log: implement a glog style pattern matching handler
This commit is contained in:
Péter Szilágyi
parent
3f923f3902
commit
47af53f9aa
227
log/handler_glog.go
Normal file
227
log/handler_glog.go
Normal file
@ -0,0 +1,227 @@
|
|||||||
|
// Copyright 2017 The go-ethereum Authors
|
||||||
|
// This file is part of the go-ethereum library.
|
||||||
|
//
|
||||||
|
// The go-ethereum library is free software: you can redistribute it and/or modify
|
||||||
|
// it under the terms of the GNU Lesser General Public License as published by
|
||||||
|
// the Free Software Foundation, either version 3 of the License, or
|
||||||
|
// (at your option) any later version.
|
||||||
|
//
|
||||||
|
// The go-ethereum library is distributed in the hope that it will be useful,
|
||||||
|
// but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||||
|
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||||||
|
// GNU Lesser General Public License for more details.
|
||||||
|
//
|
||||||
|
// You should have received a copy of the GNU Lesser General Public License
|
||||||
|
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
|
||||||
|
|
||||||
|
package log
|
||||||
|
|
||||||
|
import (
|
||||||
|
"errors"
|
||||||
|
"fmt"
|
||||||
|
"regexp"
|
||||||
|
"runtime"
|
||||||
|
"strconv"
|
||||||
|
"strings"
|
||||||
|
"sync"
|
||||||
|
"sync/atomic"
|
||||||
|
)
|
||||||
|
|
||||||
|
// errVmoduleSyntax is returned when a user vmodule pattern is invalid.
|
||||||
|
var errVmoduleSyntax = errors.New("expect comma-separated list of filename=N")
|
||||||
|
|
||||||
|
// errTraceSyntax is returned when a user backtrace pattern is invalid.
|
||||||
|
var errTraceSyntax = errors.New("expect file.go:234")
|
||||||
|
|
||||||
|
// GlogHandler is a log handler that mimics the filtering features of Google's
|
||||||
|
// glog logger: setting global log levels; overriding with callsite pattern
|
||||||
|
// matches; and requesting backtraces at certain positions.
|
||||||
|
type GlogHandler struct {
|
||||||
|
origin Handler // The origin handler this wraps
|
||||||
|
|
||||||
|
level uint32 // Current log level, atomically accessible
|
||||||
|
override uint32 // Flag whether overrides are used, atomically accessible
|
||||||
|
backtrace uint32 // Flag whether backtrace location is set
|
||||||
|
|
||||||
|
patterns []pattern // Current list of patterns to override with
|
||||||
|
siteCache map[uintptr]Lvl // Cache of callsite pattern evaluations
|
||||||
|
location string // file:line location where to do a stackdump at
|
||||||
|
lock sync.RWMutex // Lock protecting the override pattern list
|
||||||
|
}
|
||||||
|
|
||||||
|
// NewGlogHandler creates a new log handler with filtering functionality similar
|
||||||
|
// to Google's glog logger. The returned handler implements Handler.
|
||||||
|
func NewGlogHandler(h Handler) *GlogHandler {
|
||||||
|
return &GlogHandler{
|
||||||
|
origin: h,
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
// pattern contains a filter for the Vmodule option, holding a verbosity level
|
||||||
|
// and a file pattern to match.
|
||||||
|
type pattern struct {
|
||||||
|
pattern *regexp.Regexp
|
||||||
|
level Lvl
|
||||||
|
}
|
||||||
|
|
||||||
|
// Verbosity sets the glog verbosity ceiling. The verbosity of individual packages
|
||||||
|
// and source files can be raised using Vmodule.
|
||||||
|
func (h *GlogHandler) Verbosity(level Lvl) {
|
||||||
|
atomic.StoreUint32(&h.level, uint32(level))
|
||||||
|
}
|
||||||
|
|
||||||
|
// Vmodule sets the glog verbosity pattern.
|
||||||
|
//
|
||||||
|
// The syntax of the argument is a comma-separated list of pattern=N, where the
|
||||||
|
// pattern is a literal file name or "glob" pattern matching and N is a V level.
|
||||||
|
//
|
||||||
|
// For instance:
|
||||||
|
//
|
||||||
|
// pattern="gopher.go=3"
|
||||||
|
// sets the V level to 3 in all Go files named "gopher.go"
|
||||||
|
//
|
||||||
|
// pattern="foo=3"
|
||||||
|
// sets V to 3 in all files of any packages whose import path ends in "foo"
|
||||||
|
//
|
||||||
|
// pattern="foo/*=3"
|
||||||
|
// sets V to 3 in all files of any packages whose import path contains "foo"
|
||||||
|
func (h *GlogHandler) Vmodule(ruleset string) error {
|
||||||
|
var filter []pattern
|
||||||
|
for _, rule := range strings.Split(ruleset, ",") {
|
||||||
|
// Empty strings such as from a trailing comma can be ignored
|
||||||
|
if len(rule) == 0 {
|
||||||
|
continue
|
||||||
|
}
|
||||||
|
// Ensure we have a pattern = level filter rule
|
||||||
|
parts := strings.Split(rule, "=")
|
||||||
|
if len(parts) != 2 {
|
||||||
|
return errVmoduleSyntax
|
||||||
|
}
|
||||||
|
parts[0] = strings.TrimSpace(parts[0])
|
||||||
|
parts[1] = strings.TrimSpace(parts[1])
|
||||||
|
if len(parts[0]) == 0 || len(parts[1]) == 0 {
|
||||||
|
return errVmoduleSyntax
|
||||||
|
}
|
||||||
|
// Parse the level and if correct, assemble the filter rule
|
||||||
|
level, err := strconv.Atoi(parts[1])
|
||||||
|
if err != nil {
|
||||||
|
return errVmoduleSyntax
|
||||||
|
}
|
||||||
|
if level <= 0 {
|
||||||
|
continue // Ignore. It's harmless but no point in paying the overhead.
|
||||||
|
}
|
||||||
|
// Compile the rule pattern into a regular expression
|
||||||
|
matcher := ".*"
|
||||||
|
for _, comp := range strings.Split(parts[0], "/") {
|
||||||
|
if comp == "*" {
|
||||||
|
matcher += "(/.*)?"
|
||||||
|
} else if comp != "" {
|
||||||
|
matcher += "/" + regexp.QuoteMeta(comp)
|
||||||
|
}
|
||||||
|
}
|
||||||
|
if !strings.HasSuffix(parts[0], ".go") {
|
||||||
|
matcher += "/[^/]+\\.go"
|
||||||
|
}
|
||||||
|
matcher = matcher + "$"
|
||||||
|
|
||||||
|
re, _ := regexp.Compile(matcher)
|
||||||
|
filter = append(filter, pattern{re, Lvl(level)})
|
||||||
|
}
|
||||||
|
// Swap out the vmodule pattern for the new filter system
|
||||||
|
h.lock.Lock()
|
||||||
|
defer h.lock.Unlock()
|
||||||
|
|
||||||
|
h.patterns = filter
|
||||||
|
h.siteCache = make(map[uintptr]Lvl)
|
||||||
|
atomic.StoreUint32(&h.override, uint32(len(filter)))
|
||||||
|
|
||||||
|
return nil
|
||||||
|
}
|
||||||
|
|
||||||
|
// BacktraceAt sets the glog backtrace location. When set to a file and line
|
||||||
|
// number holding a logging statement, a stack trace will be written to the Info
|
||||||
|
// log whenever execution hits that statement.
|
||||||
|
//
|
||||||
|
// Unlike with Vmodule, the ".go" must be present.
|
||||||
|
func (h *GlogHandler) BacktraceAt(location string) error {
|
||||||
|
// Ensure the backtrace location contains two non-empty elements
|
||||||
|
parts := strings.Split(location, ":")
|
||||||
|
if len(parts) != 2 {
|
||||||
|
return errTraceSyntax
|
||||||
|
}
|
||||||
|
parts[0] = strings.TrimSpace(parts[0])
|
||||||
|
parts[1] = strings.TrimSpace(parts[1])
|
||||||
|
if len(parts[0]) == 0 || len(parts[1]) == 0 {
|
||||||
|
return errTraceSyntax
|
||||||
|
}
|
||||||
|
// Ensure the .go prefix is present and the line is valid
|
||||||
|
if !strings.HasSuffix(parts[0], ".go") {
|
||||||
|
return errTraceSyntax
|
||||||
|
}
|
||||||
|
if _, err := strconv.Atoi(parts[1]); err != nil {
|
||||||
|
return errTraceSyntax
|
||||||
|
}
|
||||||
|
// All seems valid
|
||||||
|
h.lock.Lock()
|
||||||
|
defer h.lock.Unlock()
|
||||||
|
|
||||||
|
h.location = location
|
||||||
|
atomic.StoreUint32(&h.backtrace, uint32(len(location)))
|
||||||
|
|
||||||
|
return nil
|
||||||
|
}
|
||||||
|
|
||||||
|
// Log implements Handler.Log, filtering a log record through the global, local
|
||||||
|
// and backtrace filters, finally emitting it if either allow it through.
|
||||||
|
func (h *GlogHandler) Log(r *Record) error {
|
||||||
|
// If backtracing is requested, check whether this is the callsite
|
||||||
|
if atomic.LoadUint32(&h.backtrace) > 0 {
|
||||||
|
// Everything below here is slow. Although we could cache the call sites the
|
||||||
|
// same way as for vmodule, backtracing is so rare it's not worth the extra
|
||||||
|
// complexity.
|
||||||
|
h.lock.RLock()
|
||||||
|
match := h.location == r.Call.String()
|
||||||
|
h.lock.RUnlock()
|
||||||
|
|
||||||
|
if match {
|
||||||
|
// Callsite matched, raise the log level to info and gather the stacks
|
||||||
|
r.Lvl = LvlInfo
|
||||||
|
|
||||||
|
buf := make([]byte, 1024*1024)
|
||||||
|
buf = buf[:runtime.Stack(buf, true)]
|
||||||
|
r.Msg += "\n\n" + string(buf)
|
||||||
|
}
|
||||||
|
}
|
||||||
|
// If the global log level allows, fast track logging
|
||||||
|
if atomic.LoadUint32(&h.level) >= uint32(r.Lvl) {
|
||||||
|
return h.origin.Log(r)
|
||||||
|
}
|
||||||
|
// If no local overrides are present, fast track skipping
|
||||||
|
if atomic.LoadUint32(&h.override) == 0 {
|
||||||
|
return nil
|
||||||
|
}
|
||||||
|
// Check callsite cache for previously calculated log levels
|
||||||
|
h.lock.RLock()
|
||||||
|
lvl, ok := h.siteCache[r.Call.PC()]
|
||||||
|
h.lock.RUnlock()
|
||||||
|
|
||||||
|
// If we didn't cache the callsite yet, calculate it
|
||||||
|
if !ok {
|
||||||
|
h.lock.Lock()
|
||||||
|
for _, rule := range h.patterns {
|
||||||
|
if rule.pattern.MatchString(fmt.Sprintf("%+s", r.Call)) {
|
||||||
|
h.siteCache[r.Call.PC()], lvl, ok = rule.level, rule.level, true
|
||||||
|
break
|
||||||
|
}
|
||||||
|
}
|
||||||
|
// If no rule matched, remember to drop log the next time
|
||||||
|
if !ok {
|
||||||
|
h.siteCache[r.Call.PC()] = 0
|
||||||
|
}
|
||||||
|
h.lock.Unlock()
|
||||||
|
}
|
||||||
|
if lvl >= r.Lvl {
|
||||||
|
return h.origin.Log(r)
|
||||||
|
}
|
||||||
|
return nil
|
||||||
|
}
|
||||||
Loading…
Reference in New Issue
Block a user