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forgejo/modules/log/stack.go
wxiaoguang 4647660776
Rewrite logger system ()
## ⚠️ Breaking

The `log.<mode>.<logger>` style config has been dropped. If you used it,
please check the new config manual & app.example.ini to make your
instance output logs as expected.

Although many legacy options still work, it's encouraged to upgrade to
the new options.

The SMTP logger is deleted because SMTP is not suitable to collect logs.

If you have manually configured Gitea log options, please confirm the
logger system works as expected after upgrading.

## Description

Close  and maybe more log-related issues, resolve some related
FIXMEs in old code (which seems unfixable before)

Just like rewriting queue  : make code maintainable, clear legacy
bugs, and add the ability to support more writers (eg: JSON, structured
log)

There is a new document (with examples): `logging-config.en-us.md`

This PR is safer than the queue rewriting, because it's just for
logging, it won't break other logic.

## The old problems

The logging system is quite old and difficult to maintain:
* Unclear concepts: Logger, NamedLogger, MultiChannelledLogger,
SubLogger, EventLogger, WriterLogger etc
* Some code is diffuclt to konw whether it is right:
`log.DelNamedLogger("console")` vs `log.DelNamedLogger(log.DEFAULT)` vs
`log.DelLogger("console")`
* The old system heavily depends on ini config system, it's difficult to
create new logger for different purpose, and it's very fragile.
* The "color" trick is difficult to use and read, many colors are
unnecessary, and in the future structured log could help
* It's difficult to add other log formats, eg: JSON format
* The log outputer doesn't have full control of its goroutine, it's
difficult to make outputer have advanced behaviors
* The logs could be lost in some cases: eg: no Fatal error when using
CLI.
* Config options are passed by JSON, which is quite fragile.
* INI package makes the KEY in `[log]` section visible in `[log.sub1]`
and `[log.sub1.subA]`, this behavior is quite fragile and would cause
more unclear problems, and there is no strong requirement to support
`log.<mode>.<logger>` syntax.


## The new design

See `logger.go` for documents.


## Screenshot

<details>


![image](https://github.com/go-gitea/gitea/assets/2114189/4462d713-ba39-41f5-bb08-de912e67e1ff)


![image](https://github.com/go-gitea/gitea/assets/2114189/b188035e-f691-428b-8b2d-ff7b2199b2f9)


![image](https://github.com/go-gitea/gitea/assets/2114189/132e9745-1c3b-4e00-9e0d-15eaea495dee)

</details>

## TODO

* [x] add some new tests
* [x] fix some tests
* [x] test some sub-commands (manually ....)

---------

Co-authored-by: Jason Song <i@wolfogre.com>
Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: Giteabot <teabot@gitea.io>
2023-05-21 22:35:11 +00:00

81 lines
2.5 KiB
Go

// Copyright 2019 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package log
import (
"bytes"
"fmt"
"os"
"runtime"
)
var unknown = []byte("???")
// Stack will skip back the provided number of frames and return a stack trace with source code.
// Although we could just use debug.Stack(), this routine will return the source code and
// skip back the provided number of frames - i.e. allowing us to ignore preceding function calls.
// A skip of 0 returns the stack trace for the calling function, not including this call.
// If the problem is a lack of memory of course all this is not going to work...
func Stack(skip int) string {
buf := new(bytes.Buffer)
// Store the last file we opened as its probable that the preceding stack frame
// will be in the same file
var lines [][]byte
var lastFilename string
for i := skip + 1; ; i++ { // Skip over frames
programCounter, filename, lineNumber, ok := runtime.Caller(i)
// If we can't retrieve the information break - basically we're into go internals at this point.
if !ok {
break
}
// Print equivalent of debug.Stack()
_, _ = fmt.Fprintf(buf, "%s:%d (0x%x)\n", filename, lineNumber, programCounter)
// Now try to print the offending line
if filename != lastFilename {
data, err := os.ReadFile(filename)
if err != nil {
// can't read this source file
// likely we don't have the sourcecode available
continue
}
lines = bytes.Split(data, []byte{'\n'})
lastFilename = filename
}
_, _ = fmt.Fprintf(buf, "\t%s: %s\n", functionName(programCounter), source(lines, lineNumber))
}
return buf.String()
}
// functionName converts the provided programCounter into a function name
func functionName(programCounter uintptr) []byte {
function := runtime.FuncForPC(programCounter)
if function == nil {
return unknown
}
name := []byte(function.Name())
// Because we provide the filename we can drop the preceding package name.
if lastslash := bytes.LastIndex(name, []byte("/")); lastslash >= 0 {
name = name[lastslash+1:]
}
// And the current package name.
if period := bytes.Index(name, []byte(".")); period >= 0 {
name = name[period+1:]
}
// And we should just replace the interpunct with a dot
name = bytes.ReplaceAll(name, []byte("·"), []byte("."))
return name
}
// source returns a space-trimmed slice of the n'th line.
func source(lines [][]byte, n int) []byte {
n-- // in stack trace, lines are 1-indexed but our array is 0-indexed
if n < 0 || n >= len(lines) {
return unknown
}
return bytes.TrimSpace(lines[n])
}