cli: rework audit log trace and add error log trace

This commit does two things:
 - Add error log tracing via the `/v1/log/error/trace` API
 - Rework the audit log tracing CLI UI.

Now, the log event stream to STDOUT is displayed as a table:
```
┌──────────┬─────────────┬─────────────┬─────────────────────────────────────────┬──────────┐
│   Time   │  Identity   │   Status    │ API Operations                          │ Response │
├──────────┼─────────────┼─────────────┼─────────────────────────────────────────┼──────────┤
│ 13:43:48 │ 3ecfcdf38f… │   200 OK    │ /v1/log/audit/trace                     │  282µs   │
│ 15:08:06 │ 3ecfcdf38f… │   200 OK    │ /v1/key/generate/my-minio-key           │  550µs   │
└──────────┴─────────────┴─────────────┴─────────────────────────────────────────┴──────────┘
```

A user can specify whether the error or the audit log should be traced
via the `--type=[audit|error]` flag. The default is `--type=audit` which
is aligned with the previous behavior.

If a user wants to trace error and audit logs at the same time (e.g.
with `--json` flag) the following bash/zsh command can be used:
```
{ kes log trace --type=error --json & kes log trace --type=audit --json; } | jq
```

The current table CLI output requires that the terminal supports unicode
characters - which is the case for modern terminals, including windows.

cmd/kes/log.go

@@ -7,14 +7,18 @@ package main
 import (
 	"flag"
 	"fmt"
+	"io"
 	"net/http"
 	"os"
 	"os/signal"
-	"runtime"
-	"syscall"
+	"strings"
 	"time"
 
 	"github.com/fatih/color"
+	"github.com/minio/kes"
+	"github.com/minio/kes/internal/xterm"
+
+	ui "github.com/gizak/termui/v3"
 )
 
 const logCmdUsage = `usage: %s <command>
@@ -52,6 +56,11 @@ Connects to a KES server and traces log events.
 
 usage: %s [flags]
 
+  --type               Specify the log event type. (default: audit)
+                       Valid options are:
+                          --type=audit  
+                          --type=error
+
   --json               Print log events as JSON.
 
   -k, --insecure       Skip X.509 certificate validation during TLS handshake.
@@ -65,8 +74,13 @@ func logTrace(args []string) error {
 		fmt.Fprintf(cli.Output(), logTraceCmdUsage, cli.Name())
 	}
 
-	var jsonOutput bool
-	var insecureSkipVerify bool
+	var (
+		typeFlag   string
+		jsonOutput bool
+
+		insecureSkipVerify bool
+	)
+	cli.StringVar(&typeFlag, "type", "audit", "Log event type [ audit | error ]")
 	cli.BoolVar(&jsonOutput, "json", false, "Print log events as JSON")
 	cli.BoolVar(&insecureSkipVerify, "k", false, "Skip X.509 certificate validation during TLS handshake")
 	cli.BoolVar(&insecureSkipVerify, "insecure", false, "Skip X.509 certificate validation during TLS handshake")
@@ -79,60 +93,200 @@ func logTrace(args []string) error {
 	if err != nil {
 		return err
 	}
-	stream, err := client.TraceAuditLog()
-	if err != nil {
+
+	switch strings.ToLower(typeFlag) {
+	case "audit":
+		stream, err := client.TraceAuditLog()
+		if err != nil {
+			return err
+		}
+		defer stream.Close()
+
+		if !isTerm(os.Stdout) || jsonOutput {
+			closeOn(stream, os.Interrupt, os.Kill)
+			for stream.Next() {
+				fmt.Println(string(stream.Bytes()))
+			}
+			return stream.Err()
+		}
+		return traceAuditLogWithUI(stream)
+	case "error":
+		stream, err := client.TraceErrorLog()
+		if err != nil {
+			return err
+		}
+		defer stream.Close()
+
+		if !isTerm(os.Stdout) || jsonOutput {
+			closeOn(stream, os.Interrupt, os.Kill)
+			for stream.Next() {
+				fmt.Println(string(stream.Bytes()))
+			}
+			return stream.Err()
+		}
+		return traceErrorLogWithUI(stream)
+	default:
+		return fmt.Errorf("Unknown log event type: '%s'", typeFlag)
+	}
+}
+
+// traceAuditLogWithUI iterates over the audit log
+// event stream and prints a table-like UI to STDOUT.
+//
+// Each event is displayed as a new row and the UI is
+// automatically adjusted to the terminal window size.
+func traceAuditLogWithUI(stream *kes.AuditStream) error {
+	table := xterm.NewTable("Time", "Identity", "Status", "API Operations", "Response")
+	table.Header()[0].Width = 0.12
+	table.Header()[1].Width = 0.15
+	table.Header()[2].Width = 0.15
+	table.Header()[3].Width = 0.45
+	table.Header()[4].Width = 0.12
+
+	table.Header()[0].Alignment = xterm.AlignCenter
+	table.Header()[1].Alignment = xterm.AlignCenter
+	table.Header()[2].Alignment = xterm.AlignCenter
+	table.Header()[3].Alignment = xterm.AlignLeft
+	table.Header()[4].Alignment = xterm.AlignCenter
+
+	// Initialize the terminal UI and listen on resize
+	// events and Ctrl-C / Escape key events.
+	if err := ui.Init(); err != nil {
 		return err
 	}
-	defer stream.Close()
+	defer table.Draw() // Draw the table AFTER closing the UI one more time.
+	defer ui.Close()   // Closing the UI cleans the screen.
 
-	sigCh := make(chan os.Signal)
-	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
 	go func() {
-		<-sigCh
-		if err := stream.Close(); err != nil {
-			fmt.Fprintln(cli.Output(), err)
+		events := ui.PollEvents()
+		for {
+			switch event := <-events; {
+			case event.Type == ui.ResizeEvent:
+				table.Draw()
+			case event.ID == "<C-c>" || event.ID == "<Escape>":
+				if err := stream.Close(); err != nil {
+					fmt.Fprintln(os.Stderr, err)
+				}
+				return
+			}
 		}
 	}()
 
-	isTerminal := isTerm(os.Stdout)
+	var (
+		green = color.New(color.FgGreen)
+		red   = color.New(color.FgRed)
+	)
+	table.Draw()
 	for stream.Next() {
-		if !isTerminal || jsonOutput {
-			fmt.Println(string(stream.Bytes()))
-			continue
-		}
-
 		event := stream.Event()
-		identity := event.Request.Identity
-		if len(identity) > 7 {
-			identity = identity[:7]
-		}
+		hh, mm, ss := event.Time.Clock()
 
-		var status string
-		if runtime.GOOS == "windows" { // don't colorize on windows
-			status = fmt.Sprintf("[%d %s]", event.Response.StatusCode, http.StatusText(event.Response.StatusCode))
+		var (
+			identity = xterm.NewCell(event.Request.Identity)
+			status   = xterm.NewCell(fmt.Sprintf("%d %s", event.Response.StatusCode, http.StatusText(event.Response.StatusCode)))
+			path     = xterm.NewCell(event.Request.Path)
+			reqTime  = xterm.NewCell(fmt.Sprintf("%02d:%02d:%02d", hh, mm, ss))
+			respTime *xterm.Cell
+		)
+		if event.Response.StatusCode == http.StatusOK {
+			status.Color = green
 		} else {
-			identity = color.YellowString(identity)
-			if event.Response.StatusCode == http.StatusOK {
-				status = color.GreenString("[%d %s]", event.Response.StatusCode, http.StatusText(event.Response.StatusCode))
-			} else {
-				status = color.RedString("[%d %s]", event.Response.StatusCode, http.StatusText(event.Response.StatusCode))
-			}
+			status.Color = red
 		}
 
 		// Truncate duration values such that we show reasonable
 		// time values - like 1.05s or 345.76ms.
-		respTime := event.Response.Time
 		switch {
-		case respTime >= time.Second:
-			respTime = respTime.Truncate(10 * time.Millisecond)
-		case respTime >= time.Millisecond:
-			respTime = respTime.Truncate(10 * time.Microsecond)
+		case event.Response.Time >= time.Second:
+			respTime = xterm.NewCell(event.Response.Time.Truncate(10 * time.Millisecond).String())
+		case event.Response.Time >= time.Millisecond:
+			respTime = xterm.NewCell(event.Response.Time.Truncate(10 * time.Microsecond).String())
 		default:
-			respTime = respTime.Truncate(time.Microsecond)
+			respTime = xterm.NewCell(event.Response.Time.Truncate(time.Microsecond).String())
 		}
 
-		const format = "%s %s %-25s %10s\n"
-		fmt.Printf(format, identity, status, event.Request.Path, respTime)
+		table.AddRow(reqTime, identity, status, path, respTime)
+		table.Draw()
 	}
 	return stream.Err()
 }
+
+// traceErrorLogWithUI iterates over the error log
+// event stream and prints a table-like UI to STDOUT.
+//
+// Each event is displayed as a new row and the UI is
+// automatically adjusted to the terminal window size.
+func traceErrorLogWithUI(stream *kes.ErrorStream) error {
+	table := xterm.NewTable("Time", "Error")
+	table.Header()[0].Width = 0.12
+	table.Header()[1].Width = 0.87
+
+	table.Header()[0].Alignment = xterm.AlignCenter
+	table.Header()[1].Alignment = xterm.AlignLeft
+
+	// Initialize the terminal UI and listen on resize
+	// events and Ctrl-C / Escape key events.
+	if err := ui.Init(); err != nil {
+		return err
+	}
+	defer table.Draw() // Draw the table AFTER closing the UI one more time.
+	defer ui.Close()   // Closing the UI cleans the screen.
+
+	go func() {
+		events := ui.PollEvents()
+		for {
+			switch event := <-events; {
+			case event.Type == ui.ResizeEvent:
+				table.Draw()
+			case event.ID == "<C-c>" || event.ID == "<Escape>":
+				if err := stream.Close(); err != nil {
+					fmt.Fprintln(os.Stderr, err)
+				}
+				return
+			}
+		}
+	}()
+
+	table.Draw()
+	for stream.Next() {
+		// An error event message has the following form: YY/MM/DD hh/mm/ss <message>.
+		// We split this message into 3 segements:
+		//  1. YY/MM/DD
+		//  2. hh/mm/ss
+		//  3. <message>
+		// The 2nd segment is the day-time and 3rd segment is the actual error message.
+		// We replace any '\n' with a whitespace to avoid multi-line table rows.
+		segements := strings.SplitN(stream.Event().Message, " ", 3)
+		var (
+			message *xterm.Cell
+			reqTime *xterm.Cell
+		)
+		if len(segements) == 3 {
+			message = xterm.NewCell(strings.ReplaceAll(segements[2], "\n", " "))
+			reqTime = xterm.NewCell(segements[1])
+		} else {
+			hh, mm, ss := time.Now().Clock()
+
+			message = xterm.NewCell(strings.ReplaceAll(stream.Event().Message, "\n", " "))
+			reqTime = xterm.NewCell(fmt.Sprintf("%02d:%02d:%02d", hh, mm, ss))
+		}
+		table.AddRow(reqTime, message)
+		table.Draw()
+	}
+	return stream.Err()
+}
+
+// closeOn closes c if one of the given system signals
+// occurs. If c.Close() returns an error this error is
+// written to STDERR.
+func closeOn(c io.Closer, signals ...os.Signal) {
+	sigCh := make(chan os.Signal)
+	signal.Notify(sigCh, signals...)
+
+	go func() {
+		<-sigCh
+		if err := c.Close(); err != nil {
+			fmt.Fprintln(os.Stderr, err)
+		}
+	}()
+}

go.mod

@@ -5,11 +5,12 @@ go 1.13
 require (
 	github.com/aws/aws-sdk-go v1.26.3
 	github.com/fatih/color v1.7.0
+	github.com/gizak/termui/v3 v3.1.0
 	github.com/hashicorp/vault/api v1.0.4
 	github.com/kr/pretty v0.1.0 // indirect
 	github.com/secure-io/sio-go v0.3.0
 	github.com/stretchr/testify v1.4.0 // indirect
-	golang.org/x/crypto v0.0.0-20191117063200-497ca9f6d64f
+	golang.org/x/crypto v0.0.0-20200709230013-948cd5f35899
 	golang.org/x/sys v0.0.0-20190412213103-97732733099d
 	gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 // indirect
 	gopkg.in/yaml.v2 v2.2.4

go.sum

@@ -13,6 +13,8 @@ github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSs
 github.com/fatih/color v1.7.0 h1:DkWD4oS2D8LGGgTQ6IvwJJXSL5Vp2ffcQg58nFV38Ys=
 github.com/fatih/color v1.7.0/go.mod h1:Zm6kSWBoL9eyXnKyktHP6abPY2pDugNf5KwzbycvMj4=
 github.com/fatih/structs v1.1.0/go.mod h1:9NiDSp5zOcgEDl+j00MP/WkGVPOlPRLejGD8Ga6PJ7M=
+github.com/gizak/termui/v3 v3.1.0 h1:ZZmVDgwHl7gR7elfKf1xc4IudXZ5qqfDh4wExk4Iajc=
+github.com/gizak/termui/v3 v3.1.0/go.mod h1:bXQEBkJpzxUAKf0+xq9MSWAvWZlE7c+aidmyFlkYTrY=
 github.com/go-ldap/ldap v3.0.2+incompatible/go.mod h1:qfd9rJvER9Q0/D/Sqn1DfHRoBp40uXYvFoEVrNEPqRc=
 github.com/go-test/deep v1.0.2-0.20181118220953-042da051cf31/go.mod h1:wGDj63lr65AM2AQyKZd/NYHGb0R+1RLqB8NKt3aSFNA=
 github.com/golang/glog v0.0.0-20160126235308-23def4e6c14b/go.mod h1:SBH7ygxi8pfUlaOkMMuAQtPIUF8ecWP5IEl/CR7VP2Q=
@@ -64,16 +66,22 @@ github.com/mattn/go-colorable v0.0.9 h1:UVL0vNpWh04HeJXV0KLcaT7r06gOH2l4OW6ddYRU
 github.com/mattn/go-colorable v0.0.9/go.mod h1:9vuHe8Xs5qXnSaW/c/ABM9alt+Vo+STaOChaDxuIBZU=
 github.com/mattn/go-isatty v0.0.3 h1:ns/ykhmWi7G9O+8a448SecJU3nSMBXJfqQkl0upE1jI=
 github.com/mattn/go-isatty v0.0.3/go.mod h1:M+lRXTBqGeGNdLjl/ufCoiOlB5xdOkqRJdNxMWT7Zi4=
+github.com/mattn/go-runewidth v0.0.2 h1:UnlwIPBGaTZfPQ6T1IGzPI0EkYAQmT9fAEJ/poFC63o=
+github.com/mattn/go-runewidth v0.0.2/go.mod h1:LwmH8dsx7+W8Uxz3IHJYH5QSwggIsqBzpuz5H//U1FU=
 github.com/mitchellh/cli v1.0.0/go.mod h1:hNIlj7HEI86fIcpObd7a0FcrxTWetlwJDGcceTlRvqc=
 github.com/mitchellh/copystructure v1.0.0/go.mod h1:SNtv71yrdKgLRyLFxmLdkAbkKEFWgYaq1OVrnRcwhnw=
 github.com/mitchellh/go-homedir v1.1.0 h1:lukF9ziXFxDFPkA1vsr5zpc1XuPDn/wFntq5mG+4E0Y=
 github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
 github.com/mitchellh/go-testing-interface v0.0.0-20171004221916-a61a99592b77/go.mod h1:kRemZodwjscx+RGhAo8eIhFbs2+BFgRtFPeD/KE+zxI=
 github.com/mitchellh/go-testing-interface v1.0.0/go.mod h1:kRemZodwjscx+RGhAo8eIhFbs2+BFgRtFPeD/KE+zxI=
+github.com/mitchellh/go-wordwrap v0.0.0-20150314170334-ad45545899c7/go.mod h1:ZXFpozHsX6DPmq2I0TCekCxypsnAUbP2oI0UX1GXzOo=
+github.com/mitchellh/go-wordwrap v1.0.0 h1:6GlHJ/LTGMrIJbwgdqdl2eEH8o+Exx/0m8ir9Gns0u4=
 github.com/mitchellh/go-wordwrap v1.0.0/go.mod h1:ZXFpozHsX6DPmq2I0TCekCxypsnAUbP2oI0UX1GXzOo=
 github.com/mitchellh/mapstructure v1.1.2 h1:fmNYVwqnSfB9mZU6OS2O6GsXM+wcskZDuKQzvN1EDeE=
 github.com/mitchellh/mapstructure v1.1.2/go.mod h1:FVVH3fgwuzCH5S8UJGiWEs2h04kUh9fWfEaFds41c1Y=
 github.com/mitchellh/reflectwalk v1.0.0/go.mod h1:mSTlrgnPZtwu0c4WaC2kGObEpuNDbx0jmZXqmk4esnw=
+github.com/nsf/termbox-go v0.0.0-20190121233118-02980233997d h1:x3S6kxmy49zXVVyhcnrFqxvNVCBPb2KZ9hV2RBdS840=
+github.com/nsf/termbox-go v0.0.0-20190121233118-02980233997d/go.mod h1:IuKpRQcYE1Tfu+oAQqaLisqDeXgjyyltCfsaoYN18NQ=
 github.com/oklog/run v1.0.0/go.mod h1:dlhp/R75TPv97u0XWUtDeV/lRKWPKSdTuV0TZvrmrQA=
 github.com/pascaldekloe/goe v0.1.0/go.mod h1:lzWF7FIEvWOWxwDKqyGYQf6ZUaNfKdP144TG7ZOy1lc=
 github.com/pierrec/lz4 v2.0.5+incompatible h1:2xWsjqPFWcplujydGg4WmhC/6fZqK42wMM8aXeqhl0I=
@@ -93,9 +101,10 @@ github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UV
 github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20190513172903-22d7a77e9e5f h1:R423Cnkcp5JABoeemiGEPlt9tHXFfw5kvc0yqlxRPWo=
 golang.org/x/crypto v0.0.0-20190513172903-22d7a77e9e5f/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
-golang.org/x/crypto v0.0.0-20191117063200-497ca9f6d64f h1:kz4KIr+xcPUsI3VMoqWfPMvtnJ6MGfiVwsWSVzphMO4=
-golang.org/x/crypto v0.0.0-20191117063200-497ca9f6d64f/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/crypto v0.0.0-20200709230013-948cd5f35899 h1:DZhuSZLsGlFL4CmhA8BcRA0mnthyA/nZ00AqCUo7vHg=
+golang.org/x/crypto v0.0.0-20200709230013-948cd5f35899/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=
 golang.org/x/lint v0.0.0-20190227174305-5b3e6a55c961/go.mod h1:wehouNa3lNwaWXcvxsM5YxQ5yQlVC4a0KAMCusXpPoU=