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81 lines
3.6 KiB
Markdown
81 lines
3.6 KiB
Markdown
# Remote schemas
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Merge remote GraphQL schemas with GraphQL Engine's Postgres-based schema to query all your GraphQL types from the same endpoint. Remote schemas are ideal for use cases such as:
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* Customizing mutations (*e.g. running validations before inserts*)
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* Supporting features like payments, etc. and providing a consistent interface to access them i.e. behind the GraphQL Engine's API
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* Fetching disparate data from other sources (*e.g. from a weather API or another database*)
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To support custom business logic, you'll need to create a custom GraphQL server (see [boilerplates](community/boilerplates/graphql-servers)) and merge its schema with GraphQL Engine's.
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## Demo (*40 seconds*)
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[](https://www.youtube.com/watch?v=eY4n9aPsi0M)
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[Merge remote GraphQL schemas (YouTube link)](https://youtu.be/eY4n9aPsi0M)
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## Quickstart
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The fastest way to try remote schema out is via Heroku.
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1. Click on the following button to deploy GraphQL Engine on Heroku with the free Postgres add-on:
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[](https://heroku.com/deploy?template=https://github.com/hasura/graphql-engine-heroku)
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2. Open the Hasura console
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Visit `https://<app-name>.herokuapp.com` (*replace \<app-name\> with your app name*) to open the admin console.
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3. Merge your first remote schema and query it
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In the admin console, open the ``Remote Schemas`` tab and click on the ``Add`` button. Fill in the following details:
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* Remote Schema name: ``countries`` (*an alias for this remote schema*).
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* GraphQL server URL: ``https://countries.trevorblades.com/`` (*a public GraphQL API that we'll use to quickly check out this feature; maintained by [@trevorblades](https://github.com/trevorblades)*.
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* Ignore the remaining configuration settings and click on the ``Add Remote Schema`` button.
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Head to the ``GraphiQL` tab and run the following query (*paste it in the query window on the left and click the* ▶️ *(play) button*):
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```graphql
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{
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countries {
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emoji
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name
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languages {
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name
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native
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}
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}
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}
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```
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You can explore the GraphQL types from the remote schema using the ``Docs`` explorer in the top right corner of the ``GraphiQL`` interface.
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## Boilerplates
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Boilerplates for custom GraphQL servers in popular languages/frameworks are available.
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* [Regular boilerplates](community/boilerplates/graphql-servers) that can be deployed anywhere.
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* [Serverless boilerplates](https://github.com/hasura/graphql-serverless) that can deployed on serverless platforms like AWS Lambda, etc.
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Please note that boilerplates for more languages, frameworks, serverless platforms, etc. are being iterated upon and community contributions are very welcome.
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## Caveats
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**Current limitations**:
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* Nomenclature: Type names and node names need to be unique across all merged schemas (case-sensitive match). In the next few iterations, support for merging types with the exact same name and structure will be available.
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* Nodes from different GraphQL servers cannot be used in the same query/mutation. All top-level nodes have to be from the same GraphQL server.
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* Subscriptions on remote GraphQL server are not supported.
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* Interfaces are not supported - if a remote schema has interfaces, an error will be thrown if you try to merge it.
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These limitations will be addressed in upcoming versions.
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## Documentation
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Read the complete [documentation](https://docs.hasura.io/1.0/graphql/manual/remote-schemas/index.html).
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