Better logging (#6038) (#6095)

* Panic don't fatal on create new logger

Fixes #5854

Signed-off-by: Andrew Thornton <art27@cantab.net>

* partial broken

* Update the logging infrastrcture

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Reset the skip levels for Fatal and Error

Signed-off-by: Andrew Thornton <art27@cantab.net>

* broken ncsa

* More log.Error fixes

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Remove nal

* set log-levels to lowercase

* Make console_test test all levels

* switch to lowercased levels

* OK now working

* Fix vetting issues

* Fix lint

* Fix tests

* change default logging to match current gitea

* Improve log testing

Signed-off-by: Andrew Thornton <art27@cantab.net>

* reset error skip levels to 0

* Update documentation and access logger configuration

* Redirect the router log back to gitea if redirect macaron log but also allow setting the log level - i.e. TRACE

* Fix broken level caching

* Refactor the router log

* Add Router logger

* Add colorizing options

* Adjust router colors

* Only create logger if they will be used

* update app.ini.sample

* rename Attribute ColorAttribute

* Change from white to green for function

* Set fatal/error levels

* Restore initial trace logger

* Fix Trace arguments in modules/auth/auth.go

* Properly handle XORMLogger

* Improve admin/config page

* fix fmt

* Add auto-compression of old logs

* Update error log levels

* Remove the unnecessary skip argument from Error, Fatal and Critical

* Add stacktrace support

* Fix tests

* Remove x/sync from vendors?

* Add stderr option to console logger

* Use filepath.ToSlash to protect against Windows in tests

* Remove prefixed underscores from names in colors.go

* Remove not implemented database logger

This was removed from Gogs on 4 Mar 2016 but left in the configuration
since then.

* Ensure that log paths are relative to ROOT_PATH

* use path.Join

* rename jsonConfig to logConfig

* Rename "config" to "jsonConfig" to make it clearer

* Requested changes

* Requested changes: XormLogger

* Try to color the windows terminal

If successful default to colorizing the console logs

* fixup

* Colorize initially too

* update vendor

* Colorize logs on default and remove if this is not a colorizing logger

* Fix documentation

* fix test

* Use go-isatty to detect if on windows we are on msys or cygwin

* Fix spelling mistake

* Add missing vendors

* More changes

* Rationalise the ANSI writer protection

* Adjust colors on advice from @0x5c

* Make Flags a comma separated list

* Move to use the windows constant for ENABLE_VIRTUAL_TERMINAL_PROCESSING

* Ensure matching is done on the non-colored message - to simpify EXPRESSION

1 files changed, 83 insertions, 0 deletions

diff --git a/modules/log/stack.go b/modules/log/stack.go
new file mode 100644
index 0000000000..ffe9aa67cc
--- /dev/null
+++ b/modules/log/stack.go
@@ -0,0 +1,83 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package log
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"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 := ioutil.ReadFile(filename)
+			if err != nil {
+				// can't read this sourcefile
+				// 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.Replace(name, []byte("·"), []byte("."), -1)
+	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])
+}