HW8 is completed

hw08_envdir_tool/env_reader.go

@@ -1,10 +1,79 @@
 package main
 
+import (
+	"errors"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+	"unicode"
+)
+
 type Environment map[string]string
 
-// ReadDir reads a specified directory and returns map of env variables.
-// Variables represented as files where filename is name of variable, file first line is a value.
 func ReadDir(dir string) (Environment, error) {
-	// Place your code here
-	return nil, nil
+	// ReadDir reads a specified directory and returns map of env variables.
+	// Variables represented as files where filename is name of variable, file first line is a value.
+	env := make(Environment)
+	dataDir, err := ioutil.ReadDir(dir)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, d := range dataDir {
+		fileName := d.Name()
+
+		// skip recursive directory search and files with "="
+		if d.IsDir() || strings.Contains(fileName, "=") {
+			continue
+		}
+
+		filePath := filepath.Join(dir, fileName)
+		val, err := readFileValue(filePath)
+		// skip file with error
+		if err != nil {
+			continue
+		}
+		env[fileName] = val
+	}
+
+	return env, nil
+}
+
+func readFileValue(filePath string) (string, error) {
+	// function read file and return first "trail trimmed" string
+	r, err := os.Open(filePath)
+	if err != nil {
+		return "", err
+	}
+	defer r.Close()
+
+	st, err := r.Stat()
+	if err != nil {
+		return "", err
+	}
+
+	// don't read empty files
+	if st.Size() <= 0 {
+		return "", nil
+	}
+
+	bytes, err := ioutil.ReadAll(r)
+	if err != nil {
+		return "", err
+	}
+
+	// read only first line if it doesn't not empty
+	for _, val := range strings.Split(string(bytes), "\n") {
+		if val == "" {
+			continue
+		}
+
+		// convering 0x00 to \n magic
+		val = strings.ReplaceAll(val, string('\x00'), "\n")
+
+		return strings.TrimRightFunc(val, unicode.IsSpace), nil
+	}
+
+	return "", errors.New("empty result")
 }

hw08_envdir_tool/env_reader_test.go

@@ -1,7 +1,47 @@
 package main
 
-import "testing"
+import (
+	"fmt"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestReadFileValue(t *testing.T) {
+	t.Run("not exist file", func(t *testing.T) {
+		_, err := readFileValue("testdata/env/not-exist")
+		require.True(t, os.IsNotExist(err))
+	})
+
+	t.Run("empty file", func(t *testing.T) {
+		val, err := readFileValue("testdata/env/UNSET")
+		require.Nil(t, err)
+		require.Equal(t, "", val)
+	})
+
+	t.Run("heavy variable", func(t *testing.T) {
+		sample := fmt.Sprintf("   foo\nwith new line")
+
+		val, err := readFileValue("testdata/env/FOO")
+		require.Nil(t, err)
+		require.Equal(t, sample, val)
+	})
+}
 
 func TestReadDir(t *testing.T) {
-	// Place your code here
+	t.Run("not exist dir", func(t *testing.T) {
+		_, err := ReadDir("testdata/env-not-exist")
+		err, ok := err.(*os.PathError)
+
+		require.True(t, ok)
+		require.NotNil(t, err)
+	})
+
+	t.Run("complex parse check", func(t *testing.T) {
+		envMap, err := ReadDir("testdata/env")
+		require.Nil(t, err)
+
+		require.Equal(t, envMap, Environment{"UNSET": "", "BAR": "bar", "HELLO": "\"hello\"", "FOO": "   foo\nwith new line"})
+	})
 }

hw08_envdir_tool/executor.go

@@ -1,7 +1,38 @@
 package main
 
-// RunCmd runs a command + arguments (cmd) with environment variables from env
+import (
+	"fmt"
+	"os/exec"
+)
+
 func RunCmd(cmd []string, env Environment) (returnCode int) {
-	// Place your code here
-	return
+	// RunCmd runs a command + arguments (cmd) with environment variables from env
+
+	execEnv := make([]string, len(env))
+	for envVariable, value := range env {
+		// skip empty values
+		if value == "" {
+			continue
+		}
+		execEnv = append(execEnv, fmt.Sprintf("%s=%s", envVariable, value))
+	}
+
+	command, args := cmd[0], cmd[1:]
+	cmdExec := exec.Command(command, args...)
+	cmdExec.Env = execEnv
+
+	stdoutStderr, err := cmdExec.CombinedOutput()
+	if err != nil {
+		exitError, ok := err.(*exec.ExitError)
+		if ok {
+			return exitError.ExitCode()
+		}
+
+		// os.PathError and other non caugth errors
+		return 1
+	}
+
+	fmt.Printf("%s", stdoutStderr)
+
+	return 0
 }

hw08_envdir_tool/executor_test.go

@@ -1,7 +1,31 @@
 package main
 
-import "testing"
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
 
 func TestRunCmd(t *testing.T) {
-	// Place your code here
+	t.Run("not exist file", func(t *testing.T) {
+		exitCode := RunCmd([]string{"not-exist-command"}, nil)
+		require.EqualValues(t, 1, exitCode)
+	})
+
+	t.Run("check output", func(t *testing.T) {
+		r, w, err := os.Pipe()
+		require.Nil(t, err)
+
+		os.Stdout = w
+		exitCode := RunCmd([]string{"echo", "-n", "test"}, nil)
+		w.Close()
+
+		require.EqualValues(t, 0, exitCode)
+		out, err := ioutil.ReadAll(r)
+		require.Nil(t, err)
+
+		require.Equal(t, "test", string(out))
+	})
 }

hw08_envdir_tool/go.mod

@@ -1,3 +1,5 @@
-module github.com/fixme_my_friend/hw08_envdir_tool
+module github.com/ezhk/golang-learning/hw08_envdir_tool
 
 go 1.14
+
+require github.com/stretchr/testify v1.6.1

hw08_envdir_tool/main.go

@@ -1,5 +1,16 @@
 package main
 
+import (
+	"os"
+)
+
 func main() {
-	// Place your code here
+	envDir, cmd := os.Args[1], os.Args[2:]
+	environment, err := ReadDir(envDir)
+	if err != nil {
+		os.Exit(1)
+	}
+
+	exitCode := RunCmd(cmd, environment)
+	os.Exit(exitCode)
 }