<Input, Output, EnvX, ErrorX, Error, Env>(
step: Effect<
(
options: InputMetadata<Input>
) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>,
Error,
Env
>
): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>Creates a Schedule from a step function that receives metadata about the schedule's execution.
Example (Creating a metadata-aware schedule)
import { Cause, Duration, Effect, Schedule } from "effect"
const firstThreeInputs = Schedule.fromStepWithMetadata(Effect.succeed((metadata: Schedule.InputMetadata<string>) => {
if (metadata.attempt > 3) {
return Cause.done("finished")
}
return Effect.succeed([
`attempt ${metadata.attempt}: ${metadata.input}`,
Duration.millis(250)
] as [string, Duration.Duration])
}))constructors
Source effect/Schedule.ts:33111 lines
export const const fromStepWithMetadata: <
Input,
Output,
EnvX,
ErrorX,
Error,
Env
>(
step: Effect<
(
options: InputMetadata<Input>
) => Pull.Pull<
[Output, Duration.Duration],
ErrorX,
Output,
EnvX
>,
Error,
Env
>
) => Schedule<
Output,
Input,
Error | Pull.ExcludeDone<ErrorX>,
Env | EnvX
>
Creates a Schedule from a step function that receives metadata about the schedule's execution.
Example (Creating a metadata-aware schedule)
import { Cause, Duration, Effect, Schedule } from "effect"
const firstThreeInputs = Schedule.fromStepWithMetadata(Effect.succeed((metadata: Schedule.InputMetadata<string>) => {
if (metadata.attempt > 3) {
return Cause.done("finished")
}
return Effect.succeed([
`attempt ${metadata.attempt}: ${metadata.input}`,
Duration.millis(250)
] as [string, Duration.Duration])
}))
fromStepWithMetadata = <function (type parameter) Input in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>Input, function (type parameter) Output in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>Output, function (type parameter) EnvX in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>EnvX, function (type parameter) ErrorX in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>ErrorX, function (type parameter) Error in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>Error, function (type parameter) Env in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>Env>(
step: Effect<
(
options: InputMetadata<Input>
) => Pull.Pull<
[Output, Duration.Duration],
ErrorX,
Output,
EnvX
>,
Error,
Env
>
(parameter) step: {
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
toString: () => string;
toJSON: () => unknown;
}
interface Effect<out A, out E = never, out R = never>The Effect interface defines a value that lazily describes a workflow or
job. The workflow requires some context R, and may fail with an error of
type E, or succeed with a value of type A.
When to use
Use when you need to represent a lazy, composable workflow that can require
services, fail with a typed error, or succeed with a typed value.
Details
Effect values model resourceful interaction with the outside world,
including synchronous, asynchronous, concurrent, and parallel interaction.
They use a fiber-based concurrency model, with built-in support for
scheduling, fine-grained interruption, structured concurrency, and high
scalability.
To run an Effect value, you need a Runtime, which is a type that is
capable of executing Effect values.
Effect<
(options: InputMetadata<Input>(parameter) options: {
input: Input;
attempt: number;
start: number;
now: number;
elapsed: number;
elapsedSincePrevious: number;
}
interface InputMetadata<Input>Metadata provided to schedule functions containing timing and input information.
InputMetadata<function (type parameter) Input in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>Input>) => import PullPull.interface Pull<out A, out E = never, out Done = void, out R = never>An effectful pull step that either produces a value, fails with E, or
signals completion with Cause.Done<Done>.
When to use
Use to model one low-level pull step when a consumer repeatedly evaluates an
effect that may emit a value, fail normally, or signal normal completion
through Cause.Done.
Details
Pull represents completion in the error channel so low-level stream
consumers can distinguish ordinary failures from end-of-input and carry a
leftover value when needed.
Pull<[function (type parameter) Output in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>Output, import DurationDuration.Duration], function (type parameter) ErrorX in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>ErrorX, function (type parameter) Output in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>Output, function (type parameter) EnvX in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>EnvX>,
function (type parameter) Error in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>Error,
function (type parameter) Env in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>Env
>
): interface Schedule<out Output, in Input = unknown, out Error = never, out Env = never>A Schedule defines a strategy for repeating or retrying effects based on some policy.
Example (Defining retry and repeat schedules)
import { Console, Data, Effect, Schedule } from "effect"
class NetworkError extends Data.TaggedError("NetworkError")<{
readonly attempt: number
}> {}
// Basic retry schedule - retry up to 3 times with exponential backoff
const retrySchedule = Schedule.max([
Schedule.exponential("100 millis"),
Schedule.recurs(3)
])
// Basic repeat schedule - repeat every 30 seconds forever
const repeatSchedule: Schedule.Schedule<number, unknown, never> = Schedule
.spaced("30 seconds")
const program = Effect.gen(function*() {
let attempts = 0
const result1 = yield* Effect.retry(
Effect.gen(function*() {
attempts++
if (attempts < 3) {
return yield* Effect.fail(new NetworkError({ attempt: attempts }))
}
return "Success"
}),
retrySchedule
)
console.log(result1) // "Success"
yield* Console.log("heartbeat").pipe(
Effect.repeat(repeatSchedule.pipe(Schedule.upTo({ times: 5 })))
)
})
The Schedule namespace contains types and utilities for working with schedules.
Schedule<function (type parameter) Output in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>Output, function (type parameter) Input in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>Input, function (type parameter) Error in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>Error | import PullPull.type ExcludeDone<E> =
E extends Cause.Done<any> ? never : E
Excludes Cause.Done completion signals from an error type union.
When to use
Use to describe the ordinary error type that remains after Cause.Done
completion signals have been handled or filtered out of an error union.
ExcludeDone<function (type parameter) ErrorX in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>ErrorX>, function (type parameter) Env in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>Env | function (type parameter) EnvX in <Input, Output, EnvX, ErrorX, Error, Env>(step: Effect<(options: InputMetadata<Input>) => Pull.Pull<[Output, Duration.Duration], ErrorX, Output, EnvX>, Error, Env>): Schedule<Output, Input, Error | Pull.ExcludeDone<ErrorX>, Env | EnvX>EnvX> =>
const fromStep: <
Input,
Output,
EnvX,
Error,
ErrorX,
Env
>(
step: Effect<
(
now: number,
input: Input
) => Pull.Pull<
[Output, Duration.Duration],
ErrorX,
Output,
EnvX
>,
Error,
Env
>
) => Schedule<
Output,
Input,
Error | Pull.ExcludeDone<ErrorX>,
Env | EnvX
>
Creates a Schedule from a step function that returns a Pull.
Example (Creating a custom schedule from a step function)
import { Cause, Duration, Effect, Schedule } from "effect"
const schedule = Schedule.fromStep(Effect.sync(() => {
let count = 0
return (_now: number, _input: string) => {
if (count >= 3) {
return Cause.done(count)
}
return Effect.succeed([count++, Duration.millis(100)] as [number, Duration.Duration])
}
}))
fromStep(import effecteffect.const map: {
<A, B>(f: (a: A) => B): <E, R>(
self: Effect.Effect<A, E, R>
) => Effect.Effect<B, E, R>
<A, E, R, B>(
self: Effect.Effect<A, E, R>,
f: (a: A) => B
): Effect.Effect<B, E, R>
}
step: Effect<
(
options: InputMetadata<Input>
) => Pull.Pull<
[Output, Duration.Duration],
ErrorX,
Output,
EnvX
>,
Error,
Env
>
(parameter) step: {
pipe: { <A>(this: A): A; <A, B = never>(this: A, ab: (_: A) => B): B; <A, B = never, C = never>(this: A, ab: (_: A) => B, bc: (_: B) => C): C; <A, B = never, C = never, D = never>(this: A, ab: (_: A) => B, bc: (_: B) => C, cd: (_: C) => D): D; <…;
toString: () => string;
toJSON: () => unknown;
}
f: (
options: InputMetadata<Input>
) => Pull.Pull<
[Output, Duration.Duration],
ErrorX,
Output,
EnvX
>
const meta: <In>(
now: number,
input: In
) => InputMetadata<In>
const metadataFn: () => <In>(
now: number,
input: In
) => InputMetadata<In>
now: numbernow, input: Inputinput) => f: (
options: InputMetadata<Input>
) => Pull.Pull<
[Output, Duration.Duration],
ErrorX,
Output,
EnvX
>
const meta: <In>(
now: number,
input: In
) => InputMetadata<In>
now: numbernow, input: Inputinput))
}))Referenced by 6 symbols