Graphql schema storage as dockerized on-premise service for federated graphql gateway server (based on apollo server) as alternative to Apollo studio

• Stores versioned schema for graphql-federated services
• Serves schema for graphql gateway based on provided services & their versions
• Validates new schema to be compatible with other running services
• Provides UI for developers to see stored schema & its history diff
• Stores & shows in UI persisted queries passed by the gateway for debugging
• Stores service urls emulating managed federation: you no longer need to hardcode the services in your gateway's constructor, or rely on an additonal service (etcd, consul) for service discovery
• Async schema registration of new schema with events to avoid polling (schema-registry -> kafka -> gateway)

(Pull requests are encouraged on these topics)

• Usage tracking (to avoid breaking changes) - needs a separate docker sub-process in golang
  • registered clients (based on headers, including apollo-* ones)
  • schema usage breakdown by multiple facets - property, day, query name, client name
  • fixed data retention
• schema linting rules (camelCase, mandatory descriptions, too big objects, inconsistent pagination, dates not in DateTime...)
  • integrate inspector
• Performance tracking (to know what resolvers to optimize)
• access control - lightweight authentication in case this internal tool is publicly accessible
• separate ephemeral automatic PQs, registered by frontend (use cache only with TTL) from true PQs backend-registered persisted queries (use DB only)

We use environment variables for configuration. You can:

• pass them directly
• add .env file and dotenv will pick them up
• add them to docker-compose.yml or Dockerfile

The following are the different environment variables that are looked up that allow configuring the schema registry in different ways.

For development we rely on docker network and use hostnames from docker-compose.yml. Node service uses to connect to mysql & redis and change it if you install it with own setup. For dynamic service discovery (if you need multiple hosts for scaling), override app/config.js and diplomat.js

With default settings, UI should be accessible at http://localhost:6001

git clone https://github.com/pipedrive/graphql-schema-registry.git && cd graphql-schema-registry
cp example.env .env && nano .env
node app/schema-registry.js

We have docker image published for main node service. It assumes you have mysql/redis running separately. Use exact IP instead of localhost. Use exact docker image tag to avoid breaking changes.

docker pull pipedrive/graphql-schema-registry:3.0.1
docker run -e DB_HOST=localhost -e DB_USERNAME=root -e DB_PORT=6000 -p 6001:3000 pipedrive/graphql-schema-registry

git clone https://github.com/pipedrive/graphql-schema-registry.git && cd graphql-schema-registry
docker-compose up

On pre-commit / deploy make a POST /schema/validate to see if its compatible with current schema.

On service start-up (runtime), make POST to /schema/push to register schema (see API reference for details). Make sure to handle failure.

See example for nodejs/ESM.

If service A contains schema that needs to be migrated to service B, we need to orchestrate schema & traffic change. Instead of juggling with schema status flags, we suggest the following scenario:

• service B gets deployed with new schema which includes cycle of attempts to register new schema (for example every 5 sec).
• schema-registry responds with validation errors
• service A without conflicting schema gets deployed & updates schema-registry
• service B manages to register new schema & stops the cycle

graphql-schema-registry service is one of the components for graphql federation, but it needs tight integration with gateway. Check out examples folder on how to implement it. Note however, that gateway is very simplified and does not have proper error handling, cost limits or fail-safe mechanisms.

In gateway, you may also find useful our graphql-query-cost library too. Check it out

Migrations are done using knex

nvm use
npm install
npm run build
docker-compose -f docker-compose.dev.yml up

To have fast iteration of working on UI changes, you can avoid running node service in docker, and run only mysql & redis

docker-compose -f docker-compose.light.yml up
npm run develop

To create new DB migration, use:

npm run new-db-migration

If not using the default configuration of executing DB migrations on service startup, you can run the following npm command prior to starting the registry:

npm run migrate-db

The command can be prefixed with any environment variable necessary to configure DB connection (in case you ALTER DB with another user), such as:

DB_HOST=my-db-host DB_PORT=6000 npm run migrate-db

Unit tests use jest, coverage is quite low as most logic is in db or libraries.

npm run test-unit

Functional tests require docker, mostly blackbox type - real http requests are done against containers. DB tables are truncated after every test from within test/functional/bootstrap.js Jest runs in single worker mode to avoid tests from affecting each other due to same state.

npm run test-functional

• Commit often (instead of making huge commits)
• Add verb at the beginning of commit message
• Add why you're doing something in commit message
• Reference issues
• When making a pull request, be sure to follow the format of what is the problem you're fixing, what was changed & how to test it. Screenshots/videos are a welcome
• Fill CHANGELOG
• To avoid vulnerabilities, please use fixed versions in package.json

Current maintainer - @tot-ra. Mention in PR, if it is stuck

Original internal mission that resulted in this project going live:

• aleksandergasna
• ErikSchults
• LexSwed

See main blog post

Simplified version of /schema/compose where latest versions from different services is composed. Needed mostly for debugging

Lists schema based on passed services & their versions. Used by graphql gateway to fetch schema based on current containers

{
  "services": [
    { "name": "service_a", "version": "ke9j34fuuei" },
    { "name": "service_b", "version": "e302fj38fj3" }
  ]
}

• ✅ 200

{
  "success": true,
  "data": [
    {
      "id": 2,
      "service_id": 3,
      "version": "ke9j34fuuei",
      "name": "service_a",
      "url": "http://localhost:6111",
      "added_time": "2020-12-11T11:59:40.000Z",
      "type_defs": "\n\ttype Query {\n\t\thello: String\n\t}\n",
      "is_active": 1
    },
    {
      "id": 3,
      "service_id": 4,
      "version": "v1",
      "name": "service_b",
      "url": "http://localhost:6112",
      "added_time": "2020-12-14T18:51:04.000Z",
      "type_defs": "type Query {\n  world: String\n}\n",
      "is_active": 1
    }
  ]
}

• ❌ 400 "services[0].version" must be a string
• ❌ 500 Internal error (DB is down)

• services{ name, version}

If services is not passed, schema-registry tries to find most recent versions. Logic behind the scenes is that schema with highest added_time OR updated_time is picked as latest. If time is the same, schema.id is used.

Validates and registers new schema for a service.

{
  "name": "service_a",
  "version": "ke9j34fuuei",
  "type_defs": "\n\ttype Query {\n\t\thello: String\n\t}\n"
}

URL is optional if you use urls from schema-registry as service discovery

{
  "name": "service_b",
  "version": "jiaj51fu91k",
  "type_defs": "\n\ttype Query {\n\t\tworld: String\n\t}\n",
  "url": "http://service-b.develop.svc.cluster.local"
}

Validates schema, without adding to DB

• name
• version
• type_defs

Compares schemas and finds breaking or dangerous changes between provided and latest schemas.

• name
• version
• type_defs

Deletes specified schema

Deletes specified service including all schemas registered for that service

Looks up persisted query from DB & caches it in redis if its found

Adds persisted query to DB & redis cache