feat(capture): show output progress during capture (#41)

* feat(capture): show otuput progress during capture

Signed-off-by: Alessio Greggi <ale_grey_91@hotmail.it>
Co-authored-by: ccoVeille <3875889+ccoVeille@users.noreply.github.com>

cmd/capture.go

@@ -26,6 +26,7 @@ import (
 
 var functionSymbols string
 var commandOutput bool
+var commandError bool
 var libbpfOutput bool
 var save bool
 var directory string
@@ -50,7 +51,7 @@ by passing the function name symbol and the binary args.
 		for _, functionSymbol := range functionSymbolList {
 			syscalls, err := captor.Capture(functionSymbol, args, captureOpts)
 			if err != nil {
-				fmt.Printf("error capturing syscall: %w", err)
+				fmt.Printf("error capturing syscall: %v", err)
 			}
 
 			saveOpts := writer.WriteOptions{
@@ -72,7 +73,8 @@ func init() {
 	captureCmd.Flags().StringVarP(&functionSymbols, "functions", "f", "", "Name of the function symbols to be traced")
 	captureCmd.MarkFlagRequired("functions")
 
-	captureCmd.Flags().BoolVarP(&commandOutput, "include-cmd-output", "c", false, "Include the executed command output")
+	captureCmd.Flags().BoolVarP(&commandOutput, "include-cmd-stdout", "c", false, "Include the executed command output")
+	captureCmd.Flags().BoolVarP(&commandError, "include-cmd-stderr", "e", false, "Include the executed command error")
 
 	captureCmd.Flags().BoolVarP(&libbpfOutput, "include-libbpf-output", "l", false, "Include the libbpf output")
 

cmd/hunt.go

@@ -72,7 +72,7 @@ var huntCmd = &cobra.Command{
 			for _, functionSymbol := range symbolsOrigins.Symbols {
 				syscalls, err := captor.Capture(functionSymbol, captureArgs, opts)
 				if err != nil {
-					fmt.Printf("error capturing syscall: %w", err)
+					fmt.Printf("error capturing syscall: %v", err)
 				}
 
 				saveOpts := writer.WriteOptions{
@@ -94,7 +94,8 @@ func init() {
 	huntCmd.Flags().StringVarP(&harpoonFile, "file", "F", "harpoon-report.yml", "File with the result of analysis")
 	huntCmd.MarkFlagRequired("file")
 
-	huntCmd.Flags().BoolVarP(&commandOutput, "include-cmd-output", "c", false, "Include the executed command output")
+	huntCmd.Flags().BoolVarP(&commandOutput, "include-cmd-stdout", "c", false, "Include the executed command output")
+	huntCmd.Flags().BoolVarP(&commandError, "include-cmd-stderr", "e", false, "Include the executed command error")
 
 	huntCmd.Flags().BoolVarP(&libbpfOutput, "include-libbpf-output", "l", false, "Include the libbpf output")
 

internal/ebpf/probesfacade/captor/capture.go

@@ -31,6 +31,7 @@ type event struct {
 
 type CaptureOptions struct {
 	CommandOutput bool
+	CommandError  bool
 	LibbpfOutput  bool
 }
 
@@ -114,7 +115,9 @@ func Capture(functionSymbol string, cmdArgs []string, opts CaptureOptions) ([]ui
 	// run args that we want to trace
 	var wg sync.WaitGroup
 	wg.Add(1)
-	go executor.Run(cmdArgs, opts.CommandOutput, &wg)
+	outputCh := make(chan string)
+	errorCh := make(chan string)
+	go executor.Run(cmdArgs, opts.CommandOutput, opts.CommandError, &wg, outputCh, errorCh)
 
 	var syscalls []uint32
 	go func() {
@@ -131,6 +134,16 @@ func Capture(functionSymbol string, cmdArgs []string, opts CaptureOptions) ([]ui
 			case lost := <-lostChannel:
 				fmt.Fprintf(os.Stderr, "lost %d data\n", lost)
 				return
+			case line, ok := <-outputCh:
+				if !ok {
+					break
+				}
+				fmt.Println(line)
+			case err, ok := <-errorCh:
+				if !ok {
+					break
+				}
+				fmt.Println(err)
 			}
 		}
 	}()

internal/executor/exec.go

@@ -1,27 +1,50 @@
 package executor
 
 import (
+	"bufio"
 	"fmt"
 	"os/exec"
 	"sync"
 )
 
 // Run execute the command and wait for its end.
 // The cmdOutput argument is used to print the command output.
-func Run(cmd []string, cmdOutput bool, wg *sync.WaitGroup) {
+func Run(cmd []string, cmdOutput, cmdError bool, wg *sync.WaitGroup, outputCh, errorCh chan<- string) {
 	defer func() {
 		wg.Done()
 	}()
 
 	command := exec.Command(cmd[0], cmd[1:]...)
-	output, _ := command.CombinedOutput()
-	if cmdOutput {
-		fmt.Println("----- BEGIN OF COMMAND OUTPUT -----")
-		fmt.Printf("%s", output)
-		fmt.Println("------ END OF COMMAND OUTPUT ------")
-	}
+	stdout, _ := command.StdoutPipe()
+	stderr, _ := command.StderrPipe()
+
+	//command.Wait()
+	command.Start()
+
+	go func() {
+		if cmdOutput {
+			scanner := bufio.NewScanner(stdout)
+			for scanner.Scan() {
+				outputCh <- scanner.Text()
+			}
+			if err := scanner.Err(); err != nil {
+				outputCh <- fmt.Sprintf("error: %v", err)
+			}
+		}
+		if cmdError {
+			scanner := bufio.NewScanner(stderr)
+			for scanner.Scan() {
+				errorCh <- scanner.Text()
+			}
+			if err := scanner.Err(); err != nil {
+				errorCh <- fmt.Sprintf("error: %v", err)
+			}
+		}
+	}()
 
 	command.Wait()
+	close(outputCh)
+	close(errorCh)
 }
 
 func Build(packagePath, outputFile string) (string, error) {