ENGCOM-2989: Recheck 129 retrive customer token #184

 - Merge Pull Request magento/graphql-ce#184 from magento/graphql-ce:recheck-129-retrive-customer-token
 - Merged commits:
   1. 527e4fe
   2. ea9b2a8
   3. ca0c135
   4. c0d1b7b
   5. e97301d
   6. 85cd239
   7. 6a250c1
   8. 21e719c
   9. ad388f6
   10. 277fe08
   11. 5dce3bd

app/code/Magento/CustomerGraphQl/Model/Resolver/Customer/Account/GenerateCustomerToken.php

@@ -0,0 +1,61 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\CustomerGraphQl\Model\Resolver\Customer\Account;
+
+use Magento\Framework\Exception\AuthenticationException;
+use Magento\Framework\GraphQl\Config\Element\Field;
+use Magento\Framework\GraphQl\Exception\GraphQlAuthorizationException;
+use Magento\Framework\GraphQl\Query\ResolverInterface;
+use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;
+use Magento\Integration\Api\CustomerTokenServiceInterface;
+
+/**
+ * Customers Token resolver, used for GraphQL request processing.
+ */
+class GenerateCustomerToken implements ResolverInterface
+{
+    /**
+     * @var CustomerTokenServiceInterface
+     */
+    private $customerTokenService;
+
+    /**
+     * @param CustomerTokenServiceInterface $customerTokenService
+     */
+    public function __construct(
+        CustomerTokenServiceInterface $customerTokenService
+    ) {
+        $this->customerTokenService = $customerTokenService;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    public function resolve(
+        Field $field,
+        $context,
+        ResolveInfo $info,
+        array $value = null,
+        array $args = null
+    ) {
+        try {
+            if (!isset($args['email'])) {
+                throw new GraphQlInputException(__('"email" value should be specified'));
+            }
+            if (!isset($args['password'])) {
+                throw new GraphQlInputException(__('"password" value should be specified'));
+            }
+            $token = $this->customerTokenService->createCustomerAccessToken($args['email'], $args['password']);
+            return ['token' => $token];
+        } catch (AuthenticationException $e) {
+            throw new GraphQlAuthorizationException(
+                __($e->getMessage())
+            );
+        }
+    }
+}

app/code/Magento/CustomerGraphQl/composer.json

@@ -6,6 +6,7 @@
     "php": "~7.1.3||~7.2.0",
     "magento/module-customer": "*",
     "magento/module-authorization": "*",
+    "magento/module-integration": "*",
     "magento/framework": "*"
   },
   "suggest": {

app/code/Magento/CustomerGraphQl/etc/schema.graphqls

@@ -5,6 +5,14 @@ type Query {
     customer: Customer @resolver(class: "Magento\\CustomerGraphQl\\Model\\Resolver\\Customer") @doc(description: "The customer query returns information about a customer account")
 }
 
+type Mutation {
+    generateCustomerToken(email: String!, password: String!): CustomerToken @resolver(class: "\\Magento\\CustomerGraphQl\\Model\\Resolver\\Customer\\Account\\GenerateCustomerToken") @doc(description:"Retrieve Customer token")
+}
+
+type CustomerToken {
+    token: String @doc(description: "The customer token")
+}
+
 type Customer @doc(description: "Customer defines the customer name and address and other details") {
     created_at: String @doc(description: "Timestamp indicating when the account was created")
     group_id: Int @doc(description: "The group assigned to the user. Default values are 0 (Not logged in), 1 (General), 2 (Wholesale), and 3 (Retailer)")

dev/tests/api-functional/testsuite/Magento/GraphQl/Customer/GenerateCustomerTokenTest.php

@@ -0,0 +1,71 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\GraphQl\Customer;
+
+use Magento\TestFramework\TestCase\GraphQlAbstract;
+use PHPUnit\Framework\TestResult;
+
+/**
+ * Class GenerateCustomerTokenTest
+ * @package Magento\GraphQl\Customer
+ */
+class GenerateCustomerTokenTest extends GraphQlAbstract
+{
+    /**
+     * Verify customer token with valid credentials
+     *
+     * @magentoApiDataFixture Magento/Customer/_files/customer.php
+     */
+    public function testGenerateCustomerValidToken()
+    {
+        $userName = 'customer@example.com';
+        $password = 'password';
+
+        $mutation
+            = <<<MUTATION
+mutation {
+	generateCustomerToken(
+        email: "{$userName}"
+        password: "{$password}"
+    ) {
+        token
+    }
+}
+MUTATION;
+
+        $response = $this->graphQlQuery($mutation);
+        $this->assertArrayHasKey('generateCustomerToken', $response);
+        $this->assertInternalType('array', $response['generateCustomerToken']);
+    }
+
+    /**
+     * Verify customer with invalid credentials
+     */
+    public function testGenerateCustomerTokenWithInvalidCredentials()
+    {
+        $userName = 'customer@example.com';
+        $password = 'bad-password';
+
+        $mutation
+            = <<<MUTATION
+mutation {
+	generateCustomerToken(
+        email: "{$userName}"
+        password: "{$password}"
+    ) {
+        token
+    }
+}
+MUTATION;
+
+        $this->expectException(\Exception::class);
+        $this->expectExceptionMessage('GraphQL response contains errors: The account sign-in' . ' ' .
+            'was incorrect or your account is disabled temporarily. Please wait and try again later.');
+        $this->graphQlQuery($mutation);
+    }
+}