Removed dist and added cache to monitor

monitor/service.go

@@ -1,27 +1,38 @@
 package monitor
 
 import (
-	"bytes"
 	"log"
 	"os"
 	"os/exec"
 	"path"
 	"strings"
+	"time"
 )
 
 type Config struct {
-	ScriptsDir string `json:"scriptsDir"`
+	ScriptsDir   string
+	CacheTimeout time.Duration
+}
+
+type cacheEntry struct {
+	creationTime time.Time
+
+	output string
 }
 
 type Service struct {
 	Config *Config
 
-	scriptPaths map[string]string
+	scriptPaths       map[string]string
+	scriptOutputCache map[string]cacheEntry
 }
 
 func NewService(config *Config) *Service {
 	return &Service{
 		Config: config,
+
+		scriptPaths:       map[string]string{},
+		scriptOutputCache: map[string]cacheEntry{},
 	}
 }
 
@@ -41,21 +52,31 @@ func (s *Service) LoadScripts() error {
 	return nil
 }
 
-// TODO: Add caching
-func (s *Service) GetLastOutput(command string) (string, error) {
+func (s *Service) GetOutput(command string) (string, error) {
+	// check if output is present in cache
+	if entry, found := s.scriptOutputCache[command]; found {
+		// check if cached value is expired
+		if time.Now().Before(entry.creationTime.Add(s.Config.CacheTimeout)) {
+			log.Printf("Retrieving output of %q from cache", command)
+			return entry.output, nil
+		}
+	}
+
 	args := strings.Fields(command)
 
 	log.Printf("Running script %q with args %v", args[0], args[1:])
 
 	scriptPath := s.scriptPaths[args[0]]
 
-	cmd := exec.Command(scriptPath, args[1:]...)
-	var b bytes.Buffer
-	cmd.Stdout = &b
-
-	if err := cmd.Run(); err != nil {
+	bytes, err := exec.Command(scriptPath, args[1:]...).Output()
+	if err != nil {
 		return "", err
 	}
 
-	return b.String(), nil
+	output := string(bytes)
+
+	log.Printf("Caching output of %q", command)
+	s.scriptOutputCache[command] = cacheEntry{time.Now(), output}
+
+	return output, nil
 }