zrepl/zfs/zfscmd/zfscmd-logging-scraper/zfscmd_logging_scraper.go
Christian Schwarz 10a14a8c50 [#307] add package trace, integrate it with logging, and adopt it throughout zrepl
package trace:

- introduce the concept of tasks and spans, tracked as linked list within ctx
    - see package-level docs for an overview of the concepts
    - **main feature 1**: unique stack of task and span IDs
        - makes it easy to follow a series of log entries in concurrent code
    - **main feature 2**: ability to produce a chrome://tracing-compatible trace file
        - either via an env variable or a `zrepl pprof` subcommand
        - this is not a CPU profile, we already have go pprof for that
        - but it is very useful to visually inspect where the
          replication / snapshotter / pruner spends its time
          ( fixes #307 )

usage in package daemon/logging:

- goal: every log entry should have a trace field with the ID stack from package trace

- make `logging.GetLogger(ctx, Subsys)` the authoritative `logger.Logger` factory function
    - the context carries a linked list of injected fields which
      `logging.GetLogger` adds to the logger it returns
    - `logging.GetLogger` also uses package `trace` to get the
      task-and-span-stack and injects it into the returned logger's fields
2020-05-19 11:30:02 +02:00

130 lines
2.9 KiB
Go

package main
import (
"bufio"
"encoding/json"
"fmt"
"os"
"regexp"
"strings"
"time"
"github.com/go-logfmt/logfmt"
"github.com/pkg/errors"
"github.com/spf13/pflag"
"github.com/zrepl/zrepl/daemon/logging"
)
type RuntimeLine struct {
LogTime time.Time
Cmd string
TotalTime, Usertime, Systime time.Duration
Error string
}
var humanFormatterLineRE = regexp.MustCompile(`^(\[[^\]]+\]){2}\[zfs.cmd\]\[[^\]]+\]:\s+command\s+exited\s+(with|without)\s+error\s+(.+)`)
func parseSecs(s string) (time.Duration, error) {
d, err := time.ParseDuration(s + "s")
if err != nil {
return 0, errors.Wrapf(err, "parse duration %q", s)
}
return d, nil
}
func parseHumanFormatterNodate(line string) (l RuntimeLine, err error) {
m := humanFormatterLineRE.FindStringSubmatch(line)
if m == nil {
return l, errors.New("human formatter regex does not match")
}
d := logfmt.NewDecoder(strings.NewReader(m[3]))
for d.ScanRecord() {
for d.ScanKeyval() {
k := string(d.Key())
v := string(d.Value())
switch k {
case "cmd":
l.Cmd = v
case "total_time_s":
l.TotalTime, err = parseSecs(v)
case "usertime_s":
l.Usertime, err = parseSecs(v)
case "systemtime_s":
l.Systime, err = parseSecs(v)
case "err":
l.Error = v
case "invocation":
continue // pass
default:
return l, errors.Errorf("unknown key %q", k)
}
if err != nil {
return l, err
}
}
}
if d.Err() != nil {
return l, errors.Wrap(d.Err(), "decode key value pairs")
}
return l, nil
}
func parseLogLine(line string) (l RuntimeLine, err error) {
m := dateRegex.FindStringSubmatch(line)
if len(m) != 3 {
return l, errors.Errorf("invalid date regex match %v", m)
}
dateTrimmed := strings.TrimSpace(m[1])
date, err := time.Parse(dateFormat, dateTrimmed)
if err != nil {
panic(fmt.Sprintf("cannot parse date %q: %s", dateTrimmed, err))
}
logLine := m[2]
l, err = parseHumanFormatterNodate(strings.TrimSpace(logLine))
l.LogTime = date
return l, err
}
var verbose bool
var dateRegexArg string
var dateRegex = regexp.MustCompile(`^([^\[]+)(.*)`)
var dateFormat = logging.HumanFormatterDateFormat
func main() {
pflag.StringVarP(&dateRegexArg, "dateRE", "d", "", "date regex")
pflag.StringVar(&dateFormat, "dateFormat", logging.HumanFormatterDateFormat, "go date format")
pflag.BoolVarP(&verbose, "verbose", "v", false, "verbose")
pflag.Parse()
if dateRegexArg != "" {
dateRegex = regexp.MustCompile(dateRegexArg)
}
input := bufio.NewScanner(os.Stdin)
input.Split(bufio.ScanLines)
enc := json.NewEncoder(os.Stdout)
for input.Scan() {
l, err := parseLogLine(input.Text())
if err != nil && verbose {
fmt.Fprintf(os.Stderr, "ignoring line after error %v\n", err)
fmt.Fprintf(os.Stderr, "offending line was: %s\n", input.Text())
}
if err == nil {
if err := enc.Encode(l); err != nil {
panic(err)
}
}
}
if input.Err() != nil {
panic(input.Err())
}
}