62 lines
2.4 KiB
Go
62 lines
2.4 KiB
Go
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// Copyright 2022 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//go:build go1.21
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package slog
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import (
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"log/slog"
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)
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// A Level is the importance or severity of a log event.
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// The higher the level, the more important or severe the event.
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type Level = slog.Level
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// Level numbers are inherently arbitrary,
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// but we picked them to satisfy three constraints.
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// Any system can map them to another numbering scheme if it wishes.
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//
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// First, we wanted the default level to be Info, Since Levels are ints, Info is
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// the default value for int, zero.
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//
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// Second, we wanted to make it easy to use levels to specify logger verbosity.
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// Since a larger level means a more severe event, a logger that accepts events
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// with smaller (or more negative) level means a more verbose logger. Logger
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// verbosity is thus the negation of event severity, and the default verbosity
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// of 0 accepts all events at least as severe as INFO.
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//
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// Third, we wanted some room between levels to accommodate schemes with named
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// levels between ours. For example, Google Cloud Logging defines a Notice level
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// between Info and Warn. Since there are only a few of these intermediate
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// levels, the gap between the numbers need not be large. Our gap of 4 matches
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// OpenTelemetry's mapping. Subtracting 9 from an OpenTelemetry level in the
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// DEBUG, INFO, WARN and ERROR ranges converts it to the corresponding slog
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// Level range. OpenTelemetry also has the names TRACE and FATAL, which slog
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// does not. But those OpenTelemetry levels can still be represented as slog
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// Levels by using the appropriate integers.
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//
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// Names for common levels.
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const (
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LevelDebug Level = slog.LevelDebug
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LevelInfo Level = slog.LevelInfo
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LevelWarn Level = slog.LevelWarn
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LevelError Level = slog.LevelError
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)
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// A LevelVar is a Level variable, to allow a Handler level to change
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// dynamically.
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// It implements Leveler as well as a Set method,
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// and it is safe for use by multiple goroutines.
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// The zero LevelVar corresponds to LevelInfo.
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type LevelVar = slog.LevelVar
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// A Leveler provides a Level value.
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//
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// As Level itself implements Leveler, clients typically supply
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// a Level value wherever a Leveler is needed, such as in HandlerOptions.
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// Clients who need to vary the level dynamically can provide a more complex
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// Leveler implementation such as *LevelVar.
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type Leveler = slog.Leveler
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