Engine: break out Env utilities into their own type - Env

engine/engine.go

@@ -111,6 +111,7 @@ func (eng *Engine) Job(name string, args ...string) *Job {
 		Stdin:  NewInput(),
 		Stdout: NewOutput(),
 		Stderr: NewOutput(),
+		env:    &Env{},
 	}
 	job.Stdout.Add(utils.NopWriteCloser(eng.Stdout))
 	job.Stderr.Add(utils.NopWriteCloser(eng.Stderr))

engine/env.go

@@ -0,0 +1,221 @@
+package engine
+
+import (
+	"strings"
+	"io"
+	"encoding/json"
+	"strconv"
+	"bytes"
+	"fmt"
+)
+
+type Env []string
+
+
+func (env *Env) Get(key string) (value string) {
+	// FIXME: use Map()
+	for _, kv := range *env {
+		if strings.Index(kv, "=") == -1 {
+			continue
+		}
+		parts := strings.SplitN(kv, "=", 2)
+		if parts[0] != key {
+			continue
+		}
+		if len(parts) < 2 {
+			value = ""
+		} else {
+			value = parts[1]
+		}
+	}
+	return
+}
+
+func (env *Env) Exists(key string) bool {
+	_, exists := env.Map()[key]
+	return exists
+}
+
+func (env *Env) GetBool(key string) (value bool) {
+	s := strings.ToLower(strings.Trim(env.Get(key), " \t"))
+	if s == "" || s == "0" || s == "no" || s == "false" || s == "none" {
+		return false
+	}
+	return true
+}
+
+
+func (env *Env) SetBool(key string, value bool) {
+	if value {
+		env.Set(key, "1")
+	} else {
+		env.Set(key, "0")
+	}
+}
+
+func (env *Env) GetInt(key string) int64 {
+	s := strings.Trim(env.Get(key), " \t")
+	val, err := strconv.ParseInt(s, 10, 64)
+	if err != nil {
+		return -1
+	}
+	return val
+}
+
+func (env *Env) SetInt(key string, value int64) {
+	env.Set(key, fmt.Sprintf("%d", value))
+}
+
+// Returns nil if key not found
+func (env *Env) GetList(key string) []string {
+	sval := env.Get(key)
+	if sval == "" {
+		return nil
+	}
+	l := make([]string, 0, 1)
+	if err := json.Unmarshal([]byte(sval), &l); err != nil {
+		l = append(l, sval)
+	}
+	return l
+}
+
+func (env *Env) SetJson(key string, value interface{}) error {
+	sval, err := json.Marshal(value)
+	if err != nil {
+		return err
+	}
+	env.Set(key, string(sval))
+	return nil
+}
+
+func (env *Env) SetList(key string, value []string) error {
+	return env.SetJson(key, value)
+}
+
+func (env *Env) Set(key, value string) {
+	*env = append(*env, key+"="+value)
+}
+
+func NewDecoder(src io.Reader) *Decoder {
+	return &Decoder{
+		json.NewDecoder(src),
+	}
+}
+
+type Decoder struct {
+	*json.Decoder
+}
+
+func (decoder *Decoder) Decode() (*Env, error) {
+	m := make(map[string]interface{})
+	if err := decoder.Decoder.Decode(&m); err != nil {
+		return nil, err
+	}
+	env := &Env{}
+	for key, value := range m {
+		env.SetAuto(key, value)
+	}
+	return env, nil
+}
+
+// DecodeEnv decodes `src` as a json dictionary, and adds
+// each decoded key-value pair to the environment.
+//
+// If `src` cannot be decoded as a json dictionary, an error
+// is returned.
+func (env *Env) Decode(src io.Reader) error {
+	m := make(map[string]interface{})
+	if err := json.NewDecoder(src).Decode(&m); err != nil {
+		return err
+	}
+	for k, v := range m {
+		env.SetAuto(k, v)
+	}
+	return nil
+}
+
+func (env *Env) SetAuto(k string, v interface{}) {
+	// FIXME: we fix-convert float values to int, because
+	// encoding/json decodes integers to float64, but cannot encode them back.
+	// (See http://golang.org/src/pkg/encoding/json/decode.go#L46)
+	if fval, ok := v.(float64); ok {
+		env.SetInt(k, int64(fval))
+	} else if sval, ok := v.(string); ok {
+		env.Set(k, sval)
+	} else if val, err := json.Marshal(v); err == nil {
+		env.Set(k, string(val))
+	} else {
+		env.Set(k, fmt.Sprintf("%v", v))
+	}
+}
+
+func (env *Env) Encode(dst io.Writer) error {
+	m := make(map[string]interface{})
+	for k, v := range env.Map() {
+		var val interface{}
+		if err := json.Unmarshal([]byte(v), &val); err == nil {
+			// FIXME: we fix-convert float values to int, because
+			// encoding/json decodes integers to float64, but cannot encode them back.
+			// (See http://golang.org/src/pkg/encoding/json/decode.go#L46)
+			if fval, isFloat := val.(float64); isFloat {
+				val = int(fval)
+			}
+			m[k] = val
+		} else {
+			m[k] = v
+		}
+	}
+	if err := json.NewEncoder(dst).Encode(&m); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (env *Env) WriteTo(dst io.Writer) (n int64, err error) {
+	// FIXME: return the number of bytes written to respect io.WriterTo
+	return 0, env.Encode(dst)
+}
+
+func (env *Env) Export(dst interface{}) (err error) {
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("ExportEnv %s", err)
+		}
+	}()
+	var buf bytes.Buffer
+	// step 1: encode/marshal the env to an intermediary json representation
+	if err := env.Encode(&buf); err != nil {
+		return err
+	}
+	// step 2: decode/unmarshal the intermediary json into the destination object
+	if err := json.NewDecoder(&buf).Decode(dst); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (env *Env) Import(src interface{}) (err error) {
+	defer func() {
+		if err != nil {
+			err = fmt.Errorf("ImportEnv: %s", err)
+		}
+	}()
+	var buf bytes.Buffer
+	if err := json.NewEncoder(&buf).Encode(src); err != nil {
+		return err
+	}
+	if err := env.Decode(&buf); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (env *Env) Map() map[string]string {
+	m := make(map[string]string)
+	for _, kv := range *env {
+		parts := strings.SplitN(kv, "=", 2)
+		m[parts[0]] = parts[1]
+	}
+	return m
+}
+

engine/job.go

@@ -1,11 +1,8 @@
 package engine
 
 import (
-	"bytes"
-	"encoding/json"
 	"fmt"
 	"io"
-	"strconv"
 	"strings"
 	"time"
 )
@@ -27,7 +24,7 @@ type Job struct {
 	Eng     *Engine
 	Name    string
 	Args    []string
-	env     []string
+	env	*Env
 	Stdout  *Output
 	Stderr  *Output
 	Stdin   *Input
@@ -105,80 +102,40 @@ func (job *Job) String() string {
 }
 
 func (job *Job) Getenv(key string) (value string) {
-	for _, kv := range job.env {
-		if strings.Index(kv, "=") == -1 {
-			continue
-		}
-		parts := strings.SplitN(kv, "=", 2)
-		if parts[0] != key {
-			continue
-		}
-		if len(parts) < 2 {
-			value = ""
-		} else {
-			value = parts[1]
-		}
-	}
-	return
+	return job.env.Get(key)
 }
 
 func (job *Job) GetenvBool(key string) (value bool) {
-	s := strings.ToLower(strings.Trim(job.Getenv(key), " \t"))
-	if s == "" || s == "0" || s == "no" || s == "false" || s == "none" {
-		return false
-	}
-	return true
+	return job.env.GetBool(key)
 }
 
 func (job *Job) SetenvBool(key string, value bool) {
-	if value {
-		job.Setenv(key, "1")
-	} else {
-		job.Setenv(key, "0")
-	}
+	job.env.SetBool(key, value)
 }
 
 func (job *Job) GetenvInt(key string) int64 {
-	s := strings.Trim(job.Getenv(key), " \t")
-	val, err := strconv.ParseInt(s, 10, 64)
-	if err != nil {
-		return -1
-	}
-	return val
+	return job.env.GetInt(key)
 }
 
 func (job *Job) SetenvInt(key string, value int64) {
-	job.Setenv(key, fmt.Sprintf("%d", value))
+	job.env.SetInt(key, value)
 }
 
 // Returns nil if key not found
 func (job *Job) GetenvList(key string) []string {
-	sval := job.Getenv(key)
-	if sval == "" {
-		return nil
-	}
-	l := make([]string, 0, 1)
-	if err := json.Unmarshal([]byte(sval), &l); err != nil {
-		l = append(l, sval)
-	}
-	return l
+	return job.env.GetList(key)
 }
 
 func (job *Job) SetenvJson(key string, value interface{}) error {
-	sval, err := json.Marshal(value)
-	if err != nil {
-		return err
-	}
-	job.Setenv(key, string(sval))
-	return nil
+	return job.env.SetJson(key, value)
 }
 
 func (job *Job) SetenvList(key string, value []string) error {
-	return job.SetenvJson(key, value)
+	return job.env.SetJson(key, value)
 }
 
 func (job *Job) Setenv(key, value string) {
-	job.env = append(job.env, key+"="+value)
+	job.env.Set(key, value)
 }
 
 // DecodeEnv decodes `src` as a json dictionary, and adds
@@ -187,90 +144,23 @@ func (job *Job) Setenv(key, value string) {
 // If `src` cannot be decoded as a json dictionary, an error
 // is returned.
 func (job *Job) DecodeEnv(src io.Reader) error {
-	m := make(map[string]interface{})
-	if err := json.NewDecoder(src).Decode(&m); err != nil {
-		return err
-	}
-	for k, v := range m {
-		// FIXME: we fix-convert float values to int, because
-		// encoding/json decodes integers to float64, but cannot encode them back.
-		// (See http://golang.org/src/pkg/encoding/json/decode.go#L46)
-		if fval, ok := v.(float64); ok {
-			job.SetenvInt(k, int64(fval))
-		} else if sval, ok := v.(string); ok {
-			job.Setenv(k, sval)
-		} else if val, err := json.Marshal(v); err == nil {
-			job.Setenv(k, string(val))
-		} else {
-			job.Setenv(k, fmt.Sprintf("%v", v))
-		}
-	}
-	return nil
+	return job.env.Decode(src)
 }
 
 func (job *Job) EncodeEnv(dst io.Writer) error {
-	m := make(map[string]interface{})
-	for k, v := range job.Environ() {
-		var val interface{}
-		if err := json.Unmarshal([]byte(v), &val); err == nil {
-			// FIXME: we fix-convert float values to int, because
-			// encoding/json decodes integers to float64, but cannot encode them back.
-			// (See http://golang.org/src/pkg/encoding/json/decode.go#L46)
-			if fval, isFloat := val.(float64); isFloat {
-				val = int(fval)
-			}
-			m[k] = val
-		} else {
-			m[k] = v
-		}
-	}
-	if err := json.NewEncoder(dst).Encode(&m); err != nil {
-		return err
-	}
-	return nil
+	return job.env.Encode(dst)
 }
 
 func (job *Job) ExportEnv(dst interface{}) (err error) {
-	defer func() {
-		if err != nil {
-			err = fmt.Errorf("ExportEnv %s", err)
-		}
-	}()
-	var buf bytes.Buffer
-	// step 1: encode/marshal the env to an intermediary json representation
-	if err := job.EncodeEnv(&buf); err != nil {
-		return err
-	}
-	// step 2: decode/unmarshal the intermediary json into the destination object
-	if err := json.NewDecoder(&buf).Decode(dst); err != nil {
-		return err
-	}
-	return nil
+	return job.env.Export(dst)
 }
 
 func (job *Job) ImportEnv(src interface{}) (err error) {
-	defer func() {
-		if err != nil {
-			err = fmt.Errorf("ImportEnv: %s", err)
-		}
-	}()
-	var buf bytes.Buffer
-	if err := json.NewEncoder(&buf).Encode(src); err != nil {
-		return err
-	}
-	if err := job.DecodeEnv(&buf); err != nil {
-		return err
-	}
-	return nil
+	return job.env.Import(src)
 }
 
 func (job *Job) Environ() map[string]string {
-	m := make(map[string]string)
-	for _, kv := range job.env {
-		parts := strings.SplitN(kv, "=", 2)
-		m[parts[0]] = parts[1]
-	}
-	return m
+	return job.env.Map()
 }
 
 func (job *Job) Logf(format string, args ...interface{}) (n int, err error) {