Documentation
¶
Overview ¶
Package logging constructs the *slog.Logger a process writes through, from a configuration that takes part in the layered load.
Configuration ¶
Config holds a Level and a Format and implements the config package's Merge and Finalize contract, so it loads as part of an application's configuration rather than on its own. Finalize composes its environment override names from the prefix it receives (via NewEnv, recorded on Env for introspection), normalizes (trims and lower-cases), applies defaults (info, text), reads the overrides, normalizes again, and validates. A value from a file or a shell therefore validates identically in any casing, and a blank or whitespace-only value takes the default. An empty prefix composes no names, disabling the overrides.
Level is a string. slog.Level parses it — "debug", "INFO", and offsets such as "warn+2", case-insensitively — through Level.Slog. An empty Level is unset, distinct from "set to info"; Finalize has replaced it with a default by the time validation runs.
Construction ¶
New returns a logger writing to the caller's io.Writer, with slog.NewJSONHandler selected by FormatJSON and slog.NewTextHandler otherwise. The caller supplies the writer; a test passes a buffer.
New returns no error; Finalize is the validation point. A Config literal that skipped Finalize yields an info-level logger.
Scope ¶
Subsystems take a *slog.Logger as an ordinary dependency. The HTTP request logger is in the web package.
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type Config ¶
Config selects the level and format the process logger is built with. Env records the environment-variable names Finalize composed and read; it is excluded from JSON.
type Env ¶
Env names the environment variables Config.Finalize reads. An empty name disables that one override; the zero value disables both.
func NewEnv ¶
NewEnv composes the standard override names from a prefix: LOG_LEVEL and LOG_FORMAT under whatever prefix config.EnvName produces.
type Level ¶
type Level string
Level is the minimum level the logger emits, in the vocabulary slog.Level parses: "debug", "INFO", and offsets such as "warn+2", case-insensitively. An empty Level is unset, distinct from "set to info".
const ( LevelDebug Level = "debug" LevelInfo Level = "info" LevelWarn Level = "warn" LevelError Level = "error" )
The standard levels; any string slog.Level parses is valid.
Source Files