Implement HUD

.github/workflows/build.yml

@@ -0,0 +1,17 @@
+name: build
+
+on:
+  - push
+  - pull_request
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - uses: actions/setup-go@v2
+        with:
+          go-version: 1.17.8
+
+      - run: make

.github/workflows/release.yml

@@ -0,0 +1,18 @@
+name: release
+
+on:
+  push:
+    tags:
+      - v*
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - run: go build -o hud main.go
+
+      - uses: softprops/action-gh-release@v1
+        with:
+          files: hud

.gitignore

@@ -0,0 +1,22 @@
+# https://raw.githubusercontent.com/github/gitignore/master/Go.gitignore
+# If you prefer the allow list template instead of the deny list, see community template:
+# https://github.com/github/gitignore/blob/main/community/Golang/Go.AllowList.gitignore
+#
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
+
+# Go workspace file
+go.work

Makefile

@@ -0,0 +1,7 @@
+all: test
+
+fmt:
+	go fmt ./...
+
+test:
+	go test ./... -coverprofile cover.out

README.md

@@ -1,2 +1,3 @@
-# hud
-Head-up Display for Linux
+# HUD: Head-up Display for Linux
+
+[![build](https://github.com/fengye87/hud/actions/workflows/build.yml/badge.svg)](https://github.com/fengye87/hud/actions/workflows/build.yml)

go.mod

@@ -0,0 +1,26 @@
+module github.com/fengye87/hud
+
+go 1.17
+
+require (
+	github.com/docker/libnetwork v0.8.0-dev.2.0.20220315221942-339b972b464e
+	github.com/gdamore/tcell/v2 v2.5.1
+	github.com/rivo/tview v0.0.0-20220307222120-9994674d60a8
+	github.com/vishvananda/netlink v1.1.0
+	gopkg.in/ini.v1 v1.66.4
+)
+
+require (
+	github.com/docker/docker v20.10.16+incompatible // indirect
+	github.com/gdamore/encoding v1.0.0 // indirect
+	github.com/ishidawataru/sctp v0.0.0-20210707070123-9a39160e9062 // indirect
+	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
+	github.com/mattn/go-runewidth v0.0.13 // indirect
+	github.com/rivo/uniseg v0.2.0 // indirect
+	github.com/sirupsen/logrus v1.8.1 // indirect
+	github.com/vishvananda/netns v0.0.0-20191106174202-0a2b9b5464df // indirect
+	golang.org/x/sys v0.0.0-20220318055525-2edf467146b5 // indirect
+	golang.org/x/term v0.0.0-20210220032956-6a3ed077a48d // indirect
+	golang.org/x/text v0.3.7 // indirect
+	gotest.tools/v3 v3.2.0 // indirect
+)

go.sum

@@ -0,0 +1,73 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
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+github.com/docker/docker v20.10.16+incompatible/go.mod h1:eEKB0N0r5NX/I1kEveEz05bcu8tLC/8azJZsviup8Sk=
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+github.com/docker/libnetwork v0.8.0-dev.2.0.20220315221942-339b972b464e/go.mod h1:93m0aTqz6z+g32wla4l4WxTrdtvBRmVzYRkYvasA5Z8=
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+gopkg.in/ini.v1 v1.66.4 h1:SsAcf+mM7mRZo2nJNGt8mZCjG8ZRaNGMURJw7BsIST4=
+gopkg.in/ini.v1 v1.66.4/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k=
+gotest.tools/v3 v3.2.0 h1:I0DwBVMGAx26dttAj1BtJLAkVGncrkkUXfJLC4Flt/I=
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hud.service

@@ -0,0 +1,10 @@
+[Service]
+ExecStart=/usr/local/bin/hud
+StandardInput=tty
+StandardOutput=tty
+TTYPath=/dev/tty1
+TTYReset=yes
+Restart=always
+
+[Install]
+WantedBy=multi-user.target

install.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+wget -O /usr/local/bin/hud https://github.com/fengye87/hud/releases/download/v0.1.0/hud
+chmod +x /usr/local/bin/hud
+wget -O /etc/systemd/system/hud.service https://raw.githubusercontent.com/fengye87/hud/main/hud.service
+
+systemctl disable --now [email protected]
+systemctl enable --now hud.service

main.go

@@ -0,0 +1,198 @@
+package main
+
+import (
+	"fmt"
+	"net"
+	"os"
+	"os/exec"
+	"os/signal"
+	"strconv"
+	"strings"
+	"syscall"
+	"time"
+
+	"github.com/docker/libnetwork/resolvconf"
+	"github.com/docker/libnetwork/types"
+	"github.com/gdamore/tcell/v2"
+	"github.com/rivo/tview"
+	"github.com/vishvananda/netlink"
+	"gopkg.in/ini.v1"
+)
+
+const JournalMaxLines = 120
+
+func main() {
+	release, err := getOSRelease()
+	if err != nil {
+		panic(err)
+	}
+
+	app := tview.NewApplication()
+	app.SetInputCapture(func(event *tcell.EventKey) *tcell.EventKey { return event })
+	if err := setupSignalHandler(app); err != nil {
+		panic(err)
+	}
+
+	headerTV := tview.NewTextView().SetTextAlign(tview.AlignCenter).SetTextColor(tcell.ColorTeal).SetChangedFunc(func() { app.Draw() })
+	headerTV.SetText("\n" + release)
+
+	infoTV := tview.NewTextView().SetDynamicColors(true).SetChangedFunc(func() { app.Draw() })
+
+	journalTV := tview.NewTextView().ScrollToEnd().SetChangedFunc(func() { app.Draw() })
+	journalTV.SetMaxLines(JournalMaxLines)
+	journalctl := exec.Command("journalctl", "--no-hostname", "-n", strconv.Itoa(JournalMaxLines), "-f")
+	journalctl.Stdout = journalTV
+	if err := journalctl.Start(); err != nil {
+		panic(err)
+	}
+
+	flex := tview.NewFlex().SetDirection(tview.FlexRow).AddItem(headerTV, 3, 0, false).AddItem(infoTV, 0, 0, false).AddItem(journalTV, 0, 1, false)
+
+	go func() {
+		hostnameInfo := []string{"Hostname", ""}
+		ipInfo := []string{"IP address", ""}
+		gatewayInfo := []string{"Gateway address", ""}
+		dnsInfo := []string{"DNS nameservers", ""}
+		timeInfo := []string{"Time", ""}
+		infoItems := [][]string{hostnameInfo, ipInfo, gatewayInfo, dnsInfo, timeInfo}
+		lastUpdateTime := time.Time{}
+
+		for {
+			if time.Now().After(lastUpdateTime.Add(time.Minute)) {
+				hostname, _ := getHostname()
+				hostnameInfo[1] = hostname
+
+				link, _ := getDefaultLink()
+				if link != nil {
+					addr, _ := getLinkAddr(link)
+					if addr != nil {
+						ipInfo[1] = addr.IPNet.String()
+					}
+
+					gateway, _ := getLinkGateway(link)
+					if gateway != nil {
+						gatewayInfo[1] = gateway.String()
+					}
+				}
+
+				nameservers, _ := getNameservers()
+				dnsInfo[1] = strings.Join(nameservers, " ")
+			}
+
+			timeInfo[1] = time.Now().Format(time.RFC1123Z)
+
+			_, _, infoTVWidth, _ := infoTV.GetRect()
+			var infoLines []string
+			for _, info := range infoItems {
+				label := info[0]
+				paddingLen := infoTVWidth/2 - len(label) - 2
+				if paddingLen < 0 {
+					paddingLen = 0
+				}
+
+				value := info[1]
+				if value == "" {
+					value = "[:red]NOT SET[:-]"
+				}
+
+				infoLines = append(infoLines, fmt.Sprintf("%s[::b]%s[::-]: %s", strings.Repeat(" ", paddingLen), label, value))
+			}
+
+			infoTV.SetText(strings.Join(infoLines, "\n"))
+			flex.ResizeItem(infoTV, len(infoLines)+1, 0)
+
+			time.Sleep(time.Second)
+		}
+	}()
+
+	if err := app.SetRoot(flex, true).Run(); err != nil {
+		panic(err)
+	}
+}
+
+func setupSignalHandler(app *tview.Application) error {
+	printkPath := "/proc/sys/kernel/printk"
+	printk, err := os.ReadFile(printkPath)
+	if err != nil {
+		return fmt.Errorf("get printk: %s", err)
+	}
+
+	sigs := make(chan os.Signal, 1)
+	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM, os.Interrupt)
+	go func() {
+		<-sigs
+
+		os.WriteFile(printkPath, printk, 0644)
+		app.Stop()
+	}()
+
+	if err := os.WriteFile(printkPath, []byte("0 0 0 0"), 0644); err != nil {
+		return fmt.Errorf("set printk: %s", err)
+	}
+	return nil
+}
+
+func getOSRelease() (string, error) {
+	info, err := ini.Load("/etc/os-release")
+	if err != nil {
+		return "", fmt.Errorf("read OS info: %s", err)
+	}
+	return info.Section("").Key("PRETTY_NAME").String(), nil
+}
+
+func getHostname() (string, error) {
+	return os.Hostname()
+}
+
+func getDefaultLink() (netlink.Link, error) {
+	links, err := netlink.LinkList()
+	if err != nil {
+		return nil, fmt.Errorf("list links: %s", err)
+	}
+
+	for _, link := range links {
+		routes, err := netlink.RouteList(link, netlink.FAMILY_V4)
+		if err != nil {
+			return nil, fmt.Errorf("list routes of link %q: %s", link.Attrs().Name, err)
+		}
+
+		for _, route := range routes {
+			if route.Dst == nil {
+				return link, nil
+			}
+		}
+	}
+	return nil, nil
+}
+
+func getLinkAddr(link netlink.Link) (*netlink.Addr, error) {
+	addrs, err := netlink.AddrList(link, netlink.FAMILY_V4)
+	if err != nil {
+		return nil, fmt.Errorf("list addrs: %s", err)
+	}
+
+	if len(addrs) > 0 {
+		return &addrs[0], nil
+	}
+	return nil, nil
+}
+
+func getLinkGateway(link netlink.Link) (net.IP, error) {
+	routes, err := netlink.RouteList(link, netlink.FAMILY_V4)
+	if err != nil {
+		return nil, fmt.Errorf("list routes: %s", err)
+	}
+
+	if len(routes) > 0 {
+		return routes[0].Gw, nil
+	}
+	return nil, nil
+}
+
+func getNameservers() ([]string, error) {
+	rc, err := resolvconf.Get()
+	if err != nil {
+		return nil, fmt.Errorf("get resolvconf: %s", err)
+	}
+	return resolvconf.GetNameservers(rc.Content, types.IPv4), nil
+}