Merge pull request #190 from ThinkMo/main

Adds support for append feature to function  capture_local

docs/README.md

@@ -480,6 +480,7 @@ This function runs a command locally on the machine running the script.  It then
 | `workdir`|A parent directory where captured files will be saved|No, defaults to `crashd_config.workdir`|
 | `file_name`|The path/name of the generated file|No, auto-generated based on command string, if omitted|
 | `desc`|A short description added at the start of the file|No|
+| `append` | boolean indicator to append to a file if it already exists or not |No, defaults to `False`|
 
 #### Output
 `capture_local()` returns the full path of the capured output file.
@@ -767,4 +768,4 @@ bloop blah
 # this will result in a warning message with foo=bar as the only pair pairs to be passed to the .crsh file
 $ crash run diagnsotics.crsh --args-file /tmp/script.args
 WARN[0000] unknown entry in args file: blooop blah
-```
+```

starlark/capture.go

@@ -163,26 +163,33 @@ func execCaptureSSH(host, cmdStr, rootDir, fileName, desc string, agent ssh.Agen
 	reader, err := ssh.RunRead(args, agent, cmdStr)
 	if err != nil {
 		logrus.Errorf("%s failed: %s", identifiers.capture, err)
-		if err := captureOutput(strings.NewReader(err.Error()), filePath, fmt.Sprintf("%s: failed", cmdStr)); err != nil {
+		if err := captureOutput(strings.NewReader(err.Error()), filePath, fmt.Sprintf("%s: failed", cmdStr), false); err != nil {
 			logrus.Errorf("%s output failed: %s", identifiers.capture, err)
 			return commandResult{resource: args.Host, result: filePath, err: err}, err
 		}
 	}
 
-	if err := captureOutput(reader, filePath, desc); err != nil {
+	if err := captureOutput(reader, filePath, desc, false); err != nil {
 		logrus.Errorf("%s output failed: %s", identifiers.capture, err)
 		return commandResult{resource: args.Host, result: filePath, err: err}, err
 	}
 
 	return commandResult{resource: args.Host, result: filePath, err: err}, nil
 }
 
-func captureOutput(source io.Reader, filePath, desc string) error {
+func captureOutput(source io.Reader, filePath, desc string, append bool) error {
 	if source == nil {
 		return fmt.Errorf("source reader is nill")
 	}
 
-	file, err := os.Create(filePath)
+	flag := os.O_CREATE | os.O_WRONLY
+	if append {
+		flag |= os.O_APPEND
+	} else {
+		flag |= os.O_TRUNC
+	}
+
+	file, err := os.OpenFile(filePath, flag, 0644)
 	if err != nil {
 		return err
 	}

starlark/capture_local.go

@@ -14,15 +14,17 @@ import (
 
 // captureLocalFunc is a built-in starlark function that runs a provided command on the local machine.
 // The output of the command is stored in a file at a specified location under the workdir directory.
-// Starlark format: run_local(cmd=<command> [,workdir=path][,file_name=name][,desc=description])
+// Starlark format: run_local(cmd=<command> [,workdir=path][,file_name=name][,desc=description][,append=append])
 func captureLocalFunc(thread *starlark.Thread, b *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) {
 	var cmdStr, workdir, fileName, desc string
+	var append bool
 	if err := starlark.UnpackArgs(
 		identifiers.captureLocal, args, kwargs,
 		"cmd", &cmdStr,
 		"workdir?", &workdir,
 		"file_name?", &fileName,
 		"desc?", &desc,
+		"append?", &append,
 	); err != nil {
 		return starlark.None, fmt.Errorf("%s: %s", identifiers.captureLocal, err)
 	}
@@ -48,7 +50,7 @@ func captureLocalFunc(thread *starlark.Thread, b *starlark.Builtin, args starlar
 		return starlark.None, fmt.Errorf("%s: %s", identifiers.captureLocal, p.Err())
 	}
 
-	if err := captureOutput(p.Out(), filePath, desc); err != nil {
+	if err := captureOutput(p.Out(), filePath, desc, append); err != nil {
 		return starlark.None, fmt.Errorf("%s: %s", identifiers.captureLocal, err)
 	}
 

starlark/capture_local_test.go

@@ -70,14 +70,29 @@ func TestCaptureLocalFunc(t *testing.T) {
 					{starlark.String("workdir"), starlark.String("/tmp/capturecrashd")},
 					{starlark.String("file_name"), starlark.String("echo.txt")},
 					{starlark.String("desc"), starlark.String("echo command")},
+					{starlark.String("append"), starlark.True},
 				}
 			},
 			eval: func(t *testing.T, kwargs []starlark.Tuple) {
+				expected := filepath.Join("/tmp/capturecrashd", "echo.txt")
+				err := os.MkdirAll("/tmp/capturecrashd", 0777)
+				if err != nil {
+					t.Fatal(err)
+				}
+				f, err := os.OpenFile(expected, os.O_RDWR|os.O_CREATE, 0644)
+				if err != nil {
+					t.Fatal(err)
+				}
+				if _, err := f.Write([]byte("Hello World!\n")); err != nil {
+					t.Fatal(err)
+				}
+				if err := f.Close(); err != nil {
+					t.Fatal(err)
+				}
 				val, err := captureLocalFunc(newTestThreadLocal(t), nil, nil, kwargs)
 				if err != nil {
 					t.Fatal(err)
 				}
-				expected := filepath.Join("/tmp/capturecrashd", "echo.txt")
 				result := ""
 				if r, ok := val.(starlark.String); ok {
 					result = string(r)
@@ -100,7 +115,7 @@ func TestCaptureLocalFunc(t *testing.T) {
 					t.Fatal(err)
 				}
 				expected = strings.TrimSpace(buf.String())
-				if expected != "echo command\nHello World!" {
+				if expected != "Hello World!\necho command\nHello World!" {
 					t.Errorf("unexpected content captured: %s", expected)
 				}
 				if err := file.Close(); err != nil {
@@ -174,15 +189,29 @@ result = capture_local("echo 'Hello World!'")
 		{
 			name: "capture local with args",
 			script: `
-result = capture_local(cmd="echo 'Hello World!'", workdir="/tmp/capturecrash", file_name="echo_out.txt", desc="output command")
+result = capture_local(cmd="echo 'Hello World!'", workdir="/tmp/capturecrash", file_name="echo_out.txt", desc="output command", append=True)
 `,
 			eval: func(t *testing.T, script string) {
+				expected := filepath.Join("/tmp/capturecrash", "echo_out.txt")
+				err := os.MkdirAll("/tmp/capturecrash", 0777)
+				if err != nil {
+					t.Fatal(err)
+				}
+				f, err := os.OpenFile(expected, os.O_RDWR|os.O_CREATE, 0644)
+				if err != nil {
+					t.Fatal(err)
+				}
+				if _, err := f.Write([]byte("Hello World!\n")); err != nil {
+					t.Fatal(err)
+				}
+				if err := f.Close(); err != nil {
+					t.Fatal(err)
+				}
 				exe := New()
 				if err := exe.Exec("test.star", strings.NewReader(script)); err != nil {
 					t.Fatal(err)
 				}
 
-				expected := filepath.Join("/tmp/capturecrash", "echo_out.txt")
 				var result string
 				resultVal := exe.result["result"]
 				if resultVal == nil {
@@ -211,7 +240,7 @@ result = capture_local(cmd="echo 'Hello World!'", workdir="/tmp/capturecrash", f
 					t.Fatal(err)
 				}
 				expected = strings.TrimSpace(buf.String())
-				if expected != "output command\nHello World!" {
+				if expected != "Hello World!\noutput command\nHello World!" {
 					t.Errorf("unexpected content captured: %s", expected)
 				}
 				if err := file.Close(); err != nil {