import type * as Cause from "./Cause.ts";
import type * as Context from "./Context.ts";
import type * as Duration from "./Duration.ts";
import type * as Effect from "./Effect.ts";
import type * as Fiber from "./Fiber.ts";
import * as FileSystem from "./FileSystem.ts";
import * as Layer from "./Layer.ts";
import type * as LogLevel from "./LogLevel.ts";
import type { Pipeable } from "./Pipeable.ts";
import type { PlatformError } from "./PlatformError.ts";
import type * as Scope from "./Scope.ts";
declare const TypeId = "~effect/Logger";
/**
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 *
 * // Create a custom logger that accepts unknown messages and returns void
 * const stringLogger = Logger.make<unknown, void>((options) => {
 *   console.log(`[${options.logLevel}] ${options.message}`)
 * })
 *
 * // Create a logger that accepts any message type and returns a formatted string
 * const formattedLogger = Logger.make<unknown, string>((options) =>
 *   `${options.date.toISOString()} [${options.logLevel}] ${options.message}`
 * )
 *
 * // Use the logger in an Effect program
 * const program = Effect.log("Hello World").pipe(
 *   Effect.provide(Logger.layer([stringLogger]))
 * )
 * ```
 *
 * @since 2.0.0
 * @category models
 */
export interface Logger<in Message, out Output> extends Pipeable {
    readonly [TypeId]: typeof TypeId;
    log(options: Options<Message>): Output;
}
/**
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 *
 * // Options interface provides all logging context
 * const detailedLogger = Logger.make((options) => {
 *   const output = {
 *     message: options.message,
 *     level: options.logLevel,
 *     timestamp: options.date.toISOString(),
 *     fiberId: options.fiber.id,
 *     hasCause: options.cause !== undefined
 *   }
 *   console.log(JSON.stringify(output))
 * })
 *
 * const program = Effect.log("Processing request").pipe(
 *   Effect.provide(Logger.layer([detailedLogger]))
 * )
 * ```
 *
 * @since 2.0.0
 * @category models
 */
export interface Options<out Message> {
    readonly message: Message;
    readonly logLevel: LogLevel.LogLevel;
    readonly cause: Cause.Cause<unknown>;
    readonly fiber: Fiber.Fiber<unknown, unknown>;
    readonly date: Date;
}
/**
 * Returns `true` if the specified value is a `Logger`, otherwise returns `false`.
 *
 * @example
 * ```ts
 * import { Logger } from "effect"
 *
 * const myLogger = Logger.make((options) => {
 *   console.log(options.message)
 * })
 *
 * console.log(Logger.isLogger(myLogger)) // true
 * console.log(Logger.isLogger("not a logger")) // false
 * console.log(Logger.isLogger({ log: () => {} })) // false
 * ```
 *
 * @since 2.0.0
 * @category guards
 */
export declare const isLogger: (u: unknown) => u is Logger<unknown, unknown>;
/**
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 *
 * // Access current loggers from fiber context
 * const program = Effect.gen(function*() {
 *   const currentLoggers = yield* Effect.service(Logger.CurrentLoggers)
 *   console.log(`Number of active loggers: ${currentLoggers.size}`)
 *
 *   // Add a custom logger to the set
 *   const customLogger = Logger.make((options) => {
 *     console.log(`Custom: ${options.message}`)
 *   })
 *
 *   yield* Effect.log("Hello from custom logger").pipe(
 *     Effect.provide(Logger.layer([customLogger]))
 *   )
 * })
 * ```
 *
 * @since 4.0.0
 * @category references
 */
export declare const CurrentLoggers: Context.Reference<ReadonlySet<Logger<unknown, any>>>;
/**
 * @since 4.0.0
 * @category references
 */
export declare const LogToStderr: Context.Reference<boolean>;
/**
 * Transforms the output of a `Logger` using the provided function.
 *
 * This allows you to modify, enhance, or completely change the output format
 * of an existing logger without recreating the entire logging logic.
 *
 * @example
 * ```ts
 * import { Logger } from "effect"
 *
 * // Create a logger that outputs objects
 * const structuredLogger = Logger.make((options) => ({
 *   level: options.logLevel,
 *   message: options.message,
 *   timestamp: options.date.toISOString()
 * }))
 *
 * // Transform the output to JSON strings
 * const jsonStringLogger = Logger.map(
 *   structuredLogger,
 *   (output) => JSON.stringify(output)
 * )
 *
 * // Transform to uppercase messages
 * const uppercaseLogger = Logger.map(
 *   structuredLogger,
 *   (output) => ({ ...output, message: String(output.message).toUpperCase() })
 * )
 * ```
 *
 * @since 2.0.0
 * @category utils
 */
export declare const map: (<Output, Output2>(f: (output: Output) => Output2) => <Message>(self: Logger<Message, Output>) => Logger<Message, Output2>) & (<Message, Output, Output2>(self: Logger<Message, Output>, f: (output: Output) => Output2) => Logger<Message, Output2>);
/**
 * Returns a new `Logger` that writes all output of the specified `Logger` to
 * the console using `console.log`.
 *
 * This is useful for taking any logger that produces string or object output
 * and routing it to the console for development or debugging purposes.
 *
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 *
 * // Create a custom formatter
 * const customFormatter = Logger.make((options) =>
 *   `[${options.date.toISOString()}] ${options.logLevel}: ${options.message}`
 * )
 *
 * // Route to console
 * const consoleLogger = Logger.withConsoleLog(customFormatter)
 *
 * const program = Effect.log("Hello World").pipe(
 *   Effect.provide(Logger.layer([consoleLogger]))
 * )
 * ```
 *
 * @since 2.0.0
 * @category utils
 */
export declare const withConsoleLog: <Message, Output>(self: Logger<Message, Output>) => Logger<Message, void>;
/**
 * Returns a new `Logger` that writes all output of the specified `Logger` to
 * the console using `console.error`.
 *
 * This is particularly useful for error logging where you want to ensure
 * log messages appear in the error stream (stderr) rather than standard output.
 *
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 *
 * // Create an error-specific formatter
 * const errorFormatter = Logger.make((options) =>
 *   `ERROR [${options.date.toISOString()}]: ${options.message}`
 * )
 *
 * // Route to console.error
 * const errorLogger = Logger.withConsoleError(errorFormatter)
 *
 * const program = Effect.logError("Database connection failed").pipe(
 *   Effect.provide(Logger.layer([errorLogger]))
 * )
 * ```
 *
 * @since 2.0.0
 * @category utils
 */
export declare const withConsoleError: <Message, Output>(self: Logger<Message, Output>) => Logger<Message, void>;
/**
 * Returns a new `Logger` that writes all output of the specified `Logger` to
 * the console.
 *
 * Will use the appropriate console method (i.e. `console.log`, `console.error`,
 * etc.) based upon the current `LogLevel`.
 *
 * - `Debug` -> `console.debug`
 * - `Info` -> `console.info`
 * - `Trace` -> `console.trace`
 * - `Warn` -> `console.warn`
 * - `Error` and `Fatal` -> `console.error`
 * - Others -> `console.log`
 *
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 *
 * const formatter = Logger.make((options) =>
 *   `[${options.logLevel}] ${options.message}`
 * )
 *
 * const leveledLogger = Logger.withLeveledConsole(formatter)
 *
 * const program = Effect.gen(function*() {
 *   yield* Effect.logInfo("Info message") // -> console.info
 *   yield* Effect.logWarning("Warning") // -> console.warn
 *   yield* Effect.logError("Error occurred") // -> console.error
 *   yield* Effect.logDebug("Debug info") // -> console.debug
 * }).pipe(
 *   Effect.provide(Logger.layer([leveledLogger]))
 * )
 * ```
 *
 * @since 2.0.0
 * @category utils
 */
export declare const withLeveledConsole: <Message, Output>(self: Logger<Message, Output>) => Logger<Message, void>;
/**
 * Creates a new `Logger` from a log function.
 *
 * The log function receives an options object containing the message, log level,
 * cause, fiber information, and timestamp, and should return the desired output.
 *
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 * import { CurrentLogAnnotations } from "effect/References"
 *
 * // Simple text logger
 * const textLogger = Logger.make((options) =>
 *   `${options.date.toISOString()} [${options.logLevel}] ${options.message}`
 * )
 *
 * // Structured object logger
 * const objectLogger = Logger.make((options) => ({
 *   timestamp: options.date.toISOString(),
 *   level: options.logLevel,
 *   message: options.message,
 *   fiberId: options.fiber.id,
 *   annotations: options.fiber.getRef(CurrentLogAnnotations)
 * }))
 *
 * // Custom filtering logger
 * const filteredLogger = Logger.make((options) => {
 *   if (options.logLevel === "Debug") {
 *     return // Skip debug messages
 *   }
 *   return `${options.logLevel}: ${options.message}`
 * })
 *
 * const program = Effect.log("Hello World").pipe(
 *   Effect.provide(Logger.layer([textLogger]))
 * )
 * ```
 *
 * @since 2.0.0
 * @category constructors
 */
export declare const make: <Message, Output>(log: (options: Options<Message>) => Output) => Logger<Message, Output>;
/**
 * The default logging implementation used by the Effect runtime.
 *
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 *
 * // Use the default logger (automatically used by Effect runtime)
 * const program = Effect.gen(function*() {
 *   yield* Effect.log("This uses the default logger")
 *   yield* Effect.logInfo("Info message")
 *   yield* Effect.logError("Error message")
 * })
 *
 * // Explicitly use the default logger
 * const withDefaultLogger = Effect.log("Explicit default").pipe(
 *   Effect.provide(Logger.layer([Logger.defaultLogger]))
 * )
 *
 * // Compare with custom logger
 * const customLogger = Logger.make((options) => {
 *   console.log(`CUSTOM: ${options.message}`)
 * })
 * ```
 *
 * @since 4.0.0
 * @category constructors
 */
export declare const defaultLogger: Logger<unknown, void>;
/**
 * A `Logger` which outputs logs as a string.
 *
 * For example:
 * ```
 * timestamp=2025-01-03T14:22:47.570Z level=INFO fiber=#1 message=hello
 * ```
 *
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 *
 * // Use the simple format logger
 * const simpleLoggerProgram = Effect.log("Hello Simple Format").pipe(
 *   Effect.provide(Logger.layer([Logger.formatSimple]))
 * )
 *
 * // Combine with console output
 * const consoleSimpleLogger = Logger.withConsoleLog(Logger.formatSimple)
 *
 * const program = Effect.gen(function*() {
 *   yield* Effect.log("Application started")
 *   yield* Effect.logInfo("Processing data")
 *   yield* Effect.logWarning("Memory usage high")
 * }).pipe(
 *   Effect.provide(Logger.layer([consoleSimpleLogger]))
 * )
 * ```
 *
 * @since 4.0.0
 * @category constructors
 */
export declare const formatSimple: Logger<unknown, string>;
/**
 * A `Logger` which outputs logs using the [logfmt](https://brandur.org/logfmt)
 * style.
 *
 * For example:
 * ```
 * timestamp=2025-01-03T14:22:47.570Z level=INFO fiber=#1 message=hello
 * ```
 *
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 *
 * // Use the logfmt format logger
 * const logfmtLoggerProgram = Effect.log("Hello LogFmt Format").pipe(
 *   Effect.provide(Logger.layer([Logger.formatLogFmt]))
 * )
 *
 * // Perfect for structured logging systems
 * const structuredProgram = Effect.gen(function*() {
 *   yield* Effect.log("User login", { userId: 123, method: "OAuth" })
 *   yield* Effect.logInfo("Request processed", {
 *     duration: 45,
 *     status: "success"
 *   })
 * }).pipe(
 *   Effect.provide(Logger.layer([Logger.withConsoleLog(Logger.formatLogFmt)]))
 * )
 *
 * // Good for log aggregation systems like Splunk, ELK
 * const productionLogger = Logger.formatLogFmt
 * ```
 *
 * @since 4.0.0
 * @category constructors
 */
export declare const formatLogFmt: Logger<unknown, string>;
/**
 * A `Logger` which outputs logs using a structured format.
 *
 * For example:
 * ```
 * {
 *   message: [ 'hello' ],
 *   level: 'INFO',
 *   timestamp: '2025-01-03T14:25:39.666Z',
 *   annotations: { key: 'value' },
 *   spans: { label: 0 },
 *   fiberId: '#1'
 * }
 * ```
 *
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 *
 * // Use the structured format logger
 * const structuredLoggerProgram = Effect.log("Hello Structured Format").pipe(
 *   Effect.provide(Logger.layer([Logger.formatStructured]))
 * )
 *
 * // Perfect for JSON processing and analytics
 * const analyticsProgram = Effect.gen(function*() {
 *   yield* Effect.log("User action", { action: "click", element: "button" })
 *   yield* Effect.logInfo("API call", { endpoint: "/users", duration: 150 })
 * }).pipe(
 *   Effect.annotateLogs("sessionId", "abc123"),
 *   Effect.withLogSpan("request"),
 *   Effect.provide(Logger.layer([Logger.formatStructured]))
 * )
 *
 * // Process structured output
 * const processingLogger = Logger.map(Logger.formatStructured, (output) => {
 *   // Process the structured object
 *   const enhanced = { ...output, processed: true }
 *   return enhanced
 * })
 * ```
 *
 * @since 4.0.0
 * @category constructors
 */
export declare const formatStructured: Logger<unknown, {
    readonly level: string;
    readonly fiberId: string;
    readonly timestamp: string;
    readonly message: unknown;
    readonly cause: string | undefined;
    readonly annotations: Record<string, unknown>;
    readonly spans: Record<string, number>;
}>;
/**
 * A `Logger` which outputs logs using a structured format serialized as JSON
 * on a single line.
 *
 * For example:
 * ```
 * {"message":["hello"],"level":"INFO","timestamp":"2025-01-03T14:28:57.508Z","annotations":{"key":"value"},"spans":{"label":0},"fiberId":"#1"}
 * ```
 *
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 *
 * // Use the JSON format logger
 * const jsonLoggerProgram = Effect.log("Hello JSON Format").pipe(
 *   Effect.provide(Logger.layer([Logger.formatJson]))
 * )
 *
 * // Perfect for log aggregation and processing systems
 * const productionProgram = Effect.gen(function*() {
 *   yield* Effect.log("Server started", { port: 3000, env: "production" })
 *   yield* Effect.logInfo("Request received", {
 *     method: "GET",
 *     path: "/api/users"
 *   })
 *   yield* Effect.logError("Database error", { error: "Connection timeout" })
 * }).pipe(
 *   Effect.annotateLogs("service", "api-server"),
 *   Effect.withLogSpan("request-processing"),
 *   Effect.provide(Logger.layer([Logger.formatJson]))
 * )
 *
 * // Send to external logging service
 * const externalLogger = Logger.map(Logger.formatJson, (jsonString) => {
 *   // Send to Elasticsearch, CloudWatch, etc.
 *   console.log("Sending to external service:", jsonString)
 *   return jsonString
 * })
 * ```
 *
 * @since 4.0.0
 * @category constructors
 */
export declare const formatJson: Logger<unknown, string>;
/**
 * Returns a new `Logger` which will aggregate logs output by the specified
 * `Logger` over the provided `window`. After the `window` has elapsed, the
 * provided `flush` function will be called with the logs aggregated during
 * the last `window`.
 *
 * This is useful for implementing efficient batch processing of logs, such as
 * writing multiple log entries to a database or file in a single operation.
 *
 * @example
 * ```ts
 * import { Duration, Effect, Logger } from "effect"
 *
 * // Create a batched logger that flushes every 5 seconds
 * const batchedLogger = Logger.batched(Logger.formatJson, {
 *   window: Duration.seconds(5),
 *   flush: (messages) =>
 *     Effect.sync(() => {
 *       console.log(`Flushing ${messages.length} log entries:`)
 *       messages.forEach((msg, i) => console.log(`${i + 1}. ${msg}`))
 *     })
 * })
 *
 * const program = Effect.gen(function*() {
 *   const logger = yield* batchedLogger
 *
 *   yield* Effect.provide(
 *     Effect.all([
 *       Effect.log("Event 1"),
 *       Effect.log("Event 2"),
 *       Effect.log("Event 3"),
 *       Effect.sleep(Duration.seconds(6)), // Trigger flush
 *       Effect.log("Event 4")
 *     ]),
 *     Logger.layer([logger])
 *   )
 * })
 *
 * // Remote batch logging example
 * const remoteBatchLogger = Logger.batched(Logger.formatStructured, {
 *   window: Duration.seconds(10),
 *   flush: (entries) =>
 *     Effect.sync(() => {
 *       // Send batch to remote logging service
 *       console.log(`Sending ${entries.length} log entries to remote service`)
 *     })
 * })
 * ```
 *
 * @since 4.0.0
 * @category constructors
 */
export declare const batched: (<Output>(options: {
    readonly window: Duration.Input;
    readonly flush: (messages: Array<NoInfer<Output>>) => Effect.Effect<void>;
}) => <Message>(self: Logger<Message, Output>) => Effect.Effect<Logger<Message, void>, never, Scope.Scope>) & (<Message, Output>(self: Logger<Message, Output>, options: {
    readonly window: Duration.Input;
    readonly flush: (messages: Array<NoInfer<Output>>) => Effect.Effect<void>;
}) => Effect.Effect<Logger<Message, void>, never, Scope.Scope>);
/**
 * A `Logger` which outputs logs in a "pretty" format and writes them to the
 * console.
 *
 * For example:
 * ```
 * [09:37:17.579] INFO (#1) label=0ms: hello
 *   key: value
 * ```
 *
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 *
 * // Use the pretty console logger with default settings
 * const basicPretty = Effect.log("Hello Pretty Format").pipe(
 *   Effect.provide(Logger.layer([Logger.consolePretty()]))
 * )
 *
 * // Configure pretty logger options
 * const customPretty = Logger.consolePretty({
 *   colors: true,
 *   stderr: false,
 *   mode: "tty",
 *   formatDate: (date) => date.toLocaleTimeString()
 * })
 *
 * // Perfect for development environment
 * const developmentProgram = Effect.gen(function*() {
 *   yield* Effect.log("Application starting")
 *   yield* Effect.logInfo("Database connected")
 *   yield* Effect.logWarning("High memory usage detected")
 * }).pipe(
 *   Effect.annotateLogs("environment", "development"),
 *   Effect.withLogSpan("startup"),
 *   Effect.provide(Logger.layer([customPretty]))
 * )
 *
 * // Disable colors for CI/CD environments
 * const ciLogger = Logger.consolePretty({ colors: false })
 * ```
 *
 * @since 4.0.0
 * @category constructors
 */
export declare const consolePretty: (options?: {
    readonly colors?: "auto" | boolean | undefined;
    readonly stderr?: boolean | undefined;
    readonly formatDate?: ((date: Date) => string) | undefined;
    readonly mode?: "browser" | "tty" | "auto" | undefined;
}) => Logger<unknown, void>;
/**
 * A `Logger` which outputs logs using the [logfmt](https://brandur.org/logfmt)
 * style and writes them to the console.
 *
 * For example:
 * ```
 * timestamp=2025-01-03T14:22:47.570Z level=INFO fiber=#1 message=info
 * ```
 *
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 *
 * // Use the console logfmt logger
 * const logfmtProgram = Effect.log("Hello LogFmt Console").pipe(
 *   Effect.provide(Logger.layer([Logger.consoleLogFmt]))
 * )
 *
 * // Great for production environments
 * const productionProgram = Effect.gen(function*() {
 *   yield* Effect.log("Server started", { port: 8080, version: "1.0.0" })
 *   yield* Effect.logInfo("Request processed", { userId: 123, duration: 45 })
 *   yield* Effect.logError("Validation failed", {
 *     field: "email",
 *     value: "invalid"
 *   })
 * }).pipe(
 *   Effect.annotateLogs("service", "api"),
 *   Effect.withLogSpan("request-handler"),
 *   Effect.provide(Logger.layer([Logger.consoleLogFmt]))
 * )
 *
 * // Combine with other loggers
 * const multiLoggerLive = Logger.layer([
 *   Logger.consoleLogFmt,
 *   Logger.consolePretty()
 * ])
 * ```
 *
 * @since 2.0.0
 * @category constructors
 */
export declare const consoleLogFmt: Logger<unknown, void>;
/**
 * A `Logger` which outputs logs using a strctured format and writes them to
 * the console.
 *
 * For example:
 * ```
 * {
 *   message: [ 'info', 'message' ],
 *   level: 'INFO',
 *   timestamp: '2025-01-03T14:25:39.666Z',
 *   annotations: { key: 'value' },
 *   spans: { label: 0 },
 *   fiberId: '#1'
 * }
 * ```
 *
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 *
 * // Use the console structured logger
 * const structuredProgram = Effect.log("Hello Structured Console").pipe(
 *   Effect.provide(Logger.layer([Logger.consoleStructured]))
 * )
 *
 * // Perfect for development debugging
 * const debugProgram = Effect.gen(function*() {
 *   yield* Effect.log("User event", {
 *     userId: 123,
 *     action: "login",
 *     ip: "192.168.1.1"
 *   })
 *   yield* Effect.logInfo("API call", {
 *     endpoint: "/users",
 *     method: "GET",
 *     duration: 120
 *   })
 * }).pipe(
 *   Effect.annotateLogs("requestId", "req-123"),
 *   Effect.withLogSpan("authentication"),
 *   Effect.provide(Logger.layer([Logger.consoleStructured]))
 * )
 *
 * // Easy to parse and inspect object structure
 * const inspectionProgram = Effect.gen(function*() {
 *   yield* Effect.log("Complex data", {
 *     user: { id: 1, name: "John" },
 *     metadata: { source: "api", version: 2 }
 *   })
 * }).pipe(
 *   Effect.provide(Logger.layer([Logger.consoleStructured]))
 * )
 * ```
 *
 * @since 4.0.0
 * @category constructors
 */
export declare const consoleStructured: Logger<unknown, void>;
/**
 * A `Logger` which outputs logs using a structured format serialized as JSON
 * on a single line and writes them to the console.
 *
 * For example:
 * ```
 * {"message":["hello"],"level":"INFO","timestamp":"2025-01-03T14:28:57.508Z","annotations":{"key":"value"},"spans":{"label":0},"fiberId":"#1"}
 * ```
 *
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 *
 * // Use the console JSON logger
 * const jsonProgram = Effect.log("Hello JSON Console").pipe(
 *   Effect.provide(Logger.layer([Logger.consoleJson]))
 * )
 *
 * // Perfect for production logging and log aggregation
 * const productionProgram = Effect.gen(function*() {
 *   yield* Effect.log("Server started", { port: 3000, env: "production" })
 *   yield* Effect.logInfo("Request", {
 *     method: "POST",
 *     url: "/api/users",
 *     body: { name: "Alice" }
 *   })
 *   yield* Effect.logError("Database error", {
 *     error: "Connection timeout",
 *     retryCount: 3
 *   })
 * }).pipe(
 *   Effect.annotateLogs("service", "user-api"),
 *   Effect.annotateLogs("version", "1.2.3"),
 *   Effect.withLogSpan("request-processing"),
 *   Effect.provide(Logger.layer([Logger.consoleJson]))
 * )
 *
 * // Easy to pipe to log aggregation services
 * const productionSetup = Logger.layer([
 *   Logger.consoleJson, // For stdout JSON logs
 *   Logger.consolePretty() // For local debugging
 * ])
 *
 * // Ideal for containerized environments (Docker, Kubernetes)
 * const containerProgram = Effect.log("Container ready", {
 *   containerId: "abc123",
 *   image: "myapp:latest"
 * }).pipe(
 *   Effect.provide(Logger.layer([Logger.consoleJson]))
 * )
 * ```
 *
 * @since 4.0.0
 * @category constructors
 */
export declare const consoleJson: Logger<unknown, void>;
/**
 * A `Logger` which includes log messages as tracer span events.
 *
 * This logger integrates logging with distributed tracing by recording
 * all log messages as events on the current trace span, making them visible
 * in tracing tools like OpenTelemetry, Jaeger, or Zipkin.
 *
 * **Note**: This logger is included in the default set of loggers for all
 * Effect programs, so log messages automatically appear as span events unless
 * you override the default loggers.
 *
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 *
 * // Tracer logger is included by default - logs automatically become span events
 * const defaultProgram = Effect.gen(function*() {
 *   yield* Effect.log("This automatically becomes a span event")
 *   yield* Effect.logInfo("Processing data")
 * })
 *
 * // Explicitly combine tracer logger with other loggers
 * const observabilityProgram = Effect.gen(function*() {
 *   yield* Effect.log("Operation started")
 *   yield* Effect.logInfo("Processing data")
 *   yield* Effect.logError("Error occurred")
 * }).pipe(
 *   Effect.withLogSpan("data-processing"),
 *   Effect.provide(Logger.layer([
 *     Logger.tracerLogger,
 *     Logger.consoleJson
 *   ]))
 * )
 *
 * // Perfect for correlating logs with traces in distributed systems
 * const distributedProgram = Effect.gen(function*() {
 *   yield* Effect.log("Step 1: Fetching user data")
 *   yield* Effect.sleep("100 millis")
 *   yield* Effect.log("Step 2: Processing payment")
 *   yield* Effect.sleep("200 millis")
 *   yield* Effect.log("Step 3: Sending confirmation")
 * }).pipe(
 *   Effect.withLogSpan("payment-workflow"),
 *   Effect.annotateLogs("userId", "user-123"),
 *   Effect.provide(Logger.layer([Logger.tracerLogger]))
 * )
 * ```
 *
 * @since 4.0.0
 * @category constructors
 */
export declare const tracerLogger: Logger<unknown, void>;
/**
 * Creates a `Layer` which will overwrite the current set of loggers with the
 * specified array of `loggers`.
 *
 * If the specified array of `loggers` should be _merged_ with the current set
 * of loggers (instead of overwriting them), set `mergeWithExisting` to `true`.
 *
 * @example
 * ```ts
 * import { Effect, Logger } from "effect"
 *
 * // Single logger layer
 * const JsonLoggerLive = Logger.layer([Logger.consoleJson])
 *
 * // Multiple loggers layer
 * const MultiLoggerLive = Logger.layer([
 *   Logger.consoleJson,
 *   Logger.consolePretty(),
 *   Logger.formatStructured
 * ])
 *
 * // Merge with existing loggers
 * const AdditionalLoggerLive = Logger.layer(
 *   [Logger.consoleJson],
 *   { mergeWithExisting: true }
 * )
 *
 * // Using multiple logger formats
 * const jsonLogger = Logger.consoleJson
 * const prettyLogger = Logger.consolePretty()
 *
 * const CustomLoggerLive = Logger.layer([jsonLogger, prettyLogger])
 *
 * const program = Effect.log("Application started").pipe(
 *   Effect.provide(CustomLoggerLive)
 * )
 * ```
 *
 * @since 4.0.0
 * @category context
 */
export declare const layer: <const Loggers extends ReadonlyArray<Logger<unknown, unknown> | Effect.Effect<Logger<unknown, unknown>, any, any>>>(loggers: Loggers, options?: {
    readonly mergeWithExisting?: boolean | undefined;
} | undefined) => Layer.Layer<never, Loggers extends readonly [] ? never : Effect.Error<Loggers[number]>, Exclude<Loggers extends readonly [] ? never : Effect.Services<Loggers[number]>, Scope.Scope>>;
/**
 * Create a Logger from another string Logger that writes to the specified file.
 *
 * **Example**
 *
 * ```ts
 * import { NodeFileSystem, NodeRuntime } from "@effect/platform-node"
 * import { Effect, Layer, Logger } from "effect"
 *
 * const fileLogger = Logger.formatJson.pipe(
 *   Logger.toFile("/tmp/log.txt")
 * )
 * const LoggerLive = Logger.layer([fileLogger]).pipe(
 *   Layer.provide(NodeFileSystem.layer)
 * )
 *
 * Effect.log("a").pipe(
 *   Effect.andThen(Effect.log("b")),
 *   Effect.andThen(Effect.log("c")),
 *   Effect.provide(LoggerLive),
 *   NodeRuntime.runMain
 * )
 * ```
 *
 * @example
 * ```ts
 * import { NodeFileSystem } from "@effect/platform-node"
 * import { Duration, Effect, Logger } from "effect"
 *
 * // Basic file logging
 * const basicFileLogger = Effect.gen(function*() {
 *   const fileLogger = yield* Logger.formatJson.pipe(
 *     Logger.toFile("/tmp/app.log")
 *   )
 *
 *   yield* Effect.log("Application started").pipe(
 *     Effect.provide(Logger.layer([fileLogger]))
 *   )
 * }).pipe(
 *   Effect.provide(NodeFileSystem.layer)
 * )
 *
 * // File logger with custom batch window
 * const batchedFileLogger = Effect.gen(function*() {
 *   const fileLogger = yield* Logger.formatLogFmt.pipe(
 *     Logger.toFile("/var/log/myapp.log", {
 *       flag: "a",
 *       batchWindow: Duration.seconds(5)
 *     })
 *   )
 *
 *   yield* Effect.all([
 *     Effect.log("Event 1"),
 *     Effect.log("Event 2"),
 *     Effect.log("Event 3")
 *   ]).pipe(
 *     Effect.provide(Logger.layer([fileLogger]))
 *   )
 * }).pipe(
 *   Effect.provide(NodeFileSystem.layer)
 * )
 *
 * // Multiple loggers: console + file
 * const multiLogger = Effect.gen(function*() {
 *   const fileLogger = yield* Logger.formatJson.pipe(
 *     Logger.toFile("/tmp/production.log")
 *   )
 *
 *   const loggerLive = Logger.layer([
 *     Logger.consolePretty(),
 *     fileLogger
 *   ])
 *
 *   yield* Effect.log("Production event").pipe(
 *     Effect.provide(loggerLive)
 *   )
 * }).pipe(
 *   Effect.provide(NodeFileSystem.layer)
 * )
 * ```
 *
 * @since 4.0.0
 * @category file
 */
export declare const toFile: ((path: string, options?: {
    readonly flag?: FileSystem.OpenFlag | undefined;
    readonly mode?: number | undefined;
    readonly batchWindow?: Duration.Input | undefined;
} | undefined) => <Message>(self: Logger<Message, string>) => Effect.Effect<Logger<Message, void>, PlatformError, Scope.Scope | FileSystem.FileSystem>) & (<Message>(self: Logger<Message, string>, path: string, options?: {
    readonly flag?: FileSystem.OpenFlag | undefined;
    readonly mode?: number | undefined;
    readonly batchWindow?: Duration.Input | undefined;
} | undefined) => Effect.Effect<Logger<Message, void>, PlatformError, Scope.Scope | FileSystem.FileSystem>);
export {};
//# sourceMappingURL=Logger.d.ts.map