FLog: Naive Fixed Log in Golang

• A strongly-opinionated key-value stylish log library, zero-configuration (un-configurable)
• 这是一个带有强烈个人观点的简单日志库, KV风格，零配置（不可配置）

Usage 用法

• import "flog/log"，not import "flog"

import "flog/log"

log.Debug().Int("key", -42).IntPad0("code", 0, 8).UintPad0("value", 321, 4).Msg("Hello World!")
log.Info().Str("host", "example.com").Uint("port", 9527).Msg("Hello World!")
log.Warn().Hex("raw", 0x42ab).Hex("neg", -2).Msgf("Greeting %s!", "World")

// shorthand
log.Infof("Hello %s!", "World!") // same as `log.Info().Msgf(...)`

• must call finishing methods (i.e. Msg/Msgf) to actually print the log
• supported types (hope one day Go type-parameterized method works, revise them as several generic functions):
  • Bool, Str
  • Int, Int8, Int16, Int32, Int64 (waiting for Int[T ~Int|~Int8|...](k string, v T))
  • Uint, Uint8, Uint16, Uint32, Uint64
  • Float32, Float64
  • Err
  • Any

Why 为什么

• Most configurations are fixed in daily work (at least in the same company we intented to unify log configurations): log format, time format and other things
• 日常工作中，日志的绝大部分配置是固定、统一的（一个开发团队中至少应该统一日志格式及其使用方式）：比如日志格式、日期格式等
• zap is too complicated/free, and zerolog is json-intimated
• zap配置太复杂/灵活，而zerolog简单但是以json为主
• use fixed/hardcoded logic may be helpful for performance
• 使用固定/硬编码的逻辑，可能会有更好的性能

I need feature XXX 我需要xxx功能

• copy to codebase, e.g. under pkg/flog & modify by yourself 😏
• 自己动手，丰衣足食，把flog模块放到自己的工程里去，比如pkg/flog，然后修改就完了

Philosophy 哲学

• 12factor on logs

  should not attempt to write to or manage logfiles. Instead, each running process writes its event stream, unbuffered, to stdout

• 12factor关于日志部分

  不应该试图去写或者管理日志文件。相反，每一个运行的进程不用缓冲，直接写事件流到标准输出（stdout）

• In most scenarios, app is running as a systemctl service or docker container, which has alread take care of our logs, managing logs by app itself is redundant.
• 在绝大多数场景下，app作为一个systemctl的服务或者docker容器运行，外部环境/服务已经管理好我们的日志了（通过重定向标准输出），自己管理日志通常是多此一举
• If you really want to write log files and rotate, better to do it by other tools through pipe, which meets The UNIX Philosophy e.g.
• 如果你需要将日志写到文件中并滚动起来，更好的办法是写一个专门的应用，并通过管道去使用，这也符合UNIX哲学，比如：

  $ my_app | tee logToFiles -d /var/logs/my_app/ --rotate-size 1m --files-keep 5
  $ other_app | tee sendToKafka -c config.yml

How 如何实现

• copy(dst , src []byte)
• cache time for print only seconds/milliseconds part
• reduce/eliminate memory allocations
• reuse buffer: pre-allocated buffer & sync.Pool
• replace printf("%d", int) with efficient integer to string conversions, by Matthew Wilson, and refer strconv.Append...

TODO

• support Map to print all KV directly?
• Hex for negative values: Printf("%#08x", -0xbad) == "-0x00bad"