# code-coverage-backend

This is the backend part of the `code-coverage` plugin. It takes care of processing various coverage formats and standardizing them into a single json format, used by the frontend.

## Installation

`yarn workspace backend add @backstage/plugin-code-coverage-backend`

First create a `codecoverage.ts` file here: `packages/backend/src/plugins`. Now add the following as its content:

```diff
diff --git a/packages/backend/src/plugins/codecoverage.ts b/packages/backend/src/plugins/codecoverage.ts
--- /dev/null
+++ b/packages/backend/src/plugins/codecoverage.ts
@@ -0,0 +1,15 @@
+import { createRouter } from '@backstage/plugin-code-coverage-backend';
+import { Router } from 'express';
+import { PluginEnvironment } from '../types';
+
+export default async function createPlugin(
+  env: PluginEnvironment,
+): Promise<Router> {
+  return await createRouter({
+    config: env.config,
+    discovery: env.discovery,
+    database: env.database,
+    urlReader: env.reader,
+    logger: env.logger,
+  });
+}

```

Finally we need to load the plugin in `packages/backend/src/index.ts`, make the following edits:

```diff
diff --git a/packages/backend/src/index.ts b/packages/backend/src/index.ts
--- a/packages/backend/src/index.ts
+++ b/packages/backend/src/index.ts
@@ -28,6 +28,7 @@ import scaffolder from './plugins/scaffolder';
 import proxy from './plugins/proxy';
 import techdocs from './plugins/techdocs';
 import search from './plugins/search';
+import codeCoverage from './plugins/codecoverage';
 import { PluginEnvironment } from './types';
 import { ServerPermissionClient } from '@backstage/plugin-permission-node';
 import { DefaultIdentityClient } from '@backstage/plugin-auth-node';
@@ -85,6 +86,9 @@ async function main() {
   const techdocsEnv = useHotMemoize(module, () => createEnv('techdocs'));
   const searchEnv = useHotMemoize(module, () => createEnv('search'));
   const appEnv = useHotMemoize(module, () => createEnv('app'));
+  const codeCoverageEnv = useHotMemoize(module, () =>
+    createEnv('code-coverage'),
+  );

   const apiRouter = Router();
   apiRouter.use('/catalog', await catalog(catalogEnv));
@@ -93,6 +97,7 @@ async function main() {
   apiRouter.use('/techdocs', await techdocs(techdocsEnv));
   apiRouter.use('/proxy', await proxy(proxyEnv));
   apiRouter.use('/search', await search(searchEnv));
+  apiRouter.use('/code-coverage', await codeCoverage(codeCoverageEnv));

   apiRouter.use(notFoundHandler());
```

## Configuring your entity

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

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

There's a feature to only include files that are in VCS 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
metadata:
  annotations:
    backstage.io/code-coverage: scm-only
```

Note: It may be required to set the [`backstage.io/source-location` annotation](https://backstage.io/docs/features/software-catalog/well-known-annotations#backstageiosource-location), however this should generally not be needed.

## API

### Adding a Cobertura report

POST a Cobertura XML file to `/report`

Example:

```json
// curl -X POST -H "Content-Type:text/xml" -d @cobertura.xml "localhost:7007/api/code-coverage/report?entity=component:default/entity-name&coverageType=cobertura"
{
  "links": [
    {
      "href": "http://localhost:7007/api/code-coverage/report?entity=component:default/entity-name",
      "rel": "coverage"
    }
  ]
}
```

### Adding a JaCoCo report

POST a JaCoCo XML file to `/report`

Example:

```json
// curl -X POST -H "Content-Type:text/xml" -d @jacoco.xml "localhost:7007/api/code-coverage/report?entity=component:default/entity-name&coverageType=jacoco"
{
  "links": [
    {
      "href": "http://localhost:7007/api/code-coverage/report?entity=component:default/entity-name",
      "rel": "coverage"
    }
  ]
}
```

### Reading json coverage

GET `/report`

Example:

```json
// curl localhost:7007/api/code-coverage/report?entity=component:default/entity-name
{
  "aggregate": {
    "branch": {
      "available": 0,
      "covered": 0,
      "missed": 0,
      "percentage": 0
    },
    "line": {
      "available": 5,
      "covered": 4,
      "missed": 1,
      "percentage": 80
    }
  },
  "entity": {
    "kind": "Component",
    "name": "entity-name",
    "namespace": "default"
  },
  "files": [
    {
      "branchHits": {},
      "filename": "main.go",
      "lineHits": {
        "117": 12,
        "142": 8,
        "34": 8,
        "42": 0,
        "58": 6
      }
    }
  ]
}
```

### Coverage history

GET `/history`

Example

```json
// curl localhost:7007/api/code-coverage/history?entity=component:default/entity-name
{
  "entity": {
    "kind": "Component",
    "name": "entity-name",
    "namespace": "default"
  },
  "history": [
    {
      "branch": {
        "available": 0,
        "covered": 0,
        "missed": 0,
        "percentage": 0
      },
      "line": {
        "available": 299,
        "covered": 116,
        "missed": 183,
        "percentage": 38.8
      },
      "timestamp": 1615490766141
    },
    {
      "branch": {
        "available": 0,
        "covered": 0,
        "missed": 0,
        "percentage": 0
      },
      "line": {
        "available": 299,
        "covered": 116,
        "missed": 183,
        "percentage": 38.8
      },
      "timestamp": 1615406307929
    }
  ]
}
```