pkg/parsers/parsers.go

// Package parsers provides helper functions to parse and validate different type
// of string. It can be hosts, unix addresses, tcp addresses, filters, kernel
// operating system versions.
package parsers

import (
	"fmt"
	"net"
	"net/url"
	"path"
	"runtime"
	"strconv"
	"strings"
)

// ParseDockerDaemonHost parses the specified address and returns an address that will be used as the host.
// Depending of the address specified, will use the defaultTCPAddr or defaultUnixAddr
// defaultUnixAddr must be a absolute file path (no `unix://` prefix)
// defaultTCPAddr must be the full `tcp://host:port` form
func ParseDockerDaemonHost(defaultTCPAddr, defaultTLSHost, defaultUnixAddr, defaultAddr, addr string) (string, error) {
	addr = strings.TrimSpace(addr)
	if addr == "" {
		if defaultAddr == defaultTLSHost {
			return defaultTLSHost, nil
		}
		if runtime.GOOS != "windows" {
			return fmt.Sprintf("unix://%s", defaultUnixAddr), nil
		}
		return defaultTCPAddr, nil
	}
	addrParts := strings.Split(addr, "://")
	if len(addrParts) == 1 {
		addrParts = []string{"tcp", addrParts[0]}
	}

	switch addrParts[0] {
	case "tcp":
		return ParseTCPAddr(addrParts[1], defaultTCPAddr)
	case "unix":
		return ParseUnixAddr(addrParts[1], defaultUnixAddr)
	case "fd":
		return addr, nil
	default:
		return "", fmt.Errorf("Invalid bind address format: %s", addr)
	}
}

// ParseUnixAddr parses and validates that the specified address is a valid UNIX
// socket address. It returns a formatted UNIX socket address, either using the
// address parsed from addr, or the contents of defaultAddr if addr is a blank
// string.
func ParseUnixAddr(addr string, defaultAddr string) (string, error) {
	addr = strings.TrimPrefix(addr, "unix://")
	if strings.Contains(addr, "://") {
		return "", fmt.Errorf("Invalid proto, expected unix: %s", addr)
	}
	if addr == "" {
		addr = defaultAddr
	}
	return fmt.Sprintf("unix://%s", addr), nil
}

// ParseTCPAddr parses and validates that the specified address is a valid TCP
// address. It returns a formatted TCP address, either using the address parsed
// from tryAddr, or the contents of defaultAddr if tryAddr is a blank string.
// tryAddr is expected to have already been Trim()'d
// defaultAddr must be in the full `tcp://host:port` form
func ParseTCPAddr(tryAddr string, defaultAddr string) (string, error) {
	if tryAddr == "" || tryAddr == "tcp://" {
		return defaultAddr, nil
	}
	addr := strings.TrimPrefix(tryAddr, "tcp://")
	if strings.Contains(addr, "://") || addr == "" {
		return "", fmt.Errorf("Invalid proto, expected tcp: %s", tryAddr)
	}

	defaultAddr = strings.TrimPrefix(defaultAddr, "tcp://")
	defaultHost, defaultPort, err := net.SplitHostPort(defaultAddr)
	if err != nil {
		return "", err
	}
	// url.Parse fails for trailing colon on IPv6 brackets on Go 1.5, but
	// not 1.4. See https://github.com/golang/go/issues/12200 and
	// https://github.com/golang/go/issues/6530.
	if strings.HasSuffix(addr, "]:") {
		addr += defaultPort
	}

	u, err := url.Parse("tcp://" + addr)
	if err != nil {
		return "", err
	}

	host, port, err := net.SplitHostPort(u.Host)
	if err != nil {
		return "", fmt.Errorf("Invalid bind address format: %s", tryAddr)
	}

	if host == "" {
		host = defaultHost
	}
	if port == "" {
		port = defaultPort
	}
	p, err := strconv.Atoi(port)
	if err != nil && p == 0 {
		return "", fmt.Errorf("Invalid bind address format: %s", tryAddr)
	}

	return fmt.Sprintf("tcp://%s%s", net.JoinHostPort(host, port), u.Path), nil
}

// PartParser parses and validates the specified string (data) using the specified template
// e.g. ip:public:private -> 192.168.0.1:80:8000
func PartParser(template, data string) (map[string]string, error) {
	// ip:public:private
	var (
		templateParts = strings.Split(template, ":")
		parts         = strings.Split(data, ":")
		out           = make(map[string]string, len(templateParts))
	)
	if len(parts) != len(templateParts) {
		return nil, fmt.Errorf("Invalid format to parse. %s should match template %s", data, template)
	}

	for i, t := range templateParts {
		value := ""
		if len(parts) > i {
			value = parts[i]
		}
		out[t] = value
	}
	return out, nil
}

// ParseKeyValueOpt parses and validates the specified string as a key/value pair (key=value)
func ParseKeyValueOpt(opt string) (string, string, error) {
	parts := strings.SplitN(opt, "=", 2)
	if len(parts) != 2 {
		return "", "", fmt.Errorf("Unable to parse key/value option: %s", opt)
	}
	return strings.TrimSpace(parts[0]), strings.TrimSpace(parts[1]), nil
}

// ParsePortRange parses and validates the specified string as a port-range (8000-9000)
func ParsePortRange(ports string) (uint64, uint64, error) {
	if ports == "" {
		return 0, 0, fmt.Errorf("Empty string specified for ports.")
	}
	if !strings.Contains(ports, "-") {
		start, err := strconv.ParseUint(ports, 10, 16)
		end := start
		return start, end, err
	}

	parts := strings.Split(ports, "-")
	start, err := strconv.ParseUint(parts[0], 10, 16)
	if err != nil {
		return 0, 0, err
	}
	end, err := strconv.ParseUint(parts[1], 10, 16)
	if err != nil {
		return 0, 0, err
	}
	if end < start {
		return 0, 0, fmt.Errorf("Invalid range specified for the Port: %s", ports)
	}
	return start, end, nil
}

// ParseLink parses and validates the specified string as a link format (name:alias)
func ParseLink(val string) (string, string, error) {
	if val == "" {
		return "", "", fmt.Errorf("empty string specified for links")
	}
	arr := strings.Split(val, ":")
	if len(arr) > 2 {
		return "", "", fmt.Errorf("bad format for links: %s", val)
	}
	if len(arr) == 1 {
		return val, val, nil
	}
	// This is kept because we can actually get an HostConfig with links
	// from an already created container and the format is not `foo:bar`
	// but `/foo:/c1/bar`
	if strings.HasPrefix(arr[0], "/") {
		_, alias := path.Split(arr[1])
		return arr[0][1:], alias, nil
	}
	return arr[0], arr[1], nil
}

// ParseUintList parses and validates the specified string as the value
// found in some cgroup file (e.g. `cpuset.cpus`, `cpuset.mems`), which could be
// one of the formats below. Note that duplicates are actually allowed in the
// input string. It returns a `map[int]bool` with available elements from `val`
// set to `true`.
// Supported formats:
//     7
//     1-6
//     0,3-4,7,8-10
//     0-0,0,1-7
//     03,1-3      <- this is gonna get parsed as [1,2,3]
//     3,2,1
//     0-2,3,1
func ParseUintList(val string) (map[int]bool, error) {
	if val == "" {
		return map[int]bool{}, nil
	}

	availableInts := make(map[int]bool)
	split := strings.Split(val, ",")
	errInvalidFormat := fmt.Errorf("invalid format: %s", val)

	for _, r := range split {
		if !strings.Contains(r, "-") {
			v, err := strconv.Atoi(r)
			if err != nil {
				return nil, errInvalidFormat
			}
			availableInts[v] = true
		} else {
			split := strings.SplitN(r, "-", 2)
			min, err := strconv.Atoi(split[0])
			if err != nil {
				return nil, errInvalidFormat
			}
			max, err := strconv.Atoi(split[1])
			if err != nil {
				return nil, errInvalidFormat
			}
			if max < min {
				return nil, errInvalidFormat
			}
			for i := min; i <= max; i++ {
				availableInts[i] = true
			}
		}
	}
	return availableInts, nil
}