services: create high-level builder module DbInstance (#36)

The name is TBC, but the behaviour is what we want to focus on right now

Author: devmatteini

packages/services/examples/db-instance.ts

@@ -0,0 +1,46 @@
+import * as DbInstance from "@effect-mongodb/services/DbInstance"
+import * as DbService from "@effect-mongodb/services/DbService"
+import * as Collection from "effect-mongodb/Collection"
+import * as Db from "effect-mongodb/Db"
+import * as FindCursor from "effect-mongodb/FindCursor"
+import * as Config from "effect/Config"
+import * as Effect from "effect/Effect"
+import * as Schema from "effect/Schema"
+
+const Todo = Schema.Struct({
+  userId: Schema.Number,
+  id: Schema.Number,
+  title: Schema.String,
+  completed: Schema.Boolean
+})
+
+const MyDb = DbService.Tag("MyDb")
+
+const program = Effect.gen(function*() {
+  const db = yield* MyDb
+  const sourceCollection = Db.collection(db, "source", Todo)
+  const destinationCollection = Db.collection(db, "destination", Todo)
+
+  const items = yield* Collection.find(sourceCollection).pipe(FindCursor.toArray)
+
+  yield* Collection.insertMany(destinationCollection, items)
+})
+
+/*** main.ts ***/
+
+const MyDbLive = DbInstance.layerEffect(
+  MyDb,
+  Effect.gen(function*() {
+    const databaseName = yield* Config.string("MONGO_DATABASE_NAME")
+    const clientUrl = yield* Config.string("MONGO_CONNECTION_STRING")
+    return {
+      database: { name: databaseName },
+      client: { url: clientUrl, timeoutMS: 5000 }
+    }
+  })
+)
+
+await program.pipe(
+  Effect.provide(MyDbLive),
+  Effect.runPromise
+)

packages/services/src/DbInstance.ts

@@ -0,0 +1,39 @@
+/**
+ * @since 0.0.1
+ */
+import type * as MongoClient from "effect-mongodb/MongoClient"
+import * as Effect from "effect/Effect"
+import * as F from "effect/Function"
+import * as Layer from "effect/Layer"
+import type { DbOptions } from "mongodb"
+import * as DbService from "./DbService.js"
+import * as MongoClientService from "./MongoClientService.js"
+
+type DbInstanceOptions = {
+  database: DbOptions & { name: string }
+  client: MongoClient.MongoClientScopedOptions & { url: string }
+}
+
+export const layerEffect = <DbK extends string, E = never, R = never>(
+  dbTag: DbService.TagType<DbK>,
+  options: Effect.Effect<DbInstanceOptions, E, R>
+) =>
+  F.pipe(
+    options,
+    Effect.map((options) => layer(dbTag, options)),
+    Layer.unwrapEffect
+  )
+
+export const layer = <DbK extends string>(
+  dbTag: DbService.TagType<DbK>,
+  options: DbInstanceOptions
+) => {
+  const { name: databaseName, ...databaseOptions } = options.database
+  const { url: clientUrl, ...clientOptions } = options.client
+
+  const dbLayer = DbService.layer(dbTag, DefaultMongoClient, databaseName, databaseOptions)
+  const defaultClientLayer = MongoClientService.layer(DefaultMongoClient, clientUrl, clientOptions)
+  return dbLayer.pipe(Layer.provide(defaultClientLayer))
+}
+
+const DefaultMongoClient = MongoClientService.Tag("@effect-mongodb/services/DefaultMongoClient")

packages/services/src/index.ts

@@ -1,3 +1,8 @@
+/**
+ * @since 0.0.1
+ */
+export * as DbInstance from "./DbInstance.js"
+
 /**
  * @since 0.0.1
  */