Convert to elasticsearch logging

.gitignore

@@ -1 +1 @@
-rsyslog_cron
+elastic_cron

README.md

@@ -21,6 +21,7 @@ This project is a quick and dirty replacement for running a cron daemon inside d
 ---
 
 elasticsearch:
+  index: 'elastic_cron-%{+YYYY.MM.dd}'
   servers:
     - http://localhost:9200
   auth: [username, password]
@@ -38,6 +39,7 @@ jobs:
 ```
 
 - `elasticsearch`
+  - `index` - Name of the index to write messages to (understands same date specifier as ES beats)
   - `servers` - List of elasticsearch instances of the same cluster to log to
   - `auth` - List consisting of two elements: username and password
 - `schedule` - consists of 6 instead of the normal 5 fields:

config.yml

@@ -1,6 +1,16 @@
 ---
-rsyslog_target: logs.myserver.com:12383
+
+elasticsearch:
+  index: 'elastic_cron-%{+YYYY.MM.dd}'
+  servers:
+    - http://localhost:9200
+  auth: [username, password]
+
 jobs:
   - name: date
     schedule: "0 * * * * *"
     cmd: "/bin/date"
+    args:
+      - "+%+"
+
+...

main.go

@@ -2,17 +2,20 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
-	"log"
 	"net/http"
 	"os"
 	"os/exec"
+	"regexp"
 	"strings"
 	"time"
 
 	"github.com/Luzifer/rconfig"
+	"github.com/elastic/beats/libbeat/common/dtfmt"
+	"github.com/olivere/elastic"
 	"github.com/robfig/cron"
+	log "github.com/sirupsen/logrus"
 	"golang.org/x/net/context"
+	elogrus "gopkg.in/sohlich/elogrus.v3"
 	"gopkg.in/yaml.v2"
 )
 
@@ -22,15 +25,17 @@ var (
 		Hostname   string        `flag:"hostname" description:"Overwrite system hostname"`
 		PingTimout time.Duration `flag:"ping-timeout" default:"1s" description:"Timeout for success / failure pings"`
 	}{}
-	version = "dev"
 
-	logstream = make(chan *message, 1000)
+	version = "dev"
 )
 
 type cronConfig struct {
-	RSyslogTarget string    `yaml:"rsyslog_target"`
-	LogTemplate   string    `yaml:"log_template"`
-	Jobs          []cronJob `yaml:"jobs"`
+	Elasticsearch struct {
+		Auth    []string `yaml:"auth"`
+		Index   string   `yaml:"index"`
+		Servers []string `yaml:"servers"`
+	} `yaml:"elasticsearch"`
+	Jobs []cronJob `yaml:"jobs"`
 }
 
 type cronJob struct {
@@ -43,7 +48,7 @@ type cronJob struct {
 }
 
 func init() {
-	rconfig.Parse(&cfg)
+	rconfig.ParseAndValidate(&cfg)
 
 	if cfg.Hostname == "" {
 		hostname, _ := os.Hostname()
@@ -51,19 +56,24 @@ func init() {
 	}
 }
 
+func readConfig() (*cronConfig, error) {
+	fp, err := os.Open(cfg.ConfigFile)
+	if err != nil {
+		return nil, err
+	}
+	defer fp.Close()
+
+	cc := &cronConfig{}
+	cc.Elasticsearch.Index = "elastic_cron-%{+YYYY.MM.dd}"
+	return cc, yaml.NewDecoder(fp).Decode(cc)
+}
+
 func main() {
-	body, err := ioutil.ReadFile(cfg.ConfigFile)
+	cc, err := readConfig()
 	if err != nil {
 		log.Fatalf("Unable to read config file: %s", err)
 	}
 
-	cc := cronConfig{
-		LogTemplate: `<{{ syslogpri .Severity }}>{{ .Date.Format "Jan 02 15:04:05" }} {{ .Hostname }} {{ .JobName }}: {{ .Message }}`,
-	}
-	if err := yaml.Unmarshal(body, &cc); err != nil {
-		log.Fatalf("Unable to parse config file: %s", err)
-	}
-
 	c := cron.New()
 
 	for i := range cc.Jobs {
@@ -73,28 +83,54 @@ func main() {
 		}
 	}
 
-	c.Start()
-
-	logadapter, err := NewSyslogAdapter(cc.RSyslogTarget, cc.LogTemplate)
-	if err != nil {
-		log.Fatalf("Unable to open syslog connection: %s", err)
+	opts := []elastic.ClientOptionFunc{
+		elastic.SetURL(cc.Elasticsearch.Servers...),
+	}
+
+	if cc.Elasticsearch.Auth != nil && len(cc.Elasticsearch.Auth) == 2 && cc.Elasticsearch.Auth[0] != "" {
+		opts = append(opts, elastic.SetBasicAuth(cc.Elasticsearch.Auth[0], cc.Elasticsearch.Auth[1]))
+	}
+
+	esClient, err := elastic.NewSimpleClient(opts...)
+	if err != nil {
+		log.WithError(err).Fatal("Unable to create elasticsearch client")
+	}
+
+	hook, err := elogrus.NewElasticHookWithFunc(esClient, cfg.Hostname, log.InfoLevel, getIndexNameFunc(cc))
+	if err != nil {
+		log.WithError(err).Fatal("Unable to create elasticsearch log hook")
+	}
+	log.AddHook(hook)
+
+	c.Run()
+}
+
+func getIndexNameFunc(cc *cronConfig) func() string {
+	if !strings.Contains(cc.Elasticsearch.Index, `%{+`) {
+		// Simple string without date expansion
+		return func() string { return cc.Elasticsearch.Index }
+	}
+
+	return func() string {
+		rex := regexp.MustCompile(`%{\+([^}]+)}`)
+		return rex.ReplaceAllStringFunc(cc.Elasticsearch.Index, func(f string) string {
+			f = strings.TrimSuffix(strings.TrimPrefix(f, `%{+`), `}`)
+			d, _ := dtfmt.Format(time.Now(), f)
+			return d
+		})
 	}
-	logadapter.Stream(logstream)
 }
 
 func getJobExecutor(job cronJob) func() {
 	return func() {
-		stdout := &messageChanWriter{
-			jobName:  job.Name,
-			msgChan:  logstream,
-			severity: 6, // Informational
-		}
+		logger := log.WithFields(log.Fields{
+			"job": job.Name,
+		})
 
-		stderr := &messageChanWriter{
-			jobName:  job.Name,
-			msgChan:  logstream,
-			severity: 3, // Error
-		}
+		stdout := logger.WriterLevel(log.InfoLevel)
+		defer stdout.Close()
+		stderr := logger.WriterLevel(log.ErrorLevel)
+		defer stderr.Close()
 
 		fmt.Fprintln(stdout, "[SYS] Starting job")
 
@@ -105,26 +141,26 @@ func getJobExecutor(job cronJob) func() {
 		err := cmd.Run()
 		switch err.(type) {
 		case nil:
-			fmt.Fprintln(stdout, "[SYS] Command execution successful")
+			logger.Info("[SYS] Command execution successful")
 			go func(url string) {
 				if err := doPing(url); err != nil {
-					fmt.Fprintf(stderr, "[SYS] Ping to URL %q caused an error: %s", url, err)
+					logger.WithError(err).Errorf("[SYS] Ping to URL %q caused an error", url)
 				}
 			}(job.PingSuccess)
 
 		case *exec.ExitError:
-			fmt.Fprintln(stderr, "[SYS] Command exited with unexpected exit code != 0")
+			logger.Info("[SYS] Command exited with unexpected exit code != 0")
 			go func(url string) {
 				if err := doPing(url); err != nil {
-					fmt.Fprintf(stderr, "[SYS] Ping to URL %q caused an error: %s", url, err)
+					logger.WithError(err).Errorf("[SYS] Ping to URL %q caused an error", url)
 				}
 			}(job.PingFailure)
 
 		default:
-			fmt.Fprintf(stderr, "[SYS] Execution caused error: %s\n", err)
+			logger.WithError(err).Error("[SYS] Execution caused error")
 			go func(url string) {
 				if err := doPing(url); err != nil {
-					fmt.Fprintf(stderr, "[SYS] Ping to URL %q caused an error: %s", url, err)
+					logger.WithError(err).Errorf("[SYS] Ping to URL %q caused an error", url)
 				}
 			}(job.PingFailure)
 
@@ -155,32 +191,3 @@ func doPing(url string) error {
 
 	return nil
 }
-
-type messageChanWriter struct {
-	jobName  string
-	msgChan  chan *message
-	severity int
-
-	buffer []byte
-}
-
-func (m *messageChanWriter) Write(p []byte) (n int, err error) {
-	n = len(p)
-	err = nil
-
-	m.buffer = append(m.buffer, p...)
-	if strings.Contains(string(m.buffer), "\n") {
-		lines := strings.Split(string(m.buffer), "\n")
-		for _, l := range lines[:len(lines)-1] {
-			m.msgChan <- &message{
-				Date:     time.Now(),
-				JobName:  m.jobName,
-				Message:  l,
-				Severity: m.severity,
-			}
-		}
-		m.buffer = []byte(lines[len(lines)-1])
-	}
-
-	return
-}