AsJSON returns a formatter that formats v as JSON.

Ctx constructs a Context from ctx with fn as its custom log function.

Discard is a Logf that throws away the logs given to it.

Filtered returns a Logf that silently swallows some log lines.

FromContext extracts a log function from ctx.

FuncWriter returns an io.Writer that writes to f.

LogfCloser wraps logf to create a logger that can be closed.

LogOnChange logs a given line only if line != lastLine, or if maxInterval has passed since the last time this identical line was logged.

RateLimitedFn is a wrapper for RateLimitedFnWithClock that includes the current time automatically.

RateLimitedFnWithClock returns a rate-limiting Logf wrapping the given logf.

RusagePrefixLog returns a Logf func wrapping the provided logf func that adds a prefixed log message to each line with the current binary memory usage and max RSS.

SlowLoggerWithClock is a logger that applies rate limits similar to RateLimitedFnWithClock, but instead of dropping logs will sleep until they can be written.

StdLogger returns a standard library logger from a Logf.

TestLogger returns a logger that logs to tb.Logf with a prefix to make it easier to distinguish spam from explicit test failures.

WithPrefix wraps f, prefixing each format with the provided prefix.

LogfKey stores and loads [Logf] values within a [context.Context].

HTTPServerLogFilter is an io.Writer that can be used as the net/http.Server.ErrorLog logger, and will filter out noisy, low-signal messages that clutter up logs.

TBLogger is the testing.TB subset needed by TestLogger.

ArgWriter is a fmt.Formatter that can be passed to any Logf func to efficiently write to a %v argument without allocations.

A Context is a context.Context that should contain a custom log function, obtainable from FromContext.

Logf is the basic Tailscale logger type: a printf-like func.