buildkit/frontend/dockerfile/dockerignore/dockerignore.go

65 lines
1.5 KiB
Go

package dockerignore
import (
"bufio"
"bytes"
"fmt"
"io"
"path/filepath"
"strings"
)
// ReadAll reads a .dockerignore file and returns the list of file patterns
// to ignore. Note this will trim whitespace from each line as well
// as use GO's "clean" func to get the shortest/cleanest path for each.
func ReadAll(reader io.Reader) ([]string, error) {
if reader == nil {
return nil, nil
}
scanner := bufio.NewScanner(reader)
var excludes []string
currentLine := 0
utf8bom := []byte{0xEF, 0xBB, 0xBF}
for scanner.Scan() {
scannedBytes := scanner.Bytes()
// We trim UTF8 BOM
if currentLine == 0 {
scannedBytes = bytes.TrimPrefix(scannedBytes, utf8bom)
}
pattern := string(scannedBytes)
currentLine++
// Lines starting with # (comments) are ignored before processing
if strings.HasPrefix(pattern, "#") {
continue
}
pattern = strings.TrimSpace(pattern)
if pattern == "" {
continue
}
// normalize absolute paths to paths relative to the context
// (taking care of '!' prefix)
invert := pattern[0] == '!'
if invert {
pattern = strings.TrimSpace(pattern[1:])
}
if len(pattern) > 0 {
pattern = filepath.Clean(pattern)
pattern = filepath.ToSlash(pattern)
if len(pattern) > 1 && pattern[0] == '/' {
pattern = pattern[1:]
}
}
if invert {
pattern = "!" + pattern
}
excludes = append(excludes, pattern)
}
if err := scanner.Err(); err != nil {
return nil, fmt.Errorf("Error reading .dockerignore: %v", err)
}
return excludes, nil
}