equals(fileType)) {
+    if (GoogleCredentialsType.GDCH_CREDENTIALS.getFileType().equals(fileType)) {
       return GdchCredentials.fromJson(fileContents);
     }
-    if (ExternalAccountCredentials.EXTERNAL_ACCOUNT_FILE_TYPE.equals(fileType)) {
+    if (GoogleCredentialsType.EXTERNAL_ACCOUNT_CREDENTIALS.getFileType().equals(fileType)) {
       return ExternalAccountCredentials.fromJson(fileContents, transportFactory);
     }
-    if (ExternalAccountAuthorizedUserCredentials.EXTERNAL_ACCOUNT_AUTHORIZED_USER_FILE_TYPE.equals(
-        fileType)) {
+    if (GoogleCredentialsType.EXTERNAL_ACCOUNT_AUTHORIZED_USER_CREDENTIALS.getFileType().equals(fileType)) {
       return ExternalAccountAuthorizedUserCredentials.fromJson(fileContents, transportFactory);
     }
-    if (ImpersonatedCredentials.IMPERSONATED_CREDENTIALS_FILE_TYPE.equals(fileType)) {
+    if (GoogleCredentialsType.IMPERSONATED_CREDENTIALS.getFileType().equals(fileType)) {
       return ImpersonatedCredentials.fromJson(fileContents, transportFactory);
     }
     throw new IOException(
         String.format(
             "Error reading credentials from stream, 'type' value '%s' not recognized."
                 + " Valid values are '%s', '%s', '%s', '%s', '%s', '%s'.",
             fileType,
-            USER_FILE_TYPE,
-            SERVICE_ACCOUNT_FILE_TYPE,
-            GDCH_SERVICE_ACCOUNT_FILE_TYPE,
-            ExternalAccountCredentials.EXTERNAL_ACCOUNT_FILE_TYPE,
-            ExternalAccountAuthorizedUserCredentials.EXTERNAL_ACCOUNT_AUTHORIZED_USER_FILE_TYPE,
-            ImpersonatedCredentials.IMPERSONATED_CREDENTIALS_FILE_TYPE));
+            GoogleCredentialsType.USER_CREDENTIALS.getFileType(),
+            GoogleCredentialsType.SERVICE_ACCOUNT_CREDENTIALS.getFileType(),
+            GoogleCredentialsType.GDCH_CREDENTIALS.getFileType(),
+            GoogleCredentialsType.EXTERNAL_ACCOUNT_CREDENTIALS.getFileType(),
+            GoogleCredentialsType.EXTERNAL_ACCOUNT_AUTHORIZED_USER_CREDENTIALS.getFileType(),
+            GoogleCredentialsType.IMPERSONATED_CREDENTIALS.getFileType()));
   }
 
   /**
@@ -517,10 +542,13 @@ GoogleCredentials withSource(String source) {
   }
 
   /**
-   * Provides additional information regarding credential initialization source - Initialized via
-   * the GOOGLE_APPLICATION_CREDENTIALS env var or well known file type - The type of credential
-   * created principal - Identity used for the credential These fields are populated on a
-   * best-effort basis and may be null or missing
+   * Provides additional information regarding credential initialization source
+   * <ul>
+   *   <li> credential source - Initialized via the GOOGLE_APPLICATION_CREDENTIALS env var or well known file type
+   *   <li> credential type - The type of credential created
+   *   <li> principal - Identity used for the credential
+   * </ul>
+   * These fields are populated on a best-effort basis and may be populated missing
    *
    * @return Map of information regarding how the Credential was initialized
    */
@@ -541,7 +569,7 @@ public Map<String, String> getCredentialInfo() {
   public static class Builder extends OAuth2Credentials.Builder {
     @Nullable protected String quotaProjectId;
     @Nullable protected String universeDomain;
-    String source;
+    @Nullable String source;
 
     protected Builder() {}
 

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

@@ -399,9 +399,9 @@ static ImpersonatedCredentials fromJson(
     }
 
     GoogleCredentials sourceCredentials;
-    if (GoogleCredentials.USER_FILE_TYPE.equals(sourceCredentialsType)) {
+    if (GoogleCredentialsType.USER_CREDENTIALS.getFileType().equals(sourceCredentialsType)) {
       sourceCredentials = UserCredentials.fromJson(sourceCredentialsJson, transportFactory);
-    } else if (GoogleCredentials.SERVICE_ACCOUNT_FILE_TYPE.equals(sourceCredentialsType)) {
+    } else if (GoogleCredentialsType.SERVICE_ACCOUNT_CREDENTIALS.getFileType().equals(sourceCredentialsType)) {
       sourceCredentials =
           ServiceAccountCredentials.fromJson(sourceCredentialsJson, transportFactory);
     } else {

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

@@ -31,7 +31,6 @@
 
 package com.google.auth.oauth2;
 
-import static com.google.auth.oauth2.GoogleCredentials.SERVICE_ACCOUNT_FILE_TYPE;
 import static com.google.auth.oauth2.GoogleCredentials.addQuotaProjectIdToRequestMetadata;
 
 import com.google.api.client.json.GenericJson;
@@ -297,14 +296,14 @@ public static ServiceAccountJwtAccessCredentials fromStream(
     if (fileType == null) {
       throw new IOException("Error reading credentials from stream, 'type' field not specified.");
     }
-    if (SERVICE_ACCOUNT_FILE_TYPE.equals(fileType)) {
+    if (GoogleCredentials.GoogleCredentialsType.SERVICE_ACCOUNT_CREDENTIALS.getFileType().equals(fileType)) {
       return fromJson(fileContents, defaultAudience);
     }
     throw new IOException(
         String.format(
             "Error reading credentials from stream, 'type' value '%s' not recognized."
                 + " Expecting '%s'.",
-            fileType, SERVICE_ACCOUNT_FILE_TYPE));
+            fileType, GoogleCredentials.GoogleCredentialsType.SERVICE_ACCOUNT_CREDENTIALS.getFileType()));
   }
 
   private LoadingCache<JwtClaims, JwtCredentials> createCache() {

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

@@ -177,14 +177,14 @@ public static UserCredentials fromStream(
     if (fileType == null) {
       throw new IOException("Error reading credentials from stream, 'type' field not specified.");
     }
-    if (USER_FILE_TYPE.equals(fileType)) {
+    if (GoogleCredentialsType.USER_CREDENTIALS.getFileType().equals(fileType)) {
       return fromJson(fileContents, transportFactory);
     }
     throw new IOException(
         String.format(
             "Error reading credentials from stream, 'type' value '%s' not recognized."
                 + " Expecting '%s'.",
-            fileType, USER_FILE_TYPE));
+            fileType, GoogleCredentialsType.USER_CREDENTIALS.getFileType()));
   }
 
   /** Refreshes the OAuth2 access token by getting a new access token from the refresh token */
@@ -312,7 +312,7 @@ private GenericData doRefreshAccessToken() throws IOException {
    */
   private InputStream getUserCredentialsStream() throws IOException {
     GenericJson json = new GenericJson();
-    json.put("type", GoogleCredentials.USER_FILE_TYPE);
+    json.put("type", GoogleCredentialsType.USER_CREDENTIALS.getFileType());
     if (refreshToken != null) {
       json.put("refresh_token", refreshToken);
     }

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

@@ -915,7 +915,7 @@ static GenericJson writeGdchServiceAccountJson(
     if (tokenServerUri != null) {
       json.put("token_uri", tokenServerUri.toString());
     }
-    json.put("type", GoogleCredentials.GDCH_SERVICE_ACCOUNT_FILE_TYPE);
+    json.put("type", GoogleCredentials.GoogleCredentialsType.GDCH_CREDENTIALS.getFileType());
     return json;
   }