Added GetModel functionality and tests

src/index.d.ts

@@ -5252,11 +5252,11 @@ declare namespace admin.machineLearning {
     readonly validationError?: string;
     readonly published: boolean;
     readonly etag: string;
-    readonly modelHash: string;
+    readonly modelHash?: string;
     readonly locked: boolean;
     waitForUnlocked(maxTimeSeconds?: number): Promise<void>;
 
-    readonly tfLiteModel?: TFLiteModel;
+    readonly tfliteModel?: TFLiteModel;
   }
 
   /**

src/machine-learning/machine-learning-api-client.ts

@@ -0,0 +1,194 @@
+/*!
+ * Copyright 2020 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { HttpRequestConfig, HttpClient, HttpError, AuthorizedHttpClient } from '../utils/api-request';
+import { PrefixedFirebaseError } from '../utils/error';
+import { FirebaseMachineLearningError, MachineLearningErrorCode } from './machine-learning-utils';
+import * as utils from '../utils/index';
+import * as validator from '../utils/validator';
+import { FirebaseApp } from '../firebase-app';
+
+const ML_V1BETA1_API = 'https://mlkit.googleapis.com/v1beta1';
+const FIREBASE_VERSION_HEADER = {
+  'X-Firebase-Client': 'fire-admin-node/<XXX_SDK_VERSION_XXX>',
+};
+
+export interface StatusErrorResponse {
+    readonly code: number;
+    readonly message: string;
+}
+
+export interface ModelContent {
+  readonly displayName?: string;
+  readonly tags?: string[];
+  readonly state?: {
+    readonly validationError?: StatusErrorResponse;
+    readonly published?: boolean;
+  };
+  readonly tfliteModel?: {
+    readonly gcsTfliteUri: string;
+    readonly sizeBytes: number;
+  };
+}
+
+export interface ModelResponse extends ModelContent {
+  readonly name: string;
+  readonly createTime: string;
+  readonly updateTime: string;
+  readonly etag: string;
+  readonly modelHash?: string;
+}
+
+
+/**
+ * Class that facilitates sending requests to the Firebase ML backend API.
+ *
+ * @private
+ */
+export class MachineLearningApiClient {
+  private readonly httpClient: HttpClient;
+  private projectIdPrefix?: string;
+
+  constructor(private readonly app: FirebaseApp) {
+    if (!validator.isNonNullObject(app) || !('options' in app)) {
+      throw new FirebaseMachineLearningError(
+        'invalid-argument',
+        'First argument passed to admin.machineLearning() must be a valid '
+          + 'Firebase app instance.');
+    }
+
+    this.httpClient = new AuthorizedHttpClient(app);
+  }
+
+  public getModel(modelId: string): Promise<ModelResponse> {
+    return Promise.resolve()
+      .then(() => {
+        return this.getModelName(modelId);
+      })
+      .then((modelName) => {
+        return this.getResource<ModelResponse>(modelName);
+      });
+  }
+
+  /**
+   * Gets the specified resource from the ML API. Resource names must be the short names without project
+   * ID prefix (e.g. `models/123456789`).
+   *
+   * @param {string} name Full qualified name of the resource to get.
+   * @returns {Promise<T>} A promise that fulfills with the resource.
+   */
+  private getResource<T>(name: string): Promise<T> {
+    return this.getUrl()
+      .then((url) => {
+        const request: HttpRequestConfig = {
+          method: 'GET',
+          url: `${url}/${name}`,
+        };
+        return this.sendRequest<T>(request);
+      });
+  }
+
+  private sendRequest<T>(request: HttpRequestConfig): Promise<T> {
+    request.headers = FIREBASE_VERSION_HEADER;
+    return this.httpClient.send(request)
+      .then((resp) => {
+        return resp.data as T;
+      })
+      .catch((err) => {
+        throw this.toFirebaseError(err);
+      });
+  }
+
+  private toFirebaseError(err: HttpError): PrefixedFirebaseError {
+    if (err instanceof PrefixedFirebaseError) {
+      return err;
+    }
+
+    const response = err.response;
+    if (!response.isJson()) {
+      return new FirebaseMachineLearningError(
+        'unknown-error',
+        `Unexpected response with status: ${response.status} and body: ${response.text}`);
+    }
+
+    const error: Error = (response.data as ErrorResponse).error || {};
+    let code: MachineLearningErrorCode = 'unknown-error';
+    if (error.status && error.status in ERROR_CODE_MAPPING) {
+      code = ERROR_CODE_MAPPING[error.status];
+    }
+    const message = error.message || `Unknown server error: ${response.text}`;
+    return new FirebaseMachineLearningError(code, message);
+  }
+
+  private getUrl(): Promise<string> {
+    return this.getProjectIdPrefix()
+      .then((projectIdPrefix) => {
+        return `${ML_V1BETA1_API}/${this.projectIdPrefix}`;
+      });
+  }
+
+  private getProjectIdPrefix(): Promise<string> {
+    if (this.projectIdPrefix) {
+      return Promise.resolve(this.projectIdPrefix);
+    }
+
+    return utils.findProjectId(this.app)
+      .then((projectId) => {
+        if (!validator.isNonEmptyString(projectId)) {
+          throw new FirebaseMachineLearningError(
+            'invalid-argument',
+            'Failed to determine project ID. Initialize the SDK with service account credentials, or '
+            + 'set project ID as an app option. Alternatively, set the GOOGLE_CLOUD_PROJECT '
+            + 'environment variable.');
+        }
+
+        this.projectIdPrefix = `projects/${projectId}`;
+        return this.projectIdPrefix;
+      });
+  }
+
+  private getModelName(modelId: string): string {
+    if (!validator.isNonEmptyString(modelId)) {
+      throw new FirebaseMachineLearningError(
+        'invalid-argument', 'Model ID must be a non-empty string.');
+    }
+
+    if (modelId.indexOf('/') !== -1) {
+      throw new FirebaseMachineLearningError(
+        'invalid-argument', 'Model ID must not contain any "/" characters.');
+    }
+
+    return `models/${modelId}`;
+  }
+}
+
+interface ErrorResponse {
+  error?: Error;
+}
+
+interface Error {
+  code?: number;
+  message?: string;
+  status?: string;
+}
+
+const ERROR_CODE_MAPPING: {[key: string]: MachineLearningErrorCode} = {
+  INVALID_ARGUMENT: 'invalid-argument',
+  NOT_FOUND: 'not-found',
+  RESOURCE_EXHAUSTED: 'resource-exhausted',
+  UNAUTHENTICATED: 'authentication-error',
+  UNKNOWN: 'unknown-error',
+};

src/machine-learning/machine-learning-utils.ts

@@ -0,0 +1,34 @@
+/*!
+ * Copyright 2020 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { PrefixedFirebaseError } from '../utils/error';
+
+export type MachineLearningErrorCode =
+  'already-exists'
+  | 'authentication-error'
+  | 'internal-error'
+  | 'invalid-argument'
+  | 'invalid-server-response'
+  | 'not-found'
+  | 'resource-exhausted'
+  | 'service-unavailable'
+  | 'unknown-error';
+
+export class FirebaseMachineLearningError extends PrefixedFirebaseError {
+  constructor(code: MachineLearningErrorCode, message: string) {
+    super('machine-learning', code, message);
+  }
+}

src/machine-learning/machine-learning.ts

@@ -17,9 +17,11 @@
 
 import {FirebaseApp} from '../firebase-app';
 import {FirebaseServiceInterface, FirebaseServiceInternalsInterface} from '../firebase-service';
+import {MachineLearningApiClient, ModelResponse} from './machine-learning-api-client';
 import {FirebaseError} from '../utils/error';
 
 import * as validator from '../utils/validator';
+import {FirebaseMachineLearningError} from './machine-learning-utils';
 
 // const ML_HOST = 'mlkit.googleapis.com';
 
@@ -58,6 +60,7 @@ export interface ListModelsResult {
 export class MachineLearning implements FirebaseServiceInterface {
   public readonly INTERNAL = new MachineLearningInternals();
 
+  private readonly client: MachineLearningApiClient;
   private readonly appInternal: FirebaseApp;
 
   /**
@@ -68,12 +71,13 @@ export class MachineLearning implements FirebaseServiceInterface {
     if (!validator.isNonNullObject(app) || !('options' in app)) {
       throw new FirebaseError({
         code: 'machine-learning/invalid-argument',
-        message: 'First argument passed to admin.MachineLearning() must be a ' +
+        message: 'First argument passed to admin.machineLearning() must be a ' +
             'valid Firebase app instance.',
       });
     }
 
     this.appInternal = app;
+    this.client = new MachineLearningApiClient(app);
   }
 
   /**
@@ -138,7 +142,10 @@ export class MachineLearning implements FirebaseServiceInterface {
    * @return {Promise<Model>} A Promise fulfilled with the unpublished model.
    */
   public getModel(modelId: string): Promise<Model> {
-    throw new Error('NotImplemented');
+    return this.client.getModel(modelId)
+      .then((modelResponse) => {
+         return new Model(modelResponse);
+      });
   }
 
   /**
@@ -172,14 +179,48 @@ export class Model {
   public readonly modelId: string;
   public readonly displayName: string;
   public readonly tags?: string[];
-  public readonly createTime: number;
-  public readonly updateTime: number;
+  public readonly createTime: string;
+  public readonly updateTime: string;
   public readonly validationError?: string;
   public readonly published: boolean;
   public readonly etag: string;
-  public readonly modelHash: string;
+  public readonly modelHash?: string;
+
+  public readonly tfliteModel?: TFLiteModel;
+
+  constructor(model: ModelResponse) {
+    if (!validator.isNonNullObject(model) ||
+      !validator.isNonEmptyString(model.name) ||
+      !validator.isNonEmptyString(model.createTime) ||
+      !validator.isNonEmptyString(model.updateTime) ||
+      !validator.isNonEmptyString(model.displayName) ||
+      !validator.isNonEmptyString(model.etag)) {
+        throw new FirebaseMachineLearningError(
+          'invalid-argument',
+          `Invalid Model response: ${JSON.stringify(model)}`);
+    }
+
+    this.modelId = extractModelId(model.name);
+    this.displayName = model.displayName;
+    this.tags = model.tags || [];
+    this.createTime = new Date(model.createTime).toUTCString();
+    this.updateTime = new Date(model.updateTime).toUTCString();
+    if (model.state?.validationError?.message) {
+      this.validationError = model.state?.validationError?.message;
+    }
+    this.published = model.state?.published || false;
+    this.etag = model.etag;
+    if (model.modelHash) {
+      this.modelHash = model.modelHash;
+    }
+    if (model.tfliteModel) {
+      this.tfliteModel = {
+        gcsTfliteUri: model.tfliteModel.gcsTfliteUri,
+        sizeBytes: model.tfliteModel.sizeBytes,
+      };
+    }
 
-  public readonly tfLiteModel?: TFLiteModel;
+  }
 
   public get locked(): boolean {
     // Backend does not currently return locked models.
@@ -211,9 +252,13 @@ export class ModelOptions {
   public displayName?: string;
   public tags?: string[];
 
-  public tfLiteModel?: { gcsTFLiteUri: string; };
+  public tfliteModel?: { gcsTFLiteUri: string; };
 
   protected toJSON(forUpload?: boolean): object {
     throw new Error('NotImplemented');
   }
 }
+
+function extractModelId(resourceName: string): string {
+  return resourceName.split('/').pop()!;
+}

test/integration/machine-learning.spec.ts

@@ -0,0 +1,34 @@
+/*!
+ * Copyright 2020 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import * as admin from '../../lib/index';
+
+describe('admin.machineLearning', () => {
+  describe('getModel()', () => {
+    it('rejects with not-found when the Model does not exist', () => {
+      const nonExistingName = '00000000';
+      return admin.machineLearning().getModel(nonExistingName)
+        .should.eventually.be.rejected.and.have.property(
+          'code', 'machine-learning/not-found');
+    });
+
+    it('rejects with invalid-argument when the ModelId is invalid', () => {
+      return admin.machineLearning().getModel('invalid-model-id')
+        .should.eventually.be.rejected.and.have.property(
+          'code', 'machine-learning/invalid-argument');
+    });
+  });
+});