enhance(runtime): support async return values in progressiveOverride

.changeset/strange-wolves-knock.md

@@ -0,0 +1,25 @@
+---
+'@graphql-mesh/fusion-runtime': minor
+'@graphql-tools/federation': minor
+'@graphql-hive/gateway-runtime': minor
+---
+
+Support promises in `progressiveOverride` option
+
+```ts
+import { defineConfig } from '@graphql-hive/gateway';
+export const gatewayConfig = defineConfig({
+    async progressiveOverride(label: string, context: GatewayContext) {
+        if (label === 'my_label') {
+            const serviceResponse = await fetch('http://example.com/should_override', {
+                headers: {
+                    'x-some-header': context.headers['x-some-header'],
+                }
+            });
+            const result = await serviceResponse.json();
+            return result?.override;
+        }
+        return false;
+    }
+})
+```

.github/workflows/examples.yml

@@ -54,6 +54,7 @@ jobs:
           - subscriptions-with-transforms
           - type-merging-batching
           - operation-field-permissions
+          - launchdarkly-override
           # TODO: support containers before enabling (we use nats image in e2e)
           # - event-driven-federated-subscriptions
     name: Convert ${{matrix.e2e}}

e2e/launchdarkly-override/gateway.config.ts

@@ -0,0 +1,82 @@
+import { defineConfig } from '@graphql-hive/gateway';
+import ld from '@launchdarkly/node-server-sdk';
+
+const {
+  LAUNCH_DARKLY_PROJECT_ID,
+  LAUNCH_DARKLY_ENVIRONMENT,
+  LAUNCH_DARKLY_REST_API_KEY,
+  LAUNCH_DARKLY_SDK_KEY,
+} = process.env;
+
+const LABEL_PREFIX = 'launchDarkly:';
+
+let flagValues: Record<string, number> = {};
+listenForFlagUpdates((name, value) => {
+  flagValues[name] = value;
+});
+
+export const gatewayConfig = defineConfig({
+  progressiveOverride(label) {
+    // ignore labels that don't start with our prefix
+    if (!label.startsWith(LABEL_PREFIX)) return false;
+    // remove prefix from label
+    const flagKey = label.substring(LABEL_PREFIX.length);
+    // find flagKey in flagValues and roll the dice to see if we should override
+    const flagValue = flagValues[flagKey];
+    if (!flagValue) return false;
+    return Math.random() * 100 < flagValue;
+  },
+});
+
+export async function listenForFlagUpdates(
+  listener: (name: string, value: number) => void,
+) {
+  if (
+    !LAUNCH_DARKLY_SDK_KEY ||
+    !LAUNCH_DARKLY_REST_API_KEY ||
+    !LAUNCH_DARKLY_PROJECT_ID ||
+    !LAUNCH_DARKLY_ENVIRONMENT
+  ) {
+    throw new Error('LaunchDarkly environment variables are not set');
+  }
+  const ldClient = ld.init(LAUNCH_DARKLY_SDK_KEY);
+  await ldClient.waitForInitialization();
+
+  const allFlagsResult = await (
+    await fetch(
+      `https://app.launchdarkly.com/api/v2/flags/${LAUNCH_DARKLY_PROJECT_ID}?env=${LAUNCH_DARKLY_ENVIRONMENT}`,
+      {
+        headers: {
+          Authorization: LAUNCH_DARKLY_REST_API_KEY,
+        },
+      },
+    )
+  ).json();
+
+  for (const flag of allFlagsResult.items) {
+    const ffKey = flag.key;
+    const variations =
+      flag.environments[LAUNCH_DARKLY_ENVIRONMENT]._summary.variations;
+    if (Object.keys(variations).length === 2 && variations['0'].rollout) {
+      listener(ffKey, variations['0'].rollout / 1000);
+    }
+  }
+
+  ldClient.on('update', async (param) => {
+    const updatedFlag = await (
+      await fetch(
+        `https://app.launchdarkly.com/api/v2/flags/${LAUNCH_DARKLY_PROJECT_ID}/${param.key}?env=${LAUNCH_DARKLY_ENVIRONMENT}`,
+        {
+          headers: {
+            Authorization: LAUNCH_DARKLY_REST_API_KEY,
+          },
+        },
+      )
+    ).json();
+    listener(
+      param.key,
+      updatedFlag.environments[LAUNCH_DARKLY_ENVIRONMENT].fallthrough.rollout
+        .variations[0].weight / 1000,
+    );
+  });
+}

e2e/launchdarkly-override/package.json

@@ -0,0 +1,11 @@
+{
+  "name": "@e2e/launchdarkly-override-example",
+  "private": true,
+  "dependencies": {
+    "@apollo/subgraph": "2.11.3",
+    "@launchdarkly/node-server-sdk": "9.10.2",
+    "graphql": "16.11.0",
+    "graphql-yoga": "5.16.0",
+    "tslib": "^2.8.1"
+  }
+}

e2e/launchdarkly-override/services/inventory.ts

@@ -0,0 +1,39 @@
+import { createServer } from 'http';
+import { buildSubgraphSchema } from '@apollo/subgraph';
+import { Opts } from '@internal/testing';
+import { parse } from 'graphql';
+import { createYoga } from 'graphql-yoga';
+
+const port = Opts(process.argv).getServicePort('inventory');
+
+createServer(
+  createYoga({
+    schema: buildSubgraphSchema({
+      typeDefs: parse(/* GraphQL */ `
+        type Product @key(fields: "id") {
+          id: ID!
+          inStock: Boolean
+            @override(from: "products", label: "use_inventory_service")
+          count: Int
+        }
+
+        extend schema
+          @link(
+            url: "https://specs.apollo.dev/federation/v2.7"
+            import: ["@key", "@override"]
+          )
+      `),
+      resolvers: {
+        Product: {
+          __resolveReference(reference: { id: string }) {
+            return {
+              id: reference.id,
+            };
+          },
+          inStock: () => true,
+          count: () => 42,
+        },
+      },
+    }),
+  }),
+).listen(port);

e2e/launchdarkly-override/services/products.ts

@@ -0,0 +1,43 @@
+import { createServer } from 'http';
+import { buildSubgraphSchema } from '@apollo/subgraph';
+import { Opts } from '@internal/testing';
+import { parse } from 'graphql';
+import { createYoga } from 'graphql-yoga';
+
+const port = Opts(process.argv).getServicePort('products');
+
+createServer(
+  createYoga({
+    schema: buildSubgraphSchema({
+      typeDefs: parse(/* GraphQL */ `
+        type Product @key(fields: "id") {
+          id: ID!
+          name: String
+          price: Float
+          inStock: Boolean
+        }
+
+        type Query {
+          product(id: ID!): Product
+        }
+      `),
+      resolvers: {
+        Product: {
+          __resolveReference(reference: { id: string }) {
+            return {
+              id: reference.id,
+            };
+          },
+          name: (parent: { id: string }) => `Product ${parent.id}`,
+          price: () => 9.99,
+          inStock: () => false,
+        },
+        Query: {
+          product(_: any, args: { id: string }) {
+            return { id: args.id };
+          },
+        },
+      },
+    }),
+  }),
+).listen(port);

e2e/launchdarkly-override/services/reviews.ts

@@ -0,0 +1,39 @@
+import { createServer } from 'http';
+import { buildSubgraphSchema } from '@apollo/subgraph';
+import { Opts } from '@internal/testing';
+import { parse } from 'graphql';
+import { createYoga } from 'graphql-yoga';
+
+const port = Opts(process.argv).getServicePort('reviews');
+
+createServer(
+  createYoga({
+    schema: buildSubgraphSchema({
+      typeDefs: parse(/* GraphQL */ `
+        type Review @key(fields: "id") {
+          id: ID!
+          content: String
+          product: Product
+        }
+
+        type Query {
+          reviews: [Review]
+        }
+
+        type Product @key(fields: "id") {
+          id: ID!
+        }
+      `),
+      resolvers: {
+        Query: {
+          reviews() {
+            return [
+              { id: '1', content: 'Great product!', product: { id: '101' } },
+              { id: '2', content: 'Not bad', product: { id: '102' } },
+            ];
+          },
+        },
+      },
+    }),
+  }),
+).listen(port);

e2e/progressive-override/gateway.config.ts

@@ -1,12 +1,21 @@
 import { defineConfig, GatewayContext } from '@graphql-hive/gateway';
 
+const labelServiceUrl = process.env['LABEL_SERVICE_URL'];
+
+if (!labelServiceUrl) {
+  throw new Error('LABEL_SERVICE_URL environment variable is not defined');
+}
+
 export const gatewayConfig = defineConfig({
-  progressiveOverride(label, context: GatewayContext) {
-    if (
-      label === 'use_inventory_service' &&
-      context.request.headers.get('x-use-inventory-service') === 'true'
-    ) {
-      return true;
+  async progressiveOverride(label, context: GatewayContext) {
+    if (label === 'use_inventory_service') {
+      const serviceRes = await fetch(labelServiceUrl, {
+        headers: {
+          'x-use-inventory-service':
+            context.headers['x-use-inventory-service'] || 'false',
+        },
+      }).then((res) => res.text());
+      return serviceRes === 'use_inventory_service';
     }
     return false;
   },

e2e/progressive-override/progressive-override.e2e.ts

@@ -1,9 +1,17 @@
-import { createTenv } from '@internal/e2e';
+import { createTenv, handleDockerHostNameInURLOrAtPath } from '@internal/e2e';
 import { describe, expect, it } from 'vitest';
 
-const { service, gateway } = createTenv(__dirname);
+const { service, gateway, gatewayRunner } = createTenv(__dirname);
 describe('Progressive Override E2E', async () => {
   it('overrides products if the header exists', async () => {
+    const labelService = await service('label');
+    let labelServiceUrl = `http://localhost:${labelService.port}`;
+    if (gatewayRunner.includes('docker')) {
+      labelServiceUrl = await handleDockerHostNameInURLOrAtPath(
+        labelServiceUrl,
+        [],
+      );
+    }
     const gw = await gateway({
       supergraph: {
         with: 'apollo',
@@ -13,6 +21,9 @@ describe('Progressive Override E2E', async () => {
           await service('reviews'),
         ],
       },
+      env: {
+        LABEL_SERVICE_URL: labelServiceUrl,
+      },
     });
     const result = await gw.execute({
       query: /* GraphQL */ `
@@ -58,8 +69,15 @@ describe('Progressive Override E2E', async () => {
     });
   });
   it('does not override products if the header does not exist', async () => {
+    const labelService = await service('label');
+    let labelServiceUrl = `http://localhost:${labelService.port}`;
+    if (gatewayRunner.includes('docker')) {
+      labelServiceUrl = await handleDockerHostNameInURLOrAtPath(
+        labelServiceUrl,
+        [],
+      );
+    }
     const gw = await gateway({
-      pipeLogs: 'gw.log',
       supergraph: {
         with: 'apollo',
         services: [
@@ -68,6 +86,9 @@ describe('Progressive Override E2E', async () => {
           await service('reviews'),
         ],
       },
+      env: {
+        LABEL_SERVICE_URL: labelServiceUrl,
+      },
     });
     const result = await gw.execute({
       query: /* GraphQL */ `

e2e/progressive-override/services/label.ts

@@ -0,0 +1,15 @@
+import { createServer } from 'http';
+import { Opts } from '@internal/testing';
+
+const port = Opts(process.argv).getServicePort('label');
+
+createServer((req, res) => {
+  res.writeHead(200, { 'Content-Type': 'text/plain' });
+  if (req.headers['x-use-inventory-service'] === 'true') {
+    res.end('use_inventory_service');
+  } else {
+    res.end('do_not_use_inventory_service');
+  }
+}).listen(port, () => {
+  console.log(`Label service is running at http://localhost:${port}/`);
+});