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fix: adjust the backend plugin docs for new backend

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Signed-off-by: web-next-automation <web-platform@doordash.com>
Signed-off-by: aramissennyeydd <aramis.sennyey@doordash.com>
This commit is contained in:
web-next-automation
2024-04-07 19:26:17 -04:00
committed by aramissennyeydd
parent 401be8c3a4
commit 335151a281
1 changed files with 78 additions and 67 deletions
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docs/plugins/backend-plugin.md
+78 -67
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@@ -44,7 +44,7 @@ cd plugins/carmen-backend
yarn start
```
> Note: this documentation assumes you are using the latest version of Backstage and the new backend system. If you are not please upgrade and migrate your backend using the [Migration Guide](../backend-system/building-backends/08-migrating.md)
> Note: this documentation assumes you are using the latest version of Backstage and the new backend system. If you are not, please upgrade and migrate your backend using the [Migration Guide](../backend-system/building-backends/08-migrating.md)
This will think for a bit, and then say `Listening on :7007`. In a different
terminal window, now run
@@ -72,38 +72,19 @@ to your backend.
yarn --cwd packages/backend add @internal/plugin-carmen-backend@^0.1.0 # Change this to match the plugin's package.json
```
Create a new file named `packages/backend/src/plugins/carmen.ts`, and add the
following to it
Update `packages/backend/src/index` with the following,
```ts
import { createRouter } from '@internal/plugin-carmen-backend';
import { Router } from 'express';
import { PluginEnvironment } from '../types';
const backend = createBackend();
export default async function createPlugin(
env: PluginEnvironment,
): Promise<Router> {
// Here is where you will add all of the required initialization code that
// your backend plugin needs to be able to start!
// The env contains a lot of goodies, but our router currently only
// needs a logger
return await createRouter({
logger: env.logger,
});
}
```
And finally, wire this into the overall backend router. Edit
`packages/backend/src/index.ts`:
```ts
import carmen from './plugins/carmen';
// ...
async function main() {
// ...
const carmenEnv = useHotMemoize(module, () => createEnv('carmen'));
apiRouter.use('/carmen', await carmen(carmenEnv));
// highlight-add-next-line
backend.add(import('@internal/plugin-carmen-backend'));
// ...
backend.start();
```
After you start the backend (e.g. using `yarn start-backend` from the repo
@@ -122,30 +103,48 @@ The Backstage backend comes with a builtin facility for SQL database access.
Most plugins that have persistence needs will choose to make use of this
facility, so that Backstage operators can manage database needs uniformly.
As part of the environment object that is passed to your `createPlugin`
function, there is a `database` field. You can use that to get a
[Knex](http://knexjs.org/) connection object.
You can access this by adding a dependency on the `coreServices.database` service.
That will give you a [Knex](http://knexjs.org/) connection object.
```ts
// in packages/backend/src/plugins/carmen.ts
export default async function createPlugin(
env: PluginEnvironment,
): Promise<Router> {
const db: Knex<any, unknown[]> = await env.database.getClient();
// You will then pass this client into your actual plugin implementation
// code, maybe similar to the following:
const model = new CarmenDatabaseModel(db);
return await createRouter({
model: model,
logger: env.logger,
});
}
```ts title="plugins/carmen-backend/src/plugin.ts"
export const carmenPlugin = createBackendPlugin({
pluginId: 'carmenPlugin',
register(env) {
env.registerInit({
deps: {
httpRouter: coreServices.httpRouter,
logger: coreServices.logger,
// highlight-next-line
database: coreServices.database,
},
async init({
httpRouter,
logger,
// highlight-next-line
database,
}) {
// You will then pass this client into your actual plugin implementation
// code, maybe similar to the following:
const model = new CarmenDatabaseModel(db);
httpRouter.use(
await createRouter({
// highlight-next-line
model,
logger,
}),
);
httpRouter.addAuthPolicy({
path: '/health',
allow: 'unauthenticated',
});
},
});
},
});
```
You may note that the `getClient` call has no parameters. This is because all
plugin database needs are configured under the `backend.database` config key of
your `app-config.yaml`. The framework may even make sure behind the scenes that
All plugin database needs are configured under the `backend.database` config key
of your `app-config.yaml`. The framework may even make sure behind the scenes that
the logical database is created automatically if it doesn't exist, based on
rules that the Backstage operator decides on.
@@ -159,24 +158,36 @@ database..
## Making Use of the User's Identity
The Backstage backend comes with a facility for retrieving the identity of the
logged in user.
The Backstage backend also offers a core service to access the user's identity. You can access it through the `coreServices.identity` dependency.
As part of the environment object that is passed to your `createPlugin`
function, there is a `identity` field. You can use that to get an identity
from the request.
```ts
// in packages/backend/src/plugins/carmen.ts
export default async function createPlugin(
env: PluginEnvironment,
): Promise<Router> {
return await createRouter({
model: model,
logger: env.logger,
identity: env.identity,
});
}
```ts title="plugins/carmen-backend/src/plugin.ts"
export const carmenPlugin = createBackendPlugin({
pluginId: 'carmenPlugin',
register(env) {
env.registerInit({
deps: {
httpRouter: coreServices.httpRouter,
logger: coreServices.logger,
// highlight-next-line
identity: coreServices.identity,
},
async init({
httpRouter,
logger,
// highlight-next-line
identity,
}) {
httpRouter.use(
await createRouter({
// highlight-next-line
identity,
logger,
}),
);
},
});
},
});
```
The plugin can then extract the identity from the request.