Documentation
¶
Overview ¶
Package fmtlog adds Sprintf-style log messages as a LogLayer plugin. Register it once and every call site that passes a format string followed by arguments gets fmt.Sprintf semantics:
log.AddPlugin(fmtlog.New())
log.Info("user %d signed in", userID)
log.WithMetadata(loglayer.Metadata{"reqId": id}).
Error("request %s failed: %v", id, err)
Without the plugin, multi-argument calls are space-joined (`fmt.Sprintf("%v", arg)` per element). Registering New opts the logger into format-string semantics: any call where the first message is a string and there are extra arguments is rewritten to fmt.Sprintf(messages[0], messages[1:]...) before downstream MessageHooks run.
See https://go.loglayer.dev for usage guides and the full API reference.
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func New ¶
func New() loglayer.Plugin
New returns a plugin that resolves multi-argument log messages via fmt.Sprintf. The plugin is a single MessageHook: zero hot-path cost when a call has only one message; one Sprintf when there are extras.
Example ¶
New returns a plugin that rewrites multi-argument log messages via fmt.Sprintf when the first message is a format string. Single-message calls are untouched.
tr := lltesting.New(lltesting.Config{})
log := loglayer.New(loglayer.Config{
Transport: tr,
DisableFatalExit: true,
Plugins: []loglayer.Plugin{fmtlog.New()},
})
log.Info("user %d signed in", 42)
line := tr.Library.PopLine()
fmt.Println(line.Messages[0])
Output: user 42 signed in
Types ¶
This section is empty.
Source Files