builder/parse.go

// Copyright (c) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License.

package builder

import (
	"regexp"
	"strings"

	"github.com/Azure/acr-builder/util"
)

var httpPrefix = regexp.MustCompile("^https?://")
var gitURLWithSuffix = regexp.MustCompile(`\.git(?:#.+)?$`)

const (
	azureDevOpsHost = "dev.azure.com"
	vstsHost        = ".visualstudio.com"
)

// parseDockerBuildCmd parses a docker build command and extracts the
// context, target and Dockerfile from it.
func parseDockerBuildCmd(cmd string) (dockerfile string, target string, context string) {
	fields := strings.Fields(cmd)
	prev := ""
	dockerfile = ""
	context = "."
	target = ""

	for i := 0; i < len(fields); i++ {
		v := fields[i]

		// trim quotes on all docker build command args
		if prev == "-f" || prev == "--file" {
			dockerfile = util.TrimQuotes(v)
		} else if prev == "--target" {
			target = util.TrimQuotes(v)
		} else if !strings.HasPrefix(prev, "-") && !strings.HasPrefix(v, "-") {
			context = util.TrimQuotes(v)
		}

		prev = v
	}

	return dockerfile, target, context
}

// replacePositionalContext parses the specified command for its positional context
// and replaces it if one's found. Returns the modified command after replacement.
func replacePositionalContext(runCmd string, replacement string) string {
	fields := strings.Fields(runCmd)
	prev := ""

	for i := 0; i < len(fields); i++ {
		if !strings.HasPrefix(prev, "-") && !strings.HasPrefix(fields[i], "-") {
			fields[i] = replacement
			return strings.Join(fields, " ")
		}
		prev = fields[i]
	}

	return runCmd
}

func getContextFromGitURL(gitURL string) string {
	lower := strings.ToLower(gitURL)
	if httpPrefix.MatchString(gitURL) &&
		(strings.Contains(lower, vstsHost) ||
			gitURLWithSuffix.MatchString(gitURL) ||
			strings.Contains(lower, azureDevOpsHost)) {
		pos := strings.LastIndex(gitURL, "#")
		if pos >= 0 {
			frag := gitURL[pos+1:]
			splits := strings.Split(frag, ":")
			if len(splits) >= 2 {
				return splits[1]
			}
		}
	}
	return "."
}