monfront - add initial version

This version can already show the list of checks, their last state and
add ways to manipulate the check or active check.

1 files changed, 254 insertions, 0 deletions

diff --git a/cmd/monfront/main.go b/cmd/monfront/main.go
new file mode 100644
index 0000000..544d4f3
--- /dev/null
+++ b/cmd/monfront/main.go
@@ -0,0 +1,254 @@
+package main
+
+import (
+	"database/sql"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"html"
+	"html/template"
+	"io/ioutil"
+	"log"
+	"net/http"
+	"time"
+
+	"github.com/lib/pq"
+)
+
+var (
+	configPath = flag.String("config", "monfront.conf", "path to the config file")
+	DB         *sql.DB
+)
+
+type (
+	Config struct {
+		DB     string `json:"db"`
+		Listen string `json:"listen"`
+	}
+)
+
+func main() {
+	flag.Parse()
+
+	raw, err := ioutil.ReadFile(*configPath)
+	if err != nil {
+		log.Fatalf("could not read config: %s", err)
+	}
+	config := Config{}
+	if err := json.Unmarshal(raw, &config); err != nil {
+		log.Fatalf("could not parse config: %s", err)
+	}
+
+	db, err := sql.Open("postgres", config.DB)
+	if err != nil {
+		log.Fatalf("could not open database connection: %s", err)
+	}
+	DB = db
+
+	http.HandleFunc("/", showChecks)
+	http.HandleFunc("/action", checkAction)
+	http.ListenAndServe(config.Listen, nil)
+}
+
+func checkAction(w http.ResponseWriter, r *http.Request) {
+	if r.Method != "POST" {
+		w.WriteHeader(http.StatusMethodNotAllowed)
+		w.Write([]byte("method is not supported"))
+		return
+	}
+	if err := r.ParseForm(); err != nil {
+		w.WriteHeader(http.StatusBadRequest)
+		fmt.Fprintf(w, "could not parse parameters: %s", err)
+		return
+	}
+	checks := r.PostForm["checks"]
+	action := r.PostForm["action"]
+	if len(action) == 0 || action[0] == "" || len(checks) == 0 {
+		w.Header()["Location"] = []string{"/"}
+		w.WriteHeader(http.StatusSeeOther)
+		return
+	}
+	setTable := "checks"
+	setClause := ""
+	switch action[0] {
+	case "mute":
+		setClause = "notify = false"
+	case "unmute":
+		setClause = "notify = true"
+	case "enable":
+		setClause = "enabled = true"
+	case "disable":
+		setClause = "enabled = false"
+	case "reschedule":
+		setClause = "next_time = now()"
+		setTable = "active_checks"
+	case "ack":
+		setClause = "acknowledged = true"
+		setTable = "active_checks"
+	case "comment":
+		if len(r.PostForm["comment"]) == 0 {
+			w.WriteHeader(http.StatusBadRequest)
+			fmt.Fprintf(w, "no comment sent")
+			return
+		}
+		comment := r.PostForm["comment"][0]
+		_, err := DB.Exec(
+			"update active_checks set notice = $2 where check_id = any ($1::int[]);",
+			pq.Array(&checks),
+			html.EscapeString(comment))
+		if err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			fmt.Fprintf(w, "could not store changes")
+			log.Printf("could not adjust checks %#v: %s", checks, err)
+			return
+		}
+		w.Header()["Location"] = []string{"/"}
+		w.WriteHeader(http.StatusSeeOther)
+		return
+	default:
+		w.WriteHeader(http.StatusNotFound)
+		fmt.Fprintf(w, "unknown action %s", action)
+		return
+	}
+	whereColumn := "id"
+	if setTable == "active_checks" {
+		whereColumn = "check_id"
+	}
+
+	_, err := DB.Exec("update "+setTable+" set "+setClause+" where "+whereColumn+" = any ($1::int[]);", pq.Array(&checks))
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		fmt.Fprintf(w, "could not store changes")
+		log.Printf("could not adjust checks %#v: %s", checks, err)
+		return
+	}
+	w.Header()["Location"] = []string{"/"}
+	w.WriteHeader(http.StatusSeeOther)
+	return
+}
+
+func showChecks(w http.ResponseWriter, r *http.Request) {
+	rows, err := DB.Query(SQLShowChecks)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte("problems with the database"))
+		log.Printf("could not get check list: %s", err)
+		return
+	}
+
+	type check struct {
+		Name        string
+		CommandName string
+		CheckID     int64
+		State       int
+		Notify      bool
+		Enabled     bool
+		Notice      sql.NullString
+		NextTime    time.Time
+		Msg         string
+	}
+	checks := []check{}
+	for rows.Next() {
+		c := check{}
+		err := rows.Scan(&c.CheckID, &c.Name, &c.CommandName, &c.State, &c.Notify, &c.Enabled, &c.Notice, &c.NextTime, &c.Msg)
+		if err != nil {
+			w.WriteHeader(http.StatusInternalServerError)
+			w.Write([]byte("problems with the database"))
+			log.Printf("could not get check list: %s", err)
+			return
+		}
+		checks = append(checks, c)
+	}
+	tmpl, err := template.New("checklist").Parse(TmplCheckList)
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte("problems with a template"))
+		log.Printf("could not parse template: %s", err)
+		return
+	}
+	w.Header()["Content-Type"] = []string{"text/html"}
+	if err := tmpl.Execute(w, checks); err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		w.Write([]byte("problem with a template"))
+		log.Printf("could not execute template: %s", err)
+		return
+	}
+	return
+}
+
+var (
+	SQLShowChecks = `select c.id, n.name, co.name, ac.states[1] as state, ac.notify,
+	ac.enabled, ac.notice, ac.next_time, ac.msg
+  from active_checks ac
+	join checks c on ac.check_id = c.id
+	join nodes n on c.node_id = n.id
+	join commands co on c.command_id = co.id
+	order by n.name, co.name;`
+)
+
+var (
+	TmplCheckList = `<doctype html>
+<html>
+  <head>
+		<title>check list</title>
+		<style type="text/css">
+			* { font-size: 100%; }
+			form section {
+				display: flex;
+				flex-direction: row;
+				justify-content: center;
+				align-items: flex-start;
+			}
+			form menu { order: 1; }
+			form content { order: 2; flex-grow: 1; }
+			form menu { display: flex; flex-direction: column; }
+			form menu > * { margin: 0.5em; }
+			table td, table th { padding: 0.5em; }
+		  td.state-0 { background: green; }
+		  td.state-1 { background: orange; }
+		  td.state-2 { background: red; }
+		  td.state-99 { background: gray; }
+		</style>
+	</head>
+	<body>
+		<form method="post" action="/action">
+			<section>
+				<menu>
+					<div class="option">
+					<label for="action">Action</label>
+					<select name="action">
+					  <option value="reschedule">run now</option>
+						<option value="mute">mute</option>
+						<option value="unmute">unmute</option>
+						<option value="ack">acknowledge</option>
+						<option value="disable">disable</option>
+						<option value="enable">enable</option>
+						<option value="comment">comment</option>
+					</select>
+					</div>
+					<div class="option">
+					<label for="comment">comment</label>
+					<input name="comment" />
+					</div>
+					<button type="submit">submit</button>
+				</menu>
+				<content>
+					<table>
+						<thead><tr><th></th><th>host</th><th>status</th><th>next check</th><th>message</th></tr></thead>
+						<tbody>
+						{{ range . }}
+						<tr>
+							<td><input type="checkbox" name="checks" value="{{ .CheckID }}" /></td>
+							<td>{{ .Name }}</td>
+							<td class="state-{{ .State }}">{{ .CommandName }} - {{ .State }}</td>
+							<td>{{ .NextTime.Format "2006.01.02 15:04:05" }}</td>
+							<td><pre>{{ .Msg }}</pre></td>
+						</tr>
+						{{ end }}
+						</tbody>
+					</table>
+				</content>
+		</form>
+  </body>
+</html>`
+)