Add log-format option

README.md

@@ -94,5 +94,16 @@ When exclude users list or regex is set and no include option is set, `pgtermina
 
 LISTEN queries are asynchronous. Sessions are set to "idle" state even if they are waiting for messages to be sent to the queue. `pgterminate` can exclude sessions in that state by looking at the last known query starting with "LISTEN", with the `exclude-listeners` parameter.
 
+# Log format
+
+The following placeholders are available to format log messages using `log-format` option:
+* `%p`: pid
+* `%u`: username
+* `%d`: database name
+* `%r`: client (host:port)
+* `%s`: state
+* `%m`: state duration
+* `%q`: query
+
 # License
 `pgterminate` is released under [The Unlicense](LICENSE) license. Code is under public domain.

base/config.go

@@ -2,13 +2,14 @@ package base
 
 import (
 	"fmt"
-	"github.com/jouir/pgterminate/log"
-	"gopkg.in/yaml.v2"
 	"io/ioutil"
 	"path/filepath"
 	"regexp"
 	"strings"
 	"sync"
+
+	"github.com/jouir/pgterminate/log"
+	"gopkg.in/yaml.v2"
 )
 
 // AppName exposes application name to config module
@@ -29,6 +30,7 @@ type Config struct {
 	ActiveTimeout             float64     `yaml:"active-timeout"`
 	LogDestination            string      `yaml:"log-destination"`
 	LogFile                   string      `yaml:"log-file"`
+	LogFormat                 string      `yaml:"log-format"`
 	PidFile                   string      `yaml:"pid-file"`
 	SyslogIdent               string      `yaml:"syslog-ident"`
 	SyslogFacility            string      `yaml:"syslog-facility"`

base/session.go

@@ -29,31 +29,25 @@ func NewSession(pid int64, user string, db string, client string, state string,
 	}
 }
 
-// String represents a Session as a string
-func (s *Session) String() string {
-	var output []string
-	if s.Pid != 0 {
-		output = append(output, fmt.Sprintf("pid=%d", s.Pid))
+// Format returns a Session as a string by replacing placeholders with their respective value
+func (s *Session) Format(format string) string {
+	definitions := map[string]string{
+		"%p": fmt.Sprintf("%d", s.Pid),
+		"%u": s.User,
+		"%d": s.Db,
+		"%r": s.Client,
+		"%s": s.State,
+		"%m": fmt.Sprintf("%f", s.StateDuration),
+		"%q": s.Query,
 	}
-	if s.User != "" {
-		output = append(output, fmt.Sprintf("user=%s", s.User))
+
+	output := format
+
+	for placeholder, value := range definitions {
+		output = strings.Replace(output, placeholder, value, -1)
 	}
-	if s.Db != "" {
-		output = append(output, fmt.Sprintf("db=%s", s.Db))
-	}
-	if s.Client != "" {
-		output = append(output, fmt.Sprintf("client=%s", s.Client))
-	}
-	if s.State != "" {
-		output = append(output, fmt.Sprintf("state=%s", s.State))
-	}
-	if s.StateDuration != 0 {
-		output = append(output, fmt.Sprintf("state_duration=%f", s.StateDuration))
-	}
-	if s.Query != "" && !s.IsIdle() {
-		output = append(output, fmt.Sprintf("query=%s", s.Query))
-	}
-	return strings.Join(output, " ")
+
+	return output
 }
 
 // IsIdle returns true when a session is doing nothing

cmd/pgterminate/main.go

@@ -3,17 +3,18 @@ package main
 import (
 	"flag"
 	"fmt"
-	"github.com/jouir/pgterminate/base"
-	"github.com/jouir/pgterminate/log"
-	"github.com/jouir/pgterminate/notifier"
-	"github.com/jouir/pgterminate/terminator"
-	"golang.org/x/crypto/ssh/terminal"
 	"os"
 	"os/signal"
 	"regexp"
 	"strconv"
 	"sync"
 	"syscall"
+
+	"github.com/jouir/pgterminate/base"
+	"github.com/jouir/pgterminate/log"
+	"github.com/jouir/pgterminate/notifier"
+	"github.com/jouir/pgterminate/terminator"
+	"golang.org/x/crypto/ssh/terminal"
 )
 
 // AppVersion stores application version at compilation time
@@ -40,6 +41,7 @@ func main() {
 	flag.Float64Var(&config.ActiveTimeout, "active-timeout", 0, "Time for active connections to be terminated in seconds")
 	flag.StringVar(&config.LogDestination, "log-destination", "console", "Log destination between 'console', 'syslog' or 'file'")
 	flag.StringVar(&config.LogFile, "log-file", "", "Write logs to a file")
+	flag.StringVar(&config.LogFormat, "log-format", "pid=%p user=%u db=%d client=%r state=%s state_duration=%m query=%q", "Represent messages using this format")
 	flag.StringVar(&config.PidFile, "pid-file", "", "Write process id into a file")
 	flag.StringVar(&config.SyslogIdent, "syslog-ident", "pgterminate", "Define syslog tag")
 	flag.StringVar(&config.SyslogFacility, "syslog-facility", "", "Define syslog facility from LOCAL0 to LOCAL7")

config.yaml.example

@@ -8,6 +8,7 @@
 #idle-timeout: 300
 #active-timeout: 10
 #log-file: /var/log/pgterminate/pgterminate.log
+#log-format: 'pid=%p user=%u db=%d client=%r state=%s state_duration=%m query=%q'
 #pid-file: /var/run/pgterminate/pgterminate.pid
 #log-destination: console|file|syslog
 #syslog-ident: pgterminate
@@ -20,4 +21,4 @@
 #    user1
 #    user2
 #exclude-users-regex: "(user1|user2)"
-#cancel
+#cancel

notifier/console.go

@@ -7,12 +7,14 @@ import (
 
 // Console notifier structure
 type Console struct {
+	format   string
 	sessions chan *base.Session
 }
 
 // NewConsole creates a console notifier
-func NewConsole(sessions chan *base.Session) Notifier {
+func NewConsole(format string, sessions chan *base.Session) Notifier {
 	return &Console{
+		format:   format,
 		sessions: sessions,
 	}
 }
@@ -21,7 +23,7 @@ func NewConsole(sessions chan *base.Session) Notifier {
 func (c *Console) Run() {
 	log.Info("Starting console notifier")
 	for session := range c.sessions {
-		log.Infof("%s\n", session)
+		log.Info(session.Format(c.format))
 	}
 }
 

notifier/file.go

@@ -1,25 +1,28 @@
 package notifier
 
 import (
-	"github.com/jouir/pgterminate/base"
-	"github.com/jouir/pgterminate/log"
 	"os"
 	"sync"
 	"time"
+
+	"github.com/jouir/pgterminate/base"
+	"github.com/jouir/pgterminate/log"
 )
 
 // File structure for file notifier
 type File struct {
 	handle   *os.File
+	format   string
 	name     string
 	sessions chan *base.Session
 	mutex    sync.Mutex
 }
 
 // NewFile creates a file notifier
-func NewFile(name string, sessions chan *base.Session) Notifier {
+func NewFile(format string, name string, sessions chan *base.Session) Notifier {
 	return &File{
 		name:     name,
+		format:   format,
 		sessions: sessions,
 	}
 }
@@ -32,7 +35,7 @@ func (f *File) Run() {
 
 	for session := range f.sessions {
 		timestamp := time.Now().Format(time.RFC3339)
-		_, err := f.handle.WriteString(timestamp + " " + session.String() + "\n")
+		_, err := f.handle.WriteString(timestamp + " " + session.Format(f.format) + "\n")
 		base.Panic(err)
 	}
 }

notifier/notifier.go

@@ -15,10 +15,10 @@ type Notifier interface {
 func NewNotifier(ctx *base.Context) Notifier {
 	switch ctx.Config.LogDestination {
 	case "file":
-		return NewFile(ctx.Config.LogFile, ctx.Sessions)
+		return NewFile(ctx.Config.LogFile, ctx.Config.LogFormat, ctx.Sessions)
 	case "syslog":
-		return NewSyslog(ctx.Config.SyslogFacility, ctx.Config.SyslogIdent, ctx.Sessions)
+		return NewSyslog(ctx.Config.SyslogFacility, ctx.Config.SyslogIdent, ctx.Config.LogFormat, ctx.Sessions)
 	default: // console
-		return NewConsole(ctx.Sessions)
+		return NewConsole(ctx.Config.LogFormat, ctx.Sessions)
 	}
 }

notifier/syslog.go

@@ -1,22 +1,23 @@
 package notifier
 
 import (
-	"fmt"
+	"log/syslog"
+
 	"github.com/jouir/pgterminate/base"
 	"github.com/jouir/pgterminate/log"
-	"log/syslog"
 )
 
 // Syslog notifier
 type Syslog struct {
 	sessions chan *base.Session
 	ident    string
+	format   string
 	priority syslog.Priority
 	writer   *syslog.Writer
 }
 
 // NewSyslog creates a syslog notifier
-func NewSyslog(facility string, ident string, sessions chan *base.Session) Notifier {
+func NewSyslog(facility string, ident string, format string, sessions chan *base.Session) Notifier {
 	var priority syslog.Priority
 	switch facility {
 	case "LOCAL0":
@@ -40,6 +41,7 @@ func NewSyslog(facility string, ident string, sessions chan *base.Session) Notif
 		sessions: sessions,
 		ident:    ident,
 		priority: priority,
+		format:   format,
 	}
 }
 
@@ -51,7 +53,7 @@ func (s *Syslog) Run() {
 		base.Panic(err)
 	}
 	for session := range s.sessions {
-		s.writer.Info(fmt.Sprintf("%s", session))
+		s.writer.Info(session.Format(s.format))
 	}
 }