Add new API endpoint to expose single environment

This is resolving https://gitlab.com/gitlab-org/gitlab-ce/issues/30157.

Implement new API endpoint `/projects/:id/environments/:environment_id`
to expose single environment. Include information for environment's last
deployment if there is one.

changelogs/unreleased/30157-api-expose-single-environment.yml

+---
+title: 'Add new API endpoint to expose a single environment.'
+merge_request: 26887
+author:
+type: added

doc/api/environments.md

@@ -29,6 +29,111 @@ Example response:
 ]
 ```
 
+## Get a specific environment
+
+```
+GET /projects/:id/environments/:environment_id
+```
+
+| Attribute | Type    | Required | Description         |
+|-----------|---------|----------|---------------------|
+| `id`      | integer/string | yes      | The ID or [URL-encoded path of the project](README.md#namespaced-path-encoding) owned by the authenticated user |
+| `environment_id` | integer | yes | The ID of the environment |
+
+```bash
+curl --header "PRIVATE-TOKEN: <your_access_token>" "https://gitlab.example.com/api/v4/projects/1/environments/1"
+```
+
+Example of response
+
+```json
+{
+  "id": 1,
+  "name": "review/fix-foo",
+  "slug": "review-fix-foo-dfjre3",
+  "external_url": "https://review-fix-foo-dfjre3.example.gitlab.com"
+  "last_deployment": {
+    "id": 100,
+    "iid": 34,
+    "ref": "fdroid",
+    "sha": "416d8ea11849050d3d1f5104cf8cf51053e790ab",
+    "created_at": "2019-03-25T18:55:13.252Z",
+    "user": {
+      "id": 1,
+      "name": "Administrator",
+      "state": "active",
+      "username": "root",
+      "avatar_url": "http://www.gravatar.com/avatar/e64c7d89f26bd1972efa854d13d7dd61?s=80&d=identicon",
+      "web_url": "http://localhost:3000/root"
+    }
+    "deployable": {
+      "id": 710,
+      "status": "success",
+      "stage": "deploy",
+      "name": "staging",
+      "ref": "fdroid",
+      "tag": false,
+      "coverage": null,
+      "created_at": "2019-03-25T18:55:13.215Z",
+      "started_at": "2019-03-25T12:54:50.082Z",
+      "finished_at": "2019-03-25T18:55:13.216Z",
+      "duration": 21623.13423,
+      "user": {
+        "id": 1,
+        "name": "Administrator",
+        "username": "root",
+        "state": "active",
+        "avatar_url": "http://www.gravatar.com/avatar/e64c7d89f26bd1972efa854d13d7dd61?s=80&d=identicon",
+        "web_url": "http://gitlab.dev/root",
+        "created_at": "2015-12-21T13:14:24.077Z",
+        "bio": null,
+        "location": null,
+        "public_email": "",
+        "skype": "",
+        "linkedin": "",
+        "twitter": "",
+        "website_url": "",
+        "organization": null
+      }
+      "commit": {
+        "id": "416d8ea11849050d3d1f5104cf8cf51053e790ab",
+        "short_id": "416d8ea1",
+        "created_at": "2016-01-02T15:39:18.000Z",
+        "parent_ids": [
+          "e9a4449c95c64358840902508fc827f1a2eab7df"
+        ],
+        "title": "Removed fabric to fix #40",
+        "message": "Removed fabric to fix #40\n",
+        "author_name": "Administrator",
+        "author_email": "admin@example.com",
+        "authored_date": "2016-01-02T15:39:18.000Z",
+        "committer_name": "Administrator",
+        "committer_email": "admin@example.com",
+        "committed_date": "2016-01-02T15:39:18.000Z"
+      },
+      "pipeline": {
+        "id": 34,
+        "sha": "416d8ea11849050d3d1f5104cf8cf51053e790ab",
+        "ref": "fdroid",
+        "status": "success",
+        "web_url": "http://localhost:3000/Commit451/lab-coat/pipelines/34"
+      },
+      "web_url": "http://localhost:3000/Commit451/lab-coat/-/jobs/710",
+      "artifacts": [
+        {
+          "file_type": "trace",
+          "size": 1305,
+          "filename": "job.log",
+          "file_format": null
+        }
+      ],
+      "runner": null,
+      "artifacts_expire_at": null
+    }
+  }
+}
+```
+
 ## Create a new environment
 
 Creates a new environment with the given name and external_url.

lib/api/entities.rb

@@ -1294,10 +1294,6 @@ module API
       expose :id, :name, :slug, :external_url
     end
 
-    class Environment < EnvironmentBasic
-      expose :project, using: Entities::BasicProjectDetails
-    end
-
     class Deployment < Grape::Entity
       expose :id, :iid, :ref, :sha, :created_at
       expose :user,        using: Entities::UserBasic
@@ -1305,6 +1301,11 @@ module API
       expose :deployable,  using: Entities::Job
     end
 
+    class Environment < EnvironmentBasic
+      expose :project, using: Entities::BasicProjectDetails
+      expose :last_deployment, using: Entities::Deployment, if: { last_deployment: true }
+    end
+
     class LicenseBasic < Grape::Entity
       expose :key, :name, :nickname
       expose :url, as: :html_url

lib/api/environments.rb

@@ -101,6 +101,21 @@ module API
         status 200
         present environment, with: Entities::Environment, current_user: current_user
       end
+
+      desc 'Get a single environment' do
+        success Entities::Environment
+      end
+      params do
+        requires :environment_id, type: Integer, desc: 'The environment ID'
+      end
+      get ':id/environments/:environment_id' do
+        authorize! :read_environment, user_project
+
+        environment = user_project.environments.find(params[:environment_id])
+        present environment, with: Entities::Environment, current_user: current_user,
+                             except: [:project, { last_deployment: [:environment] }],
+                             last_deployment: true
+      end
     end
   end
 end

spec/fixtures/api/schemas/public_api/v4/artifact.json

+{
+  "type": "object",
+  "required": [
+    "file_type",
+    "size",
+    "filename",
+    "file_format"
+  ],
+  "properties": {
+    "file_type": { "type": "string"},
+    "size": { "type": "integer"},
+    "filename": { "type": "string"},
+    "file_format": { "type": "string"}
+  },
+  "additionalProperties": false
+}

spec/fixtures/api/schemas/public_api/v4/artifact_file.json

+{
+  "type": "object",
+  "required": [
+    "filename",
+    "size"
+  ],
+  "properties": {
+    "filename": { "type": "string"},
+    "size": { "type": "integer"}
+  },
+  "additionalProperties": false
+}

spec/fixtures/api/schemas/public_api/v4/deployment.json

+{
+  "type": "object",
+  "required": [
+    "id",
+    "iid",
+    "ref",
+    "sha",
+    "created_at",
+    "user",
+    "deployable"
+  ],
+  "properties": {
+    "id": { "type": "integer" },
+    "iid": { "type": "integer" },
+    "ref": { "type": "string" },
+    "sha": { "type": "string" },
+    "created_at": { "type": "string" },
+    "user": {
+      "oneOf": [
+        { "type": "null" },
+        { "$ref": "user/basic.json" }
+      ]
+    },
+    "deployable": {
+      "oneOf": [
+        { "type": "null" },
+        { "$ref": "job.json" }
+      ]
+    }
+  },
+  "additionalProperties": false
+}

spec/fixtures/api/schemas/public_api/v4/environment.json

+{
+  "type": "object",
+  "required": [
+    "id",
+    "name",
+    "slug",
+    "external_url",
+    "last_deployment"
+  ],
+  "properties": {
+    "id": { "type": "integer" },
+    "name": { "type": "string" },
+    "slug": { "type": "string" },
+    "external_url": { "$ref": "../../types/nullable_string.json" },
+    "last_deployment": {
+      "oneOf": [
+        { "type": "null" },
+        { "$ref": "deployment.json" }
+      ]
+    }
+  },
+  "additionalProperties": false
+}

spec/fixtures/api/schemas/public_api/v4/job.json

+{
+  "type": "object",
+  "required": [
+    "id",
+    "status",
+    "stage",
+    "name",
+    "ref",
+    "tag",
+    "coverage",
+    "created_at",
+    "started_at",
+    "finished_at",
+    "duration",
+    "user",
+    "commit",
+    "pipeline",
+    "web_url",
+    "artifacts",
+    "artifacts_expire_at",
+    "runner"
+  ],
+  "properties": {
+    "id": { "type": "integer" },
+    "status": { "type": "string" },
+    "stage": { "type": "string" },
+    "name": { "type": "string" },
+    "ref": { "type": "string" },
+    "tag": { "type": "boolean" },
+    "coverage": { "type": ["number", "null"] },
+    "created_at": { "type": "string" },
+    "started_at": { "type": ["null", "string"] },
+    "finished_at": { "type": ["null", "string"] },
+    "duration": { "type": ["null", "number"] },
+    "user": { "$ref": "user/basic.json" },
+    "commit": {
+      "oneOf": [
+        { "type": "null" },
+        { "$ref": "commit/basic.json" }
+      ]
+    },
+    "pipeline": { "$ref": "pipeline/basic.json" },
+    "web_url": { "type": "string" },
+    "artifacts": {
+      "type": "array",
+      "items": { "$ref": "artifact.json" }
+    },
+    "artifacts_file": {
+      "oneOf": [
+        { "type": "null" },
+        { "$ref": "artifact_file.json" }
+      ]
+    },
+    "artifacts_expire_at": { "type": ["null", "string"] },
+    "runner": {
+      "oneOf": [
+        { "type": "null" },
+        { "$ref": "runner.json" }
+      ]
+    }
+  },
+  "additionalProperties":false
+}

spec/fixtures/api/schemas/public_api/v4/runner.json

+{
+  "type": "object",
+  "required": [
+    "id",
+    "description",
+    "ip_address",
+    "active",
+    "is_shared",
+    "name",
+    "online",
+    "status"
+  ],
+  "properties": {
+    "id": { "type": "integer" },
+    "description": { "type": "string" },
+    "ip_address": { "type": "string" },
+    "active": { "type": "boolean" },
+    "is_shared": { "type": "boolean" },
+    "name": { "type": ["null", "string"] },
+    "online": { "type": "boolean" },
+    "status": { "type": "string" }
+  },
+  "additionalProperties": false
+}

spec/requests/api/environments_spec.rb

@@ -32,6 +32,7 @@ describe API::Environments do
         expect(json_response.first['name']).to eq(environment.name)
         expect(json_response.first['external_url']).to eq(environment.external_url)
         expect(json_response.first['project'].keys).to contain_exactly(*project_data_keys)
+        expect(json_response.first).not_to have_key("last_deployment")
       end
     end
 
@@ -188,4 +189,25 @@ describe API::Environments do
       end
     end
   end
+
+  describe 'GET /projects/:id/environments/:environment_id' do
+    context 'as member of the project' do
+      it 'returns project environments' do
+        create(:deployment, :success, project: project, environment: environment)
+
+        get api("/projects/#{project.id}/environments/#{environment.id}", user)
+
+        expect(response).to have_gitlab_http_status(200)
+        expect(response).to match_response_schema('public_api/v4/environment')
+      end
+    end
+
+    context 'as non member' do
+      it 'returns a 404 status code' do
+        get api("/projects/#{project.id}/environments/#{environment.id}", non_member)
+
+        expect(response).to have_gitlab_http_status(404)
+      end
+    end
+  end
 end