v2: Logging! (#2831)

* logging: Initial implementation

* logging: More encoder formats, better defaults

* logging: Fix repetition bug with FilterEncoder; add more presets

* logging: DiscardWriter; delete or no-op logs that discard their output

* logging: Add http.handlers.log module; enhance Replacer methods

The Replacer interface has new methods to customize how to handle empty
or unrecognized placeholders. Closes #2815.

* logging: Overhaul HTTP logging, fix bugs, improve filtering, etc.

* logging: General cleanup, begin transitioning to using new loggers

* Fixes after merge conflict

cmd/caddy/main.go

@@ -40,6 +40,7 @@ import (
 	_ "github.com/caddyserver/caddy/v2/modules/caddytls"
 	_ "github.com/caddyserver/caddy/v2/modules/caddytls/standardstek"
 	_ "github.com/caddyserver/caddy/v2/modules/filestorage"
+	_ "github.com/caddyserver/caddy/v2/modules/logging"
 )
 
 func main() {

cmd/commandfuncs.go

@@ -387,7 +387,7 @@ func cmdAdaptConfig(fl Flags) (int, error) {
 		if warn.Directive != "" {
 			msg = fmt.Sprintf("%s: %s", warn.Directive, warn.Message)
 		}
-		log.Printf("[WARNING][%s] %s:%d: %s", adaptCmdAdapterFlag, warn.File, warn.Line, msg)
+		fmt.Fprintf(os.Stderr, "[WARNING][%s] %s:%d: %s\n", adaptCmdAdapterFlag, warn.File, warn.Line, msg)
 	}
 
 	// print result to stdout
@@ -436,7 +436,7 @@ func cmdValidateConfig(fl Flags) (int, error) {
 			if warn.Directive != "" {
 				msg = fmt.Sprintf("%s: %s", warn.Directive, warn.Message)
 			}
-			log.Printf("[WARNING][%s] %s:%d: %s", validateCmdAdapterFlag, warn.File, warn.Line, msg)
+			fmt.Fprintf(os.Stderr, "[WARNING][%s] %s:%d: %s\n", validateCmdAdapterFlag, warn.File, warn.Line, msg)
 		}
 
 		input = adaptedConfig

cmd/commands.go

@@ -130,9 +130,9 @@ not quit after printing, and can be useful for troubleshooting.`,
 	RegisterCommand(Command{
 		Name:  "stop",
 		Func:  cmdStop,
-		Short: "Gracefully stops the running Caddy process",
+		Short: "Gracefully stops a started Caddy process",
 		Long: `
-Stops the running Caddy process as gracefully as possible.
+Stops the background Caddy process as gracefully as possible.
 
 On Windows, this stop is forceful and Caddy will not have an opportunity to
 clean up any active locks; for a graceful shutdown on Windows, use Ctrl+C

cmd/main.go

@@ -20,7 +20,6 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
-	"log"
 	"net"
 	"os"
 	"strconv"
@@ -38,7 +37,7 @@ func Main() {
 
 	switch len(os.Args) {
 	case 0:
-		log.Printf("[FATAL] no arguments provided by OS; args[0] must be command")
+		fmt.Printf("[FATAL] no arguments provided by OS; args[0] must be command\n")
 		os.Exit(caddy.ExitCodeFailedStartup)
 	case 1:
 		os.Args = append(os.Args, "help")
@@ -49,9 +48,9 @@ func Main() {
 	if !ok {
 		if strings.HasPrefix(os.Args[1], "-") {
 			// user probably forgot to type the subcommand
-			log.Println("[ERROR] first argument must be a subcommand; see 'caddy help'")
+			fmt.Println("[ERROR] first argument must be a subcommand; see 'caddy help'")
 		} else {
-			log.Printf("[ERROR] '%s' is not a recognized subcommand; see 'caddy help'", os.Args[1])
+			fmt.Printf("[ERROR] '%s' is not a recognized subcommand; see 'caddy help'\n", os.Args[1])
 		}
 		os.Exit(caddy.ExitCodeFailedStartup)
 	}
@@ -63,13 +62,13 @@ func Main() {
 
 	err := fs.Parse(os.Args[2:])
 	if err != nil {
-		log.Println(err)
+		fmt.Println(err)
 		os.Exit(caddy.ExitCodeFailedStartup)
 	}
 
 	exitCode, err := subcommand.Func(Flags{fs})
 	if err != nil {
-		log.Printf("%s: %v", subcommand.Name, err)
+		fmt.Printf("%s: %v\n", subcommand.Name, err)
 	}
 
 	os.Exit(exitCode)
@@ -149,7 +148,7 @@ func loadConfig(configFile, adapterName string) ([]byte, error) {
 			if warn.Directive != "" {
 				msg = fmt.Sprintf("%s: %s", warn.Directive, warn.Message)
 			}
-			fmt.Printf("[WARNING][%s] %s:%d: %s", adapterName, warn.File, warn.Line, msg)
+			fmt.Printf("[WARNING][%s] %s:%d: %s\n", adapterName, warn.File, warn.Line, msg)
 		}
 		config = adaptedConfig
 	}

cmd/proc_posix.go

@@ -24,7 +24,7 @@ import (
 )
 
 func gracefullyStopProcess(pid int) error {
-	fmt.Printf("Graceful stop...")
+	fmt.Printf("Graceful stop...\n")
 	err := syscall.Kill(pid, syscall.SIGINT)
 	if err != nil {
 		return fmt.Errorf("kill: %v", err)

cmd/proc_windows.go

@@ -23,7 +23,7 @@ import (
 )
 
 func gracefullyStopProcess(pid int) error {
-	fmt.Printf("Forceful Stop...")
+	fmt.Printf("Forceful Stop...\n")
 	// process on windows will not stop unless forced with /f
 	cmd := exec.Command("taskkill", "/pid", strconv.Itoa(pid), "/f")
 	if err := cmd.Run(); err != nil {