Add update metric image API

doc/api/issues.md

@@ -2480,6 +2480,39 @@ Example response:
 ]
 ```
 
+## Update metric image
+
+Available only for Incident issues.
+
+```plaintext
+PUT /projects/:id/issues/:issue_iid/metric_images/:image_id
+```
+
+| Attribute   | Type    | Required | Description                          |
+|-------------|---------|----------|--------------------------------------|
+| `id`        | integer/string | yes      | The ID or [URL-encoded path of the project](index.md#namespaced-path-encoding) owned by the authenticated user  |
+| `issue_iid` | integer | yes      | The internal ID of a project's issue |
+| `image_id` | integer | yes      | The ID of the image |
+| `url` | string | no      | The URL to view more metric information |
+| `url_text` | string | no      | A description of the image or URL |
+
+```shell
+curl --header "PRIVATE-TOKEN: <your_access_token>" --request PUT  --form 'url=http://example.com' --form 'url_text=Example website' "https://gitlab.example.com/api/v4/projects/5/issues/93/metric_images/1"
+```
+
+Example response:
+
+```json
+{
+    "id": 23,
+    "created_at": "2020-11-13T00:06:18.084Z",
+    "filename": "file.png",
+    "file_path": "/uploads/-/system/issuable_metric_image/file/23/file.png",
+    "url": "http://example.com",
+    "url_text": "Example website"
+}
+```
+
 ## Delete metric image
 
 Available only for Incident issues.

ee/lib/ee/api/issues.rb

@@ -72,6 +72,30 @@ module EE
               end
             end
 
+            desc 'Update a metric image for an issue' do
+              success Entities::IssuableMetricImage
+            end
+            params do
+              requires :metric_image_id, type: Integer, desc: 'The ID of metric image'
+              optional :url, type: String, desc: 'The url to view more metric info'
+              optional :url_text, type: String, desc: 'A description of the image or URL'
+            end
+            put ':metric_image_id' do
+              issue = find_project_issue(params[:issue_iid])
+
+              authorize!(:destroy_issuable_metric_image, issue)
+
+              metric_image = issue.metric_images.find_by_id(params[:metric_image_id])
+
+              render_api_error!('Metric image not found', 404) unless metric_image
+
+              if metric_image&.update(params.slice(:url, :url_text))
+                present metric_image, with: Entities::IssuableMetricImage, current_user: current_user, project: user_project
+              else
+                render_api_error!('Metric image could not be updated', 400)
+              end
+            end
+
             desc 'Remove a metric image for an issue' do
               success Entities::IssuableMetricImage
             end

ee/spec/requests/api/issues_spec.rb

@@ -739,6 +739,104 @@ RSpec.describe API::Issues, :mailer do
     end
   end
 
+  describe 'PUT /projects/:id/issues/:issue_iid/metric_images/:metric_image_id' do
+    using RSpec::Parameterized::TableSyntax
+
+    let_it_be(:project) do
+      create(:project, :public, creator_id: user.id, namespace: user.namespace)
+    end
+
+    let!(:image) { create(:issuable_metric_image, issue: issue) }
+    let(:params) { { url: 'http://test.example.com', url_text: 'Example website 123' } }
+
+    subject { put api("/projects/#{project.id}/issues/#{issue.iid}/metric_images/#{image.id}", user2), params: params }
+
+    shared_examples 'can_update_metric_image' do
+      it 'can update the metric images' do
+        subject
+
+        expect(response).to have_gitlab_http_status(:success)
+        expect(json_response['url']).to eq(params[:url])
+        expect(json_response['url_text']).to eq(params[:url_text])
+      end
+    end
+
+    shared_examples 'unauthorized_update' do
+      it 'cannot delete the metric image' do
+        subject
+
+        expect(response).to have_gitlab_http_status(:forbidden)
+        expect(image.reload).to eq(image)
+      end
+    end
+
+    shared_examples 'not_found' do
+      it 'cannot delete the metric image' do
+        subject
+
+        expect(response).to have_gitlab_http_status(:not_found)
+        expect(image.reload).to eq(image)
+      end
+    end
+
+    where(:user_role, :own_issue, :issue_confidential, :expected_status) do
+      :not_member | false | false | :unauthorized_update
+      :not_member | true  | false | :unauthorized_update
+      :not_member | true  | true  | :unauthorized_update
+      :guest      | false | true  | :not_found
+      :guest      | false | false | :unauthorized_update
+      :guest      | true  | false | :can_update_metric_image
+      :reporter   | true  | false | :can_update_metric_image
+      :reporter   | false | false | :can_update_metric_image
+    end
+
+    with_them do
+      before do
+        stub_licensed_features(incident_metric_upload: true)
+        project.send("add_#{user_role}", user2) unless user_role == :not_member
+      end
+
+      let!(:issue) do
+        author = own_issue ? user2 : user
+        confidential = issue_confidential
+
+        create(:incident, project: project, confidential: confidential, author: author)
+      end
+
+      it_behaves_like "#{params[:expected_status]}"
+    end
+
+    context 'user has access' do
+      let(:issue) { create(:incident, project: project) }
+
+      before do
+        project.add_reporter(user2)
+      end
+
+      context 'metric image not found' do
+        subject { delete api("/projects/#{project.id}/issues/#{issue.iid}/metric_images/#{non_existing_record_id}", user2) }
+
+        it 'returns an error' do
+          subject
+
+          expect(response).to have_gitlab_http_status(:not_found)
+          expect(json_response['message']).to eq('Metric image not found')
+        end
+      end
+
+      context 'metric image cannot be updated' do
+        let(:params) { { url_text: 'something_long' * 100 } }
+
+        it 'returns an error' do
+          subject
+
+          expect(response).to have_gitlab_http_status(:bad_request)
+          expect(json_response['message']).to eq('Metric image could not be updated')
+        end
+      end
+    end
+  end
+
   describe 'DELETE /projects/:id/issues/:issue_iid/metric_images/:metric_image_id' do
     using RSpec::Parameterized::TableSyntax