buildinfo.go

package buildinfo

import (
	"encoding/json"
	"fmt"
	"runtime"
)

const (
	infoConcat = "; "
	// infoFmt contains the format used by BuildInfo.Print
	infoFmt = `%s, version %s (branch: %s, revision: %s)
  build user:       %s
  build host:       %s
  build date:       %s
  go version:       %s
  platform:         %s`
)

var (
	GoVersion = runtime.Version()
	GoOS      = runtime.GOOS
	GoArch    = runtime.GOARCH
)

// BuildInfo is a container for version- and environment information
type BuildInfo struct {
	*VersionInfo
	*EnvironmentInfo
}

// NewBuildInfo returns a BuildInfo instance using the provided values
func NewBuildInfo(v *VersionInfo, e *EnvironmentInfo) *BuildInfo {
	return &BuildInfo{
		VersionInfo:     v,
		EnvironmentInfo: e,
	}
}

// New returns a BuildInfo instance with default values
func New() *BuildInfo {
	return NewBuildInfo(NewVersionInfo(), NewEnvironmentInfo())
}

// Parse unmarshals the given JSON byte data into
// a BuildInfo instance. An empty input or even nil
// are considered valid values, and return a default
// instance.
func Parse(info []byte) (result *BuildInfo, err error) {
	result = New()
	if info == nil || len(info) == 0 {
		return
	}

	err = json.Unmarshal(info, result)

	return
}

// TryParse calls Parse and returns a
// default instance in case of an error
func TryParse(info []byte) *BuildInfo {
	result, err := Parse(info)
	if err != nil {
		return New()
	}

	return result
}

// MustParse calls Parse and panics on any error
func MustParse(info []byte) *BuildInfo {
	result, err := Parse(info)
	if err != nil {
		panic(err)
	}

	return result
}

// String returns the Version- and Environment information concatenated
func (i *BuildInfo) String() string {
	return i.VersionInfo.String() + infoConcat + i.EnvironmentInfo.String()
}

// Clone creates an independant copy of itself.
func (i *BuildInfo) Clone() *BuildInfo {
	var (
		i2 *BuildInfo
		v2 *VersionInfo
		e2 *EnvironmentInfo
	)

	if i.VersionInfo != nil {
		v2 = i.VersionInfo.Clone()
	}

	if i.EnvironmentInfo != nil {
		e2 = i.EnvironmentInfo.Clone()
	}

	i2 = &BuildInfo{
		VersionInfo:     v2,
		EnvironmentInfo: e2,
	}

	return i2
}

// Equal compares the fields of this instance to the given one
func (i *BuildInfo) Equal(o *BuildInfo) bool {
	if i == nil || o == nil {
		return i == nil && o == nil
	}

	return i.VersionInfo.Equal(o.VersionInfo) && i.EnvironmentInfo.Equal(o.EnvironmentInfo)
}

// JSON is a wrapper for json.Marshal using the instance as parameter
func (i *BuildInfo) JSON() ([]byte, error) {
	return json.Marshal(i)
}

// Print returns version- and environment information.
func (i *BuildInfo) Print(program string) string {
	v := i.VersionInfo
	if v == nil {
		v = NewVersionInfo()
	}
	e := i.EnvironmentInfo
	if e == nil {
		e = NewEnvironmentInfo()
	}

	return fmt.Sprintf(infoFmt,
		program,
		v.Version,
		v.Branch,
		v.ShortRevision(),
		e.User,
		e.Host,
		e.Date,
		GoVersion,
		GoOS+"/"+GoArch,
	)
}