Improved error checking

collectors/customCmdMetric.go

@@ -8,10 +8,11 @@
 package collectors
 
 import (
+	"bytes"
 	"encoding/json"
 	"errors"
 	"fmt"
-	"log"
+	"io"
 	"os"
 	"os/exec"
 	"slices"
@@ -20,7 +21,9 @@ import (
 
 	cclog "github.com/ClusterCockpit/cc-lib/v2/ccLogger"
 	lp "github.com/ClusterCockpit/cc-lib/v2/ccMessage"
-	influx "github.com/influxdata/line-protocol"
+
+	receivers "github.com/ClusterCockpit/cc-lib/v2/receivers"
+	lp2 "github.com/influxdata/line-protocol/v2/lineprotocol"
 )
 
 const CUSTOMCMDPATH = `/home/unrz139/Work/cc-metric-collector/collectors/custom`
@@ -33,115 +36,155 @@ type CustomCmdCollectorConfig struct {
 
 type CustomCmdCollector struct {
 	metricCollector
-	handler  *influx.MetricHandler
+	config         CustomCmdCollectorConfig
-	parser   *influx.Parser
+	cmdFieldsSlice [][]string
-	config   CustomCmdCollectorConfig
+	files          []string
-	commands []string
-	files    []string
 }
 
 func (m *CustomCmdCollector) Init(config json.RawMessage) error {
-	var err error
 	m.name = "CustomCmdCollector"
 	m.parallel = true
 	m.meta = map[string]string{
 		"source": m.name,
 		"group":  "Custom",
 	}
+
+	// Read configuration
 	if len(config) > 0 {
-		err = json.Unmarshal(config, &m.config)
+		if err := json.Unmarshal(config, &m.config); err != nil {
-		if err != nil {
 			return fmt.Errorf("%s Init(): json.Unmarshal() call failed: %w", m.name, err)
 		}
 	}
+
+	// Setup
 	if err := m.setup(); err != nil {
 		return fmt.Errorf("%s Init(): setup() call failed: %w", m.name, err)
 	}
+
+	// Check if command can be executed
 	for _, c := range m.config.Commands {
-		cmdfields := strings.Fields(c)
+		cmdFields := strings.Fields(c)
-		command := exec.Command(cmdfields[0], cmdfields[1:]...)
+		command := exec.Command(cmdFields[0], cmdFields[1:]...)
-		_, err = command.Output()
+		if _, err := command.Output(); err != nil {
-		if err == nil {
-			m.commands = append(m.commands, c)
-		} else {
 			cclog.ComponentWarn(
 				m.name,
-				fmt.Sprintf("%s Init(): Execution of command \"%s\" failed: %v", m.name, command.String(), err),
+				fmt.Sprintf("%s Init(): Execution of command \"%s\" failed: %v", m.name, command.String(), err))
-			)
 			continue
 		}
+		m.cmdFieldsSlice = append(m.cmdFieldsSlice, cmdFields)
 	}
-	for _, f := range m.config.Files {
+
-		_, err = os.ReadFile(f)
+	// Check if file can be read
-		if err == nil {
+	for _, fileName := range m.config.Files {
-			m.files = append(m.files, f)
+		if _, err := os.ReadFile(fileName); err != nil {
-		} else {
 			cclog.ComponentWarn(
 				m.name,
-				fmt.Sprintf("%s Init(): Reading of file \"%s\" failed: %v", m.name, f, err),
+				fmt.Sprintf("%s Init(): Reading of file \"%s\" failed: %v", m.name, fileName, err))
-			)
 			continue
 		}
+		m.files = append(m.files, fileName)
 	}
-	if len(m.files) == 0 && len(m.commands) == 0 {
+
+	if len(m.files) == 0 && len(m.cmdFieldsSlice) == 0 {
 		return errors.New("no metrics to collect")
 	}
-	m.handler = influx.NewMetricHandler()
-	m.parser = influx.NewParser(m.handler)
-	m.parser.SetTimeFunc(DefaultTime)
 	m.init = true
 	return nil
 }
 
-var DefaultTime = func() time.Time {
-	return time.Unix(42, 0)
-}
-
 func (m *CustomCmdCollector) Read(interval time.Duration, output chan lp.CCMessage) {
 	if !m.init {
 		return
 	}
-	for _, cmd := range m.commands {
+
-		cmdfields := strings.Fields(cmd)
+	// Execute configured commands
-		command := exec.Command(cmdfields[0], cmdfields[1:]...)
+	for _, cmdFields := range m.cmdFieldsSlice {
-		if err := command.Wait(); err != nil {
+		command := exec.Command(cmdFields[0], cmdFields[1:]...)
-			log.Print(err)
+		stdout, err := command.StdoutPipe()
-			continue
-		}
-		stdout, err := command.Output()
 		if err != nil {
-			log.Print(err)
+			cclog.ComponentError(
+				m.name,
+				fmt.Sprintf("Read(): Failed to create stdout pipe for command \"%s\": %v", command.String(), err),
+			)
 			continue
 		}
-		cmdmetrics, err := m.parser.Parse(stdout)
+		errBuf := new(bytes.Buffer)
-		if err != nil {
+		command.Stderr = errBuf
-			log.Print(err)
+
+		// Start command
+		if err := command.Start(); err != nil {
+			cclog.ComponentError(
+				m.name,
+				fmt.Sprintf("Read(): Failed to start command \"%s\": %v", command.String(), err),
+			)
 			continue
 		}
-		for _, c := range cmdmetrics {
+
-			if slices.Contains(m.config.ExcludeMetrics, c.Name()) {
+		// Read and decode influxDB line-protocol from command output
+		d := lp2.NewDecoder(stdout)
+		for d.Next() {
+			metric, err := receivers.DecodeInfluxMessage(d)
+			if err != nil {
+				cclog.ComponentError(
+					m.name,
+					fmt.Sprintf("Read(): Failed to decode influx Message: %v", err),
+				)
 				continue
 			}
+			if slices.Contains(m.config.ExcludeMetrics, metric.Name()) {
+				continue
+			}
+			output <- metric
+		}
 
-			output <- lp.FromInfluxMetric(c)
+		// Wait for command end
+		if err := command.Wait(); err != nil {
+			errMsg, _ := io.ReadAll(errBuf)
+			cclog.ComponentError(
+				m.name,
+				fmt.Sprintf("Read(): Failed to wait for the end of command \"%s\": %v\n", command.String(), err),
+			)
+			cclog.ComponentError(
+				m.name,
+				fmt.Sprintf("Read(): command stderr: \"%s\"\n", strings.TrimSpace(string(errMsg))))
+			continue
 		}
 	}
-	for _, file := range m.files {
+
-		buffer, err := os.ReadFile(file)
+	// Read configured files
+	for _, filename := range m.files {
+		file, err := os.Open(filename)
 		if err != nil {
-			log.Print(err)
+			cclog.ComponentError(
-			return
+				m.name,
-		}
+				fmt.Sprintf("Read(): Failed to open file \"%s\": %v\n", filename, err),
-		fmetrics, err := m.parser.Parse(buffer)
+			)
-		if err != nil {
-			log.Print(err)
 			continue
 		}
-		for _, f := range fmetrics {
+
-			if slices.Contains(m.config.ExcludeMetrics, f.Name()) {
+		// Read and decode influxDB line-protocol from file
+		d := lp2.NewDecoder(file)
+		for d.Next() {
+			metric, err := receivers.DecodeInfluxMessage(d)
+			if err != nil {
+				cclog.ComponentError(
+					m.name,
+					fmt.Sprintf("Read(): Failed to decode influx Message: %v", err),
+				)
 				continue
 			}
-			output <- lp.FromInfluxMetric(f)
+			if slices.Contains(m.config.ExcludeMetrics, metric.Name()) {
+				continue
+			}
+			output <- metric
+		}
+
+		if err := file.Close(); err != nil {
+			cclog.ComponentError(
+				m.name,
+				fmt.Sprintf("Read(): Failed to close file \"%s\": %v\n", filename, err),
+			)
+			continue
 		}
 	}
 }