<Resource, E, R, A, E2, R2, E3, R3>(
acquire: Effect<Resource, E, R>,
use: (a: Resource) => Effect<A, E2, R2>,
release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>
): Effect<A, E | E2 | E3, R | R2 | R3>Runs resource acquisition, usage, and release as one bracketed effect.
When to use
Use to bracket acquire, use, and release logic in one effect.
Details
acquireUseRelease does the following:
- Ensures that the
Effectvalue that acquires the resource will not be interrupted. Note that acquisition may still fail due to internal reasons (such as an uncaught exception). - Ensures that the
releaseEffectvalue will not be interrupted, and will be executed as long as the acquisitionEffectvalue successfully acquires the resource.
During the time period between the acquisition and release of the resource,
the use Effect value will be executed.
If the release Effect value fails, then the entire Effect value will
fail, even if the use Effect value succeeds. If this fail-fast behavior
is not desired, errors produced by the release Effect value can be caught
and ignored.
Example (Acquiring resources with cleanup)
import { Console, Effect, Exit } from "effect"
interface Database {
readonly connection: string
readonly query: (sql: string) => Effect.Effect<string>
}
const program = Effect.acquireUseRelease(
// Acquire - connect to database
Effect.gen(function*() {
yield* Console.log("Connecting to database...")
return {
connection: "db://localhost:5432",
query: (sql: string) => Effect.succeed(`Result for: ${sql}`)
}
}),
// Use - perform database operations
(db) =>
Effect.gen(function*() {
yield* Console.log(`Connected to ${db.connection}`)
const result = yield* db.query("SELECT * FROM users")
yield* Console.log(`Query result: ${result}`)
return result
}),
// Release - close database connection
(db, exit) =>
Effect.gen(function*() {
if (Exit.isSuccess(exit)) {
yield* Console.log(`Closing connection to ${db.connection} (success)`)
} else {
yield* Console.log(`Closing connection to ${db.connection} (failure)`)
}
})
)
Effect.runPromise(program)
// Output:
// Connecting to database...
// Connected to db://localhost:5432
// Query result: Result for: SELECT * FROM users
// Closing connection to db://localhost:5432 (success)export const const acquireUseRelease: <
Resource,
E,
R,
A,
E2,
R2,
E3,
R3
>(
acquire: Effect<Resource, E, R>,
use: (a: Resource) => Effect<A, E2, R2>,
release: (
a: Resource,
exit: Exit.Exit<A, E2>
) => Effect<void, E3, R3>
) => Effect<A, E | E2 | E3, R | R2 | R3>
Runs resource acquisition, usage, and release as one bracketed effect.
When to use
Use to bracket acquire, use, and release logic in one effect.
Details
acquireUseRelease does the following:
- Ensures that the
Effect value that acquires the resource will not be
interrupted. Note that acquisition may still fail due to internal
reasons (such as an uncaught exception).
- Ensures that the
release Effect value will not be interrupted,
and will be executed as long as the acquisition Effect value
successfully acquires the resource.
During the time period between the acquisition and release of the resource,
the use Effect value will be executed.
If the release Effect value fails, then the entire Effect value will
fail, even if the use Effect value succeeds. If this fail-fast behavior
is not desired, errors produced by the release Effect value can be caught
and ignored.
Example (Acquiring resources with cleanup)
import { Console, Effect, Exit } from "effect"
interface Database {
readonly connection: string
readonly query: (sql: string) => Effect.Effect<string>
}
const program = Effect.acquireUseRelease(
// Acquire - connect to database
Effect.gen(function*() {
yield* Console.log("Connecting to database...")
return {
connection: "db://localhost:5432",
query: (sql: string) => Effect.succeed(`Result for: ${sql}`)
}
}),
// Use - perform database operations
(db) =>
Effect.gen(function*() {
yield* Console.log(`Connected to ${db.connection}`)
const result = yield* db.query("SELECT * FROM users")
yield* Console.log(`Query result: ${result}`)
return result
}),
// Release - close database connection
(db, exit) =>
Effect.gen(function*() {
if (Exit.isSuccess(exit)) {
yield* Console.log(`Closing connection to ${db.connection} (success)`)
} else {
yield* Console.log(`Closing connection to ${db.connection} (failure)`)
}
})
)
Effect.runPromise(program)
// Output:
// Connecting to database...
// Connected to db://localhost:5432
// Query result: Result for: SELECT * FROM users
// Closing connection to db://localhost:5432 (success)
acquireUseRelease: <function (type parameter) Resource in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>Resource, function (type parameter) E in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>E, function (type parameter) R in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>R, function (type parameter) A in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>A, function (type parameter) E2 in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>E2, function (type parameter) R2 in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>R2, function (type parameter) E3 in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>E3, function (type parameter) R3 in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>R3>(
acquire: Effect<Resource, E, R>(parameter) acquire: {
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<function (type parameter) Resource in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>Resource, function (type parameter) E in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>E, function (type parameter) R in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>R>,
use: (a: Resource) => Effect<A, E2, R2>use: (a: Resourcea: function (type parameter) Resource in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>Resource) => 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<function (type parameter) A in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>A, function (type parameter) E2 in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>E2, function (type parameter) R2 in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>R2>,
release: (
a: Resource,
exit: Exit.Exit<A, E2>
) => Effect<void, E3, R3>
a: Resourcea: function (type parameter) Resource in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>Resource, exit: Exit.Exit<A, E2>exit: import ExitExit.type Exit<A, E = never> = Exit.Success<A, E> | Exit.Failure<A, E>Represents the result of an Effect computation.
When to use
Use when you need to synchronously inspect whether an Effect computation
succeeded or failed.
Details
An Exit<A, E> is either Success<A, E> containing a value of type A, or
Failure<A, E> containing a Cause<E> describing why the computation
failed.
Since Exit is also an Effect, you can yield it inside Effect.gen.
Example (Pattern matching on an Exit)
import { Exit } from "effect"
const success: Exit.Exit<number> = Exit.succeed(42)
const failure: Exit.Exit<number, string> = Exit.fail("error")
const result = Exit.match(success, {
onSuccess: (value) => `Got value: ${value}`,
onFailure: (cause) => `Got error: ${cause}`
})
Namespace containing helper types shared by Exit values.
When to use
Use to reference helper types that describe the shared structure of Exit
values.
Exit<function (type parameter) A in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>A, function (type parameter) E2 in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>E2>) => 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<void, function (type parameter) E3 in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>E3, function (type parameter) R3 in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>R3>
) => 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<function (type parameter) A in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>A, function (type parameter) E in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>E | function (type parameter) E2 in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>E2 | function (type parameter) E3 in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>E3, function (type parameter) R in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>R | function (type parameter) R2 in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>R2 | function (type parameter) R3 in <Resource, E, R, A, E2, R2, E3, R3>(acquire: Effect<Resource, E, R>, use: (a: Resource) => Effect<A, E2, R2>, release: (a: Resource, exit: Exit.Exit<A, E2>) => Effect<void, E3, R3>): Effect<A, E | E2 | E3, R | R2 | R3>R3> = import internalinternal.const acquireUseRelease: <
Resource,
E,
R,
A,
E2,
R2,
E3,
R3
>(
acquire: Effect.Effect<Resource, E, R>,
use: (a: Resource) => Effect.Effect<A, E2, R2>,
release: (
a: Resource,
exit: Exit.Exit<A, E2>
) => Effect.Effect<void, E3, R3>
) => Effect.Effect<A, E | E2 | E3, R | R2 | R3>