📁 File System

pkg/composerutils/fs.go provides basic file system utility functions, reused by pkg/composer, pkg/installer, and other modules.

Function List

Function	Signature	Description
CheckWritePermission	(dir string) error	Check directory writable (create if not exists)
EnsureDirectoryExists	(dir string) error	Ensure directory exists, create recursively if not
CreateFileWithContent	(filePath string, content []byte, perm os.FileMode) error	Create file and write content

CheckWritePermission

Checks if a directory has write permission. If the directory doesn't exist, it will first attempt to create it, then verify write permission by creating a temporary file, and automatically clean up after testing.

func CheckWritePermission(dir string) error

Parameter	Type	Description
dir	string	Directory path to check

Possible errors: Directory creation failed, no write permission.

if err := composerutils.CheckWritePermission("/usr/local/bin"); err != nil {
    log.Fatalf("Directory has no write permission: %v", err)
}

EnsureDirectoryExists

Ensures specified directory exists, creates recursively if not (permission 0755).

func EnsureDirectoryExists(dir string) error

installDir := "/opt/composer-skills"
if err := composerutils.EnsureDirectoryExists(installDir); err != nil {
    log.Fatalf("Unable to create installation directory: %v", err)
}

CreateFileWithContent

Creates file at specified path and writes content, automatically ensuring parent directory exists.

func CreateFileWithContent(filePath string, content []byte, perm os.FileMode) error

Parameter	Type	Description
filePath	string	File path (including filename)
content	[]byte	Content to write
perm	os.FileMode	File permission (e.g., 0644, 0755)

script := []byte("#!/bin/sh\necho 'Hello World'")
if err := composerutils.CreateFileWithContent("/usr/local/bin/hello.sh", script, 0755); err != nil {
    log.Fatalf("Unable to create script: %v", err)
}

Relationship with standard library

These three functions are thin wrappers around os.MkdirAll, os.WriteFile, os.Create, adding combined semantics like "ensure parent directory exists" and "write permission detection", avoiding repetitive handling.

Advanced

• For mocking file system operations in tests, see Mock Interfaces MockFileSystemHelper.
• Test file assertions see Test Utilities.