modelorama
v0.0.15
Published
Tame schemas once and for all!
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Modelorama showcases Protobuf, GraphQL and JSON-Schema cooperating to achieve a solid service-based architecture for web applications.
- The database is built on top of Sequelize, also powered by JSON-Schema
- The front-end API talks GraphQL while communication between back-end services is done through gRPC (optional)
- The implemented APIs can be written or consumed in TypeScript, by following the suggested architecture typings are granted (optional)
Install grown
and modelorama
globally or in your project:
npm i grown modelorama --save # or `npm i -g grown modelorama`
To begin with, just write the main db/app.js
file:
const Grown = require('grown')();
Grown.use(require('.'));
Grown.use(require('modelorama'));
module.exports = Grown.ready();
Here we're also registering
modelorama
to enable the discovery ofdb/resolvers
anddb/handlers
if GraphQL and gRPC are enabled respectively.
Now write a db/index.js
file with the following code:
module.exports = require('./generated')(require('modelorama')
.setup({
refs: require('./generated').default,
config: {
dialect: 'sqlite',
storage: '/tmp/db.sqlite',
directory: __dirname,
},
}));
This script will be used as module, it loads and configures the database repository.
Finally, you'll need to write a server.js
file:
module.exports = async () => {
const Grown = await require('./db/app');
const server = new Grown();
server.on('listen', app => {
console.log(app.location.href);
});
return server;
};
The later script will let you start the application server with
pot server start
— try runningmdl
without arguments to list all available tasks and options.
If you want to start the server manually (e.g. PORT=1234 node server
), then modify the script as follows:
-module.exports = server;
+if (require.main !== module) {
+ module.exports = server;
+} else {
+ server.listen(process.env.PORT || 8080);
+}
By default, we're gonna place all the related sources together, i.e. the db
directory:
- Model and their JSON-Schema definitions at
db/models
- GraphQL resolvers at
db/resolvers
(optional) - gRPC handlers at
db/handlers
(optional)
Types and Schemas
Lets add a type:
pot generate type db/types/dataTypes.yml pk primaryKey autoIncrement type:integer
Now create a model:
pot generate model db/models/User id:dataTypes/pk email:string password:string
Run
pot build schema db
to generate the required sources.
Try the interactive console with
pot console db
to debug your models — runUser.sync({ force: true })
to recreate the model if does not exists already!
Database migrations
In order to properly migrate the database from the previous steps you MUST:
- Run
pot migrate db --make
to create the migration files. - Run
pot migrate db --up
to execute those migrations. - Run
pot migrate db --apply "initial version"
to take a snapshot.
Every modification on the schemas should be followed by repeating the steps described above to ensure atomic changes over time — use
git commit
to keep your changes.
The db/schema.js
file is a single-shot migration or snapshot from the current database shape.
Snapshots are faster than running all migrations from ground up — try
pot migrate db --create
to recreate the database from scratch.
TypeScript usage
Run pot build types db
to generate the types from the current modules.
Now, you can import the types used in your code:
import Grown from './db/app';
import type { UserModel } from './db/app';
async function main() {
await Grown.Models.connect();
const User = Grown.Models.get<UserModel>('User');
await User.sync({ force: true });
const c = await User.count();
console.log(c);
}
main();
Also you can type the whole connection at once:
import Grown from './db/app';
import Modelorama from 'modelorama';
import type { DB, User } from './db/app';
Grown.use(require('@grown/model'));
const Models = await Modelorama.setup<DB>(Grown, {
config: {
dialect: 'sqlite',
storage: '/tmp/db.sqlite',
directory: `${__dirname}/db`,
},
});
const UserModel = Models.get('User').getSchema<User>();
console.log(UserModel.fakeOne({ alwaysFakeOptionals: true }));
We have types and schemas to build our model definitions, later we can declare (optionally) services for GraphQL and gRPC.
— Types are declared in JSON-Schema:
{
"id": "Example",
"type": "object",
"properties": {
"name": {
"type": "string"
}
},
"required": ["name"]
}
This can be traduced to GraphQL:
type Example {
name: String!
}
Protobuf can be generated the same way:
message Example {
required string name = 1;
}
As well its corresponding TypeScript type:
export type Example = {
name: string;
}
All this means:
- JSON-Schema is used to validate shape, format, content and advanced relationships as data.
- GraphQL and Protobuf can be used to validate shape and types on any message being transmitted.
- TypeScript can check your code with the proper types, just regenerate them if you update the schema.
— Services can be expressed using JSON or YAML:
id: Test
service:
calls:
- get: example
resp: Example
- get: examples
resp: ExampleList
definitions:
Example: !include schema.json
ExampleList:
type: array
items:
$ref: Example
Test
is not a schema because it lacks ofproperties
, it cannot be used as$ref
.
As you've pictured it, we'll get a working GraphQL declaration with its corresponding Protobuf service definition and TypeScript types, etc.
Service calls
are used to declare how gRPC and GraphQL will communicate, when omitted, you can also get rid of their handlers and resolvers, respectively.
GraphQL and gRPC integrations are completely optional.
Services usage
Definitions made for GraphQL and gRPC are available as middleware.
To make them work, you need to register them in your server.js
script:
server.on('listen', app => {
console.log(app.location.href);
});
+
+require('modelorama').plug(Grown, server);
+
+server.plug(require('modelorama').db(Grown));
Respectively:
plug(Container, serverInstance)
— will load and register the required modules for the enabled features, models are always booted upon connection.db(Container)
— returns a middleware that responds to/db
for scaffolding purposes; it helps to quickly create, read, update and delete data from your registered models.
Handlers and Resolvers
Lets generate a service for listing users:
pot generate service db/models/User/resource.yml get:users resp:UserList
Now, lets add the required types:
pot generate type db/models/User/resource.yml UserList type:array items:User
Generate the GraphQL resolver:
pot generate def db/resolvers/User Query.users --use API --args ctx
Generate the gRPC handler:
pot generate def db/handlers/User users --use User --args ctx
Provider for GraphQL resolvers:
pot generate def db/resolvers/provider.js API
Provider for gRPC handlers:
pot generate def db/handlers/provider.js User
Run
pot build schema db
to regenerate all model sources.
You'll need to update your db/index.js
script as well:
Grown.use(require('@grown/model'));
+ Grown.use(require('@grown/grpc'));
+ Grown.use(require('@grown/graphql'));
These modules are required to enable the services on the container.
At this point, you should be able to run pot server
without crashing... cheers!
But now, depending on the enabled services you should update the db/app.d.ts
types:
import type Models from './models';
+import type Handlers from './handlers';
+import type Resolvers from './resolvers';
...
export interface Server extends GrownInterface {
Models: Repository<Models>;
Services: Services;
+ Handlers: Handlers;
+ Resolvers: Resolvers;
}
Run
pot build types db
again to regenerate all types.
That's it! — now you should be able to import those modules with TypeScript, e.g.
import Grown from './db/app';
console.log(Grown.Models.get('User'));
console.log(Grown.Handlers.User.users.toString());
console.log(Grown.Resolvers.User.Query.users.toString());