shell.go

// Copyright 2019 Drone.IO Inc. All rights reserved.
// Use of this source code is governed by the Polyform License
// that can be found in the LICENSE file.

// Package shell provides functions for converting shell commands
// to posix shell scripts.
package shell

import (
	"bytes"
	"fmt"
	"strings"
)

// Script converts a slice of individual shell commands to
// a posix-compliant shell script.
func Script(commands []string) string {
	buf := new(bytes.Buffer)
	fmt.Fprintln(buf)
	fmt.Fprintf(buf, optionScript)
	fmt.Fprintln(buf)
	for _, command := range commands {
		escaped := fmt.Sprintf("%q", command)
		escaped = strings.Replace(escaped, "$", `\$`, -1)
		buf.WriteString(fmt.Sprintf(
			traceScript,
			escaped,
			command,
		))
	}
	return buf.String()
}

// optionScript is a helper script this is added to the build
// to set shell options, in this case, to exit on error.
const optionScript = `
if [ ! -z "${DRONE_NETRC_FILE}" ]; then
	echo $DRONE_NETRC_FILE > $HOME/.netrc
	chmod 600 $HOME/.netrc
fi

unset DRONE_SCRIPT
unset DRONE_NETRC_MACHINE
unset DRONE_NETRC_USERNAME
unset DRONE_NETRC_PASSWORD
unset DRONE_NETRC_FILE

set -e
`

// traceScript is a helper script that is added to
// the build script to trace a command.
const traceScript = `
echo + %s
%s
`