Ensuring Closure of DB Client in Program Workflow
Hey all 
I have a program that needs to write to a DB.
The DB client is passed as a layer.
How can I ensure that the client is closed when the workflow finish?
I looked into resource management, but it's not clear to me how to use it with layers
I have a program that needs to write to a DB.
The DB client is passed as a layer.
How can I ensure that the client is closed when the workflow finish?
I looked into resource management, but it's not clear to me how to use it with layers
interface AwesomeDbClient {
write: (key: string, value: string) => Promise<void>
close: () => Promise<void>
}
type DBArgs = S.To<typeof DBArgs>
const DBArgs = S.struct({
host: S.string,
})
export const DBClient = Context.Tag<AwesomeDbClient>()
export const makeDbClient = (args: DBArgs) => {
const client = {
write: (key: string, value: any) => {
console.log(`writing ${key} ${value} to ${args.host}`)
return Promise.resolve()
},
close: () => {
console.log(`closing connection to ${args.host}`)
return Promise.resolve()
}
}
// client.connect()
return Effect.succeed(client)
}
const clientLive = makeDbClient({ host: 'localhost' })
const writeToDb = (client: AwesomeDbClient, key: string, data: any) => {
client.write(key, data)
}
const program = DBClient.pipe(
Effect.flatMap((client) =>
Effect.tryPromise(async () => {
return writeToDb(client, "foo", { bar: 'data' })
}),
),
Effect.provideLayer(Layer.effect(DBClient, clientLive))
)
Effect.runPromise(program).then(() => console.log('done'))interface AwesomeDbClient {
write: (key: string, value: string) => Promise<void>
close: () => Promise<void>
}
type DBArgs = S.To<typeof DBArgs>
const DBArgs = S.struct({
host: S.string,
})
export const DBClient = Context.Tag<AwesomeDbClient>()
export const makeDbClient = (args: DBArgs) => {
const client = {
write: (key: string, value: any) => {
console.log(`writing ${key} ${value} to ${args.host}`)
return Promise.resolve()
},
close: () => {
console.log(`closing connection to ${args.host}`)
return Promise.resolve()
}
}
// client.connect()
return Effect.succeed(client)
}
const clientLive = makeDbClient({ host: 'localhost' })
const writeToDb = (client: AwesomeDbClient, key: string, data: any) => {
client.write(key, data)
}
const program = DBClient.pipe(
Effect.flatMap((client) =>
Effect.tryPromise(async () => {
return writeToDb(client, "foo", { bar: 'data' })
}),
),
Effect.provideLayer(Layer.effect(DBClient, clientLive))
)
Effect.runPromise(program).then(() => console.log('done'))
