moncheck: fix error reporting of daedlines

The deadlines were wrong all over the place, so this commit finally
fixes that.

cmd/moncheck/main.go

@@ -4,11 +4,15 @@ import (
 	"bytes"
 	"context"
 	"database/sql"
+	"database/sql/driver"
 	"encoding/json"
 	"flag"
+	"fmt"
 	"io/ioutil"
 	"log"
 	"os/exec"
+	"strconv"
+	"strings"
 	"sync"
 	"syscall"
 	"time"
@@ -25,6 +29,8 @@ type (
 		DB   string `json:"db"`
 		Wait string `json:"wait"`
 	}
+
+	States []int
 )
 
 func main() {
@@ -73,7 +79,7 @@ func check(thread int, db *sql.DB, waitDuration time.Duration) {
 		var (
 			id      int64
 			cmdLine []string
-			states  []int64
+			states  States
 			notify  bool
 		)
 		found := false
@@ -83,7 +89,7 @@ func check(thread int, db *sql.DB, waitDuration time.Duration) {
 				tx.Rollback()
 				break
 			}
-			if err := rows.Scan(&id, pq.Array(&cmdLine), pq.Array(&states), &notify); err != nil {
+			if err := rows.Scan(&id, pq.Array(&cmdLine), &states, &notify); err != nil {
 				log.Printf("could not scan values: %s", err)
 				tx.Rollback()
 				break
@@ -95,46 +101,44 @@ func check(thread int, db *sql.DB, waitDuration time.Duration) {
 			tx.Rollback()
 			continue
 		}
-		statePos := 5
-		if len(states) < 6 {
-			statePos = len(states)
-		}
 		ctx, cancel := context.WithTimeout(context.Background(), 1*time.Second)
 		cmd := exec.CommandContext(ctx, cmdLine[0], cmdLine[1:]...)
 		output := bytes.NewBuffer([]byte{})
 		cmd.Stdout = output
 		cmd.Stderr = output
-		if err != nil && err == context.Canceled {
+		err = cmd.Run()
+		if err != nil && ctx.Err() == context.DeadlineExceeded {
 			log.Printf("[%d] check took too long: %s", id, err)
+			cancel()
 			// TODO which state to choose?
 			// TODO add notification handler
 			// TODO all this casting should be done better
-			states = append([]int64{1}, states[:statePos]...)
+			states.Add(99)
+			output.Write([]byte(ctx.Err().Error()))
 		} else if err != nil {
 			cancel()
-			exitErr, ok := err.(*exec.ExitError)
+			status, ok := cmd.ProcessState.Sys().(syscall.WaitStatus)
 			if !ok {
 				log.Printf("[%d]error running check: %s", id, err)
-				states = append([]int64{1}, states[:statePos]...)
+				states.Add(1)
 			} else {
-				status, ok := exitErr.Sys().(syscall.WaitStatus)
-				if !ok {
-				} else {
-					states = append([]int64{int64(status.ExitStatus())}, states[:statePos]...)
-				}
+				log.Printf("%s", cmd.ProcessState.String())
+				states.Add(status.ExitStatus())
 			}
 		} else {
 			cancel()
-			states = append([]int64{0}, states[:statePos]...)
+			states.Add(0)
 		}
+		msg := output.String()
 
-		if _, err := tx.Exec("update active_checks set next_time = now() + intval, states = $2 where check_id = $1", id, pq.Array(&states)); err != nil {
+		if _, err := tx.Exec("update active_checks set next_time = now() + intval, states = $2 where check_id = $1", id, &states); err != nil {
 			log.Printf("[%d] could not update row '%d': %s", thread, id, err)
 			tx.Rollback()
 			continue
 		}
+		log.Printf("meh %s", output.String())
 		if notify {
-			if _, err := tx.Exec("insert into notifications(check_id, states, output) values ($1, $2, $3);", &id, pq.Array(&states), output.Bytes()); err != nil {
+			if _, err := tx.Exec("insert into notifications(check_id, states, output) values ($1, $2, $3);", &id, &states, &msg); err != nil {
 				log.Printf("[%d] could not create notification for '%d': %s", thread, id, err)
 				tx.Rollback()
 				continue
@@ -143,3 +147,60 @@ func check(thread int, db *sql.DB, waitDuration time.Duration) {
 		tx.Commit()
 	}
 }
+
+func (s *States) Value() (driver.Value, error) {
+	last := len(*s)
+	if last == 0 {
+		return "{}", nil
+	}
+	result := strings.Builder{}
+	_, err := result.WriteString("{")
+	if err != nil {
+		return "", fmt.Errorf("could not write to buffer: %s", err)
+	}
+	for i, state := range *s {
+		if _, err := fmt.Fprintf(&result, "%d", state); err != nil {
+			return "", fmt.Errorf("could not write to buffer: %s", err)
+		}
+		if i < last-1 {
+			if _, err := result.WriteString(","); err != nil {
+				return "", fmt.Errorf("could not write to buffer: %s", err)
+			}
+		}
+	}
+	if _, err := result.WriteString("}"); err != nil {
+		return "", fmt.Errorf("could not write to buffer: %s", err)
+	}
+	return result.String(), nil
+}
+
+func (s *States) Scan(src interface{}) error {
+	switch src := src.(type) {
+	case []byte:
+		tmp := bytes.Trim(src, "{}")
+		states := bytes.Split(tmp, []byte(","))
+		result := make([]int, len(states))
+		for i, state := range states {
+			var err error
+			result[i], err = strconv.Atoi(string(state))
+			if err != nil {
+				return fmt.Errorf("could not parse element %s: %s", state, err)
+			}
+		}
+		*s = result
+		return nil
+	default:
+		return fmt.Errorf("could not convert %T to states", src)
+	}
+}
+
+// Append prepends the new state before all others.
+func (s *States) Add(state int) {
+	vals := *s
+	statePos := 5
+	if len(vals) < 6 {
+		statePos = len(vals)
+	}
+	*s = append([]int{state}, vals[:statePos]...)
+	return
+}