waitfor-fs

File system resource readiness assertion library for Go. This library extends the waitfor framework to provide file system checking capabilities, allowing you to wait for files and directories to exist before proceeding with your application logic.

Features

• File existence checking: Wait for files to be created or become available
• Directory existence checking: Wait for directories to be created
• Context support: Full support for Go contexts with cancellation and timeouts
• Configurable retries: Use the waitfor framework's built-in retry mechanisms
• Thread-safe: Safe for concurrent use

Installation

go get github.com/go-waitfor/waitfor-fs

Quick Start

package main

import (
	"context"
	"fmt"
	"os"

	"github.com/go-waitfor/waitfor"
	fs "github.com/go-waitfor/waitfor-fs"
)

func main() {
	// Create a waitfor runner with file system support
	runner := waitfor.New(fs.Use())

	// Wait for files and directories to exist
	err := runner.Test(
		context.Background(),
		[]string{"file://./my-file.txt", "file://./my-dir/"},
		waitfor.WithAttempts(5),
	)

	if err != nil {
		fmt.Printf("Files not ready: %v\n", err)
		os.Exit(1)
	}

	fmt.Println("All files are ready!")
}

URL Format

The library uses the file:// URL scheme to specify file system resources:

• Files: file:///absolute/path/to/file.txt or file://./relative/path/file.txt
• Directories: file:///absolute/path/to/directory/ or file://./relative/directory/

Examples

Basic File Checking

package main

import (
	"context"
	"time"

	"github.com/go-waitfor/waitfor"
	fs "github.com/go-waitfor/waitfor-fs"
)

func main() {
	runner := waitfor.New(fs.Use())
	
	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	// Wait for a configuration file to be created
	err := runner.Test(ctx, []string{"file://./config.json"})
	if err != nil {
		panic(err)
	}
}

Multiple Files with Custom Configuration

package main

import (
	"context"
	"time"

	"github.com/go-waitfor/waitfor"
	fs "github.com/go-waitfor/waitfor-fs"
)

func main() {
	runner := waitfor.New(fs.Use())
	
	ctx := context.Background()
	
	// Wait for multiple files with custom retry configuration
	err := runner.Test(
		ctx,
		[]string{
			"file://./data/input.csv",
			"file://./data/schema.json",
			"file://./logs/",
		},
		waitfor.WithAttempts(10),
		waitfor.WithDelay(2*time.Second),
	)
	
	if err != nil {
		panic(err)
	}
}

Using the Resource Directly

package main

import (
	"context"
	"net/url"

	fs "github.com/go-waitfor/waitfor-fs"
)

func main() {
	// Parse the file URL
	u, err := url.Parse("file://./important-file.txt")
	if err != nil {
		panic(err)
	}

	// Create the file resource
	resource, err := fs.New(u)
	if err != nil {
		panic(err)
	}

	// Test if the file exists
	ctx := context.Background()
	err = resource.Test(ctx)
	if err != nil {
		panic(err)
	}
}

API Reference

func Use() waitfor.ResourceConfig

Returns a resource configuration for the waitfor framework that enables file system checking with the file scheme.

func New(u *url.URL) (waitfor.Resource, error)

Creates a new file system resource from a URL. The URL must use the file scheme.

Parameters:

• u: A URL with the file scheme pointing to a file or directory

Returns:

• A waitfor.Resource that can be used to test file existence
• An error if the URL is invalid or nil

func (*File) Test(ctx context.Context) error

Tests whether the file or directory exists. This method is called by the waitfor framework during resource checking.

Parameters:

• ctx: Context for cancellation and timeout control

Returns:

• nil if the file or directory exists
• An error if the file doesn't exist, the context is cancelled, or there's a file system error

About waitfor

This library is part of the waitfor ecosystem, which provides a unified framework for waiting on various types of resources to become ready. Other available waitfor plugins include:

• HTTP endpoints
• Database connections
• Network services
• And more...

Requirements

• Go 1.23 or later

License

This project is licensed under the Apache License 2.0 - see the LICENSE file for details.