Context.Reference<LogLevel>Context reference for controlling the current trace level for dynamic filtering.
When to use
Use to set the default trace level for spans in a scope when span options do
not provide level.
Details
The default value is "Info". Span creation uses options.level ??
CurrentTraceLevel before applying MinimumTraceLevel.
export const const CurrentTraceLevel: Context.Reference<LogLevel>const CurrentTraceLevel: {
defaultValue: () => Shape;
of: (this: void, self: LogLevel) => LogLevel;
context: (self: LogLevel) => Context.Context<never>;
use: (f: (service: LogLevel) => Effect<A, E, R>) => Effect<A, E, R>;
useSync: (f: (service: LogLevel) => A) => Effect<A, never, never>;
Identifier: Identifier;
Service: Shape;
key: string;
stack: string | undefined;
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;
}
Context reference for controlling the current trace level for dynamic filtering.
When to use
Use to set the default trace level for spans in a scope when span options do
not provide level.
Details
The default value is "Info". Span creation uses options.level ??
CurrentTraceLevel before applying MinimumTraceLevel.
CurrentTraceLevel: import ContextContext.interface Reference<in out Shape>Service key with a lazily computed default value.
Details
When a Reference is requested from a Context that does not contain an
override, Context getters that resolve references return the cached default
value instead of failing.
Example (Defining a reference with a default value)
import { Context } from "effect"
// Define a reference with a default value
const LoggerRef: Context.Reference<{ log: (msg: string) => void }> =
Context.Reference("Logger", {
defaultValue: () => ({ log: (msg: string) => console.log(msg) })
})
// The reference can be used without explicit provision
const context = Context.empty()
const logger = Context.get(context, LoggerRef) // Uses default value
Creates a context key with a default value.
When to use
Use when you need to define a context key with a lazily computed default
value.
Details
Context.Reference allows you to create a key that can hold a value. You
can provide a default value for the service, which will automatically be used
when the context is accessed, or override it with a custom implementation
when needed. The default value is computed lazily and cached on the
reference.
Example (Creating references with default values)
import { Context } from "effect"
// Create a reference with a default value
const LoggerRef = Context.Reference("Logger", {
defaultValue: () => ({ log: (msg: string) => console.log(msg) })
})
// The reference provides the default value when accessed from an empty context
const context = Context.empty()
const logger = Context.get(context, LoggerRef)
// You can also override the default value
const customContext = Context.make(LoggerRef, {
log: (msg: string) => `Custom: ${msg}`
})
const customLogger = Context.get(customContext, LoggerRef)
Reference<type LogLevel = "All" | "Fatal" | "Error" | "Warn" | "Info" | "Debug" | "Trace" | "None"Represents every level used by Effect logging, including concrete message
severities and the All and None sentinel levels.
When to use
Use to type values that may be either concrete log message severities or
logging configuration sentinels.
Details
The levels are ordered from most severe to least severe:
All - Special level that allows all messagesFatal - System is unusable, immediate attention requiredError - Error conditions that should be investigatedWarn - Warning conditions that may indicate problemsInfo - Informational messages about normal operationDebug - Debug information useful during developmentTrace - Very detailed trace informationNone - Special level that suppresses all messages
Example (Using log levels)
import { Effect } from "effect"
// Using log levels with Effect logging
const program = Effect.gen(function*() {
yield* Effect.logFatal("System failure")
yield* Effect.logError("Database error")
yield* Effect.logWarning("High memory usage")
yield* Effect.logInfo("User logged in")
yield* Effect.logDebug("Processing request")
yield* Effect.logTrace("Variable state")
})
// Type-safe log level variables
const errorLevel = "Error" // LogLevel
const debugLevel = "Debug" // LogLevel
LogLevel> = import ContextContext.const Reference: <Service>(
key: string,
options: {
readonly defaultValue: () => Service
}
) => Reference<Service>
Creates a context key with a default value.
When to use
Use when you need to define a context key with a lazily computed default
value.
Details
Context.Reference allows you to create a key that can hold a value. You
can provide a default value for the service, which will automatically be used
when the context is accessed, or override it with a custom implementation
when needed. The default value is computed lazily and cached on the
reference.
Example (Creating references with default values)
import { Context } from "effect"
// Create a reference with a default value
const LoggerRef = Context.Reference("Logger", {
defaultValue: () => ({ log: (msg: string) => console.log(msg) })
})
// The reference provides the default value when accessed from an empty context
const context = Context.empty()
const logger = Context.get(context, LoggerRef)
// You can also override the default value
const customContext = Context.make(LoggerRef, {
log: (msg: string) => `Custom: ${msg}`
})
const customLogger = Context.get(customContext, LoggerRef)
Reference<type LogLevel = "All" | "Fatal" | "Error" | "Warn" | "Info" | "Debug" | "Trace" | "None"Represents every level used by Effect logging, including concrete message
severities and the All and None sentinel levels.
When to use
Use to type values that may be either concrete log message severities or
logging configuration sentinels.
Details
The levels are ordered from most severe to least severe:
All - Special level that allows all messagesFatal - System is unusable, immediate attention requiredError - Error conditions that should be investigatedWarn - Warning conditions that may indicate problemsInfo - Informational messages about normal operationDebug - Debug information useful during developmentTrace - Very detailed trace informationNone - Special level that suppresses all messages
Example (Using log levels)
import { Effect } from "effect"
// Using log levels with Effect logging
const program = Effect.gen(function*() {
yield* Effect.logFatal("System failure")
yield* Effect.logError("Database error")
yield* Effect.logWarning("High memory usage")
yield* Effect.logInfo("User logged in")
yield* Effect.logDebug("Processing request")
yield* Effect.logTrace("Variable state")
})
// Type-safe log level variables
const errorLevel = "Error" // LogLevel
const debugLevel = "Debug" // LogLevel
LogLevel>(
"effect/Tracer/CurrentTraceLevel",
{ defaultValue: () => LogLeveldefaultValue: () => "Info" }
)