Create code-coverage plugin

In order to use this plugin, you must set the
`backstage.io/code-coverage` annotation on your entity.

```yaml
backstage.io/code-coverage: enabled
```

There's a feature to only include files that are in SCM in the coverage
report, this is helpful to not count generated files for example. To
enable this set the `backstage.io/code-coverage` annotation to
`scm-only`.

```yaml
backstage.io/code-coverage: scm-only
```

The backend plugin provides API endpoints for submitting code-coverage
reports. Currently jacoco and cobertura are supported. These reports
are normalized to a json format that is stored in the database.

```json
// curl -X POST -H "Content-Type:text/xml" -d @cobertura.xml "localhost:7000/api/code-coverage/Component/default/entity-name?coverageType=cobertura"
{
    "links": [
        {
            "href": "http://localhost:7000/api/code-coverage/Component/default/entity-name",
            "rel": "coverage"
        }
    ]
}
```

It also provides some additional API endpoints:
* Viewing the latest report
* Viewing a more condensed history of code coverage values
* Retrieving file contents from source-control, used by the UI

Provides a graph of code coverage change over time, as well as a file
view where you can see the highlighted lines.

Co-authored-by: nissayeva <natashaaay@gmail.com>
Signed-off-by: alde <r.dybeck@gmail.com>
Signed-off-by: Fredrik Adelöw <freben@gmail.com>

packages/backend/package.json

@@ -35,6 +35,7 @@
     "@backstage/plugin-auth-backend": "^0.3.7",
     "@backstage/plugin-badges-backend": "^0.1.1",
     "@backstage/plugin-catalog-backend": "^0.7.0",
+    "@backstage/plugin-code-coverage-backend": "^0.1.0",
     "@backstage/plugin-graphql-backend": "^0.1.6",
     "@backstage/plugin-kubernetes-backend": "^0.3.3",
     "@backstage/plugin-kafka-backend": "^0.2.3",

packages/backend/src/index.ts

@@ -37,6 +37,7 @@ import { Config } from '@backstage/config';
 import healthcheck from './plugins/healthcheck';
 import auth from './plugins/auth';
 import catalog from './plugins/catalog';
+import codeCoverage from './plugins/codecoverage';
 import kubernetes from './plugins/kubernetes';
 import kafka from './plugins/kafka';
 import rollbar from './plugins/rollbar';
@@ -75,6 +76,9 @@ async function main() {
 
   const healthcheckEnv = useHotMemoize(module, () => createEnv('healthcheck'));
   const catalogEnv = useHotMemoize(module, () => createEnv('catalog'));
+  const codeCoverageEnv = useHotMemoize(module, () =>
+    createEnv('code-coverage'),
+  );
   const scaffolderEnv = useHotMemoize(module, () => createEnv('scaffolder'));
   const authEnv = useHotMemoize(module, () => createEnv('auth'));
   const proxyEnv = useHotMemoize(module, () => createEnv('proxy'));
@@ -90,6 +94,7 @@ async function main() {
 
   const apiRouter = Router();
   apiRouter.use('/catalog', await catalog(catalogEnv));
+  apiRouter.use('/code-coverage', await codeCoverage(codeCoverageEnv));
   apiRouter.use('/rollbar', await rollbar(rollbarEnv));
   apiRouter.use('/scaffolder', await scaffolder(scaffolderEnv));
   apiRouter.use('/auth', await auth(authEnv));

packages/backend/src/plugins/codecoverage.ts

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2020 Spotify AB
+ *
+ * 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 { createRouter } from '@backstage/plugin-code-coverage-backend';
+import { PluginEnvironment } from '../types';
+
+export default async function createPlugin(env: PluginEnvironment) {
+  return await createRouter({
+    config: env.config,
+    discovery: env.discovery,
+    database: env.database,
+    urlReader: env.reader,
+    logger: env.logger,
+  });
+}