Convex Component: LaunchDarkly


This is a Convex component for feature flagging and experimentation using
LaunchDarkly.

It syncs your LaunchDarkly environment to your Convex deployment, allowing you
to use your feature flags in Convex.

Why use LaunchDarkly with Convex?

- Feature flags in your backend: Use feature flags in your Convex functions
to dynamically control the behavior of your app.
- Experimentation: Run A/B tests and feature experiments in Convex using
LaunchDarkly.
- Real-time updates: Your LaunchDarkly flags and segments are synced to
Convex in real-time, so you can use them in your app without needing to make
additional API requests.

Prerequisites

$3

To use this component you must have a LaunchDarkly account.

$3

You'll need an existing Convex project to use the component. Convex is a hosted
backend platform, including a database, serverless functions, and a ton more you
can learn about here.

Run npm create convex or follow any of the
quickstarts to set one up.

Installation

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``bash
npm install @convex-dev/launchdarkly
`

Create a convex.config.ts file in your app's convex/ folder and install the
component by calling use:

`typescript
// convex/convex.config.ts
import { defineApp } from "convex/server";
import launchdarkly from "@convex-dev/launchdarkly/convex.config.js";

const app = defineApp();

app.use(launchdarkly);

export default app;
`

Once you've installed the component, make sure you push your changes to your
Convex app:

`bash
npx convex dev
`

Register webhooks by creating an http.ts file in your convex/ folder:

`typescript
// convex/http.ts
import { httpRouter } from "convex/server";
import { registerRoutes } from "@convex-dev/launchdarkly";
import { components } from "./_generated/api";

const http = httpRouter();

// You may pass a third parameter here to override the default path of /ld/webhook
registerRoutes(components.launchdarkly, http);

export default http;
`

This will register two webhook HTTP handlers in your your Convex app's
deployment:

- GET YOUR_CONVEX_SITE_URL/ld/webhook - LaunchDarkly will use this endpoint to
verify the installation of your component.
- PUT YOUR_CONVEX_SITE_URL/ld/webhook - LaunchDarkly will send your flag and
segment data to this endpoint.

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Now, you'll need to copy your LaunchDarkly environment's SDK Key and store it in
the component. You can copy your LaunchDarkly SDK by loading the
LaunchDarkly dashboard. From there visit your project's settings and copy the SDK key for your environment.

!Copy SDK Key

The value you copied should start with sdk-.

Store the SDK key you copied as an environment variable named
LAUNCHDARKLY_SDK_KEY in your Convex deployment. You can do so on the
environment variables
page or via npx convex env set LAUNCHDARKLY_SDK_KEY sdk-* from the CLI.

You can now configure the LaunchDarkly integration. On the
Integrations page
of the LaunchDarkly dashboard, search for Convex and click "Add Integration".

Each of your Convex deployments (e.g. Production and other developer's
environments) will need their own integration configured in LaunchDarkly.

!Add Integration

Select a name and environment for the integration.

For "Webhook URL", use your deployment's HTTP Actions URL suffixed with the path
provided to the registerRoutes call in your http.ts file. By default, the
path is /ld/webhook. You can retrieve your HTTP Actions URL on the
Deployment Settings page of
the Convex dashboard. Example:
https://techno-kitten-138.convex.site/ld/webhook

For "Component API Token", generate a shared secret to be used by the
LaunchDarkly integration. This will ensure the payloads sent to your webhook are
coming from LaunchDarkly.

`bash
npx convex run --component=launchdarkly tokens:generate --push
`

Once you save, you can open the integration form again and click the Validate
button to test the connection. If you encounter errors, check the logs page in
the Convex dashboard for more information.

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You may initialize the LaunchDarkly class with the component configuration and
use the LaunchDarkly SDK as you would in a normal JavaScript application.

`typescript
import { LaunchDarkly } from "@convex-dev/launchdarkly";
import { components } from "./_generated/api";
import { query } from "./_generated/server";

const launchdarkly = new LaunchDarkly(components.launchdarkly);

export const myQuery = query({
args: {},
handler: async ({ ctx }) => {
const ld = launchdarkly.sdk(ctx);
const isFlagOn = await ld.boolVariation(
"my-flag",
{ key: "myUser" },
false,
);
if (isFlagOn) {
// Do something when flag is on
} else {
// Do something when flag is off
}
},
});
`

Example App

You can run the example in the examples folder to see
how the LaunchDarkly component works.

Production

When you're ready to deploy your app to production with LaunchDarkly, be sure to
follow all the setup steps for production, including adding the
LAUNCHDARKLY_SDK_KEY evnironment variable and configuring an additional shared
secret and integration for Production. You'll want this to be configured before
any of your code relies on the LaunchDarkly flags.

You may use this command to generate your production secret:

`bash
npx convex run --component=launchdarkly --prod tokens:generate
`

Syncing multiple LaunchDarkly environments in one Convex app

If you have multiple LaunchDarkly environments, you can create a separate
component configuration for each environment.

`typescript
// convex/convex.config.js
import { defineApp } from "convex/server";
import launchdarkly from "@convex-dev/launchdarkly/convex.config.js";

const app = defineApp();

app.use(launchdarkly, {
name: "first",
});

app.use(launchdarkly, {
name: "second",
});

export default app;
`

Be sure to also update your http.ts file to register the routes for each
component:

`typescript
// convex/http.ts
import { httpRouter } from "convex/server";
import { registerRoutes } from "@convex-dev/launchdarkly";
import { components } from "./_generated/api";

const http = httpRouter();

registerRoutes(components.first, http, "/ld/first");
registerRoutes(components.second, http, "/ld/second");

export default http;
`

Then you can generate a separate shared secret for each environment:

`bash
npx convex run --component=first tokens:generate
npx convex run --component=second tokens:generate
`

Also, store the appropriate SDK keys in your Convex deployment for each
LaunchDarkly environment:

These secrets can be plugged into seperate integration configurations in
LaunchDarkly.

Once configured, you may initialize LaunchDarkly with the appropriate
component configuration:

`typescript
import { LaunchDarkly } from "@convex-dev/launchdarkly";

const launchDarklyFirst = new LaunchDarkly(components.first, {
LAUNCHDARKLY_SDK_KEY: process.env.LAUNCHDARKLY_SDK_KEY_FIRST!,
});

const launchDarklySecond = new LaunchDarkly(components.second, {
LAUNCHDARKLY_SDK_KEY: process.env.LAUNCHDARKLY_SDK_KEY_SECOND!,
});

export const myQuery = query({
args: {},
handler: async ({ ctx }) => {
const ldFirst = launchdarklyFirst.sdk(ctx);

const ldSecond = launchDarklySecond.sdk(ctx);

...
},
});
``

Unsupported LaunchDarkly features

The LaunchDarkly component for Convex is in beta, and may not support all
functionality available in the LaunchDarkly SDK. If you encounter any issues or
need help with a specific feature, please file an issue in the
GitHub repository.

- Sending events in Convex queries is not supported. If you would like to have
the SDK send events to LaunchDarkly (e.g. flag evaluation insights and for
experimentation), you should use LaunchDarkly in a mutation or action instead.
- Big segments
- Diagnostic events