mcfg: implement SourceEnv, and move a bunch of code it shares with SourceCLI to source(_test).go

mcfg/cli_test.go

@@ -2,14 +2,11 @@ package mcfg
 
 import (
 	"bytes"
-	"encoding/json"
-	"fmt"
 	"strings"
 	. "testing"
 	"time"
 
 	"github.com/mediocregopher/mediocre-go-lib/mrand"
-	"github.com/mediocregopher/mediocre-go-lib/mtest/massert"
 	"github.com/mediocregopher/mediocre-go-lib/mtest/mchk"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -46,105 +43,35 @@ func TestSourceCLIHelp(t *T) {
 
 func TestSourceCLI(t *T) {
 	type state struct {
-		cfg       *Cfg
+		srcCommonState
-		availCfgs []*Cfg
-
 		SourceCLI
-		expPVs []ParamValue
 	}
 
 	type params struct {
-		name        string
+		srcCommonParams
-		availCfgI   int // not technically needed, but makes subsequent steps easier
+		nonBoolWEq bool // use equal sign when setting value
-		path        []string
-		isBool      bool
-		nonBoolType string // "int", "str", "duration", "json"
-		unset       bool
-		nonBoolWEq  bool // use equal sign when setting value
-		nonBoolVal  string
 	}
 
 	chk := mchk.Checker{
 		Init: func() mchk.State {
 			var s state
-			s.cfg = New()
+			s.srcCommonState = newSrcCommonState()
-			{
-				a := s.cfg.Child("a")
-				b := s.cfg.Child("b")
-				c := s.cfg.Child("c")
-				ab := a.Child("b")
-				bc := b.Child("c")
-				abc := ab.Child("c")
-				s.availCfgs = []*Cfg{s.cfg, a, b, c, ab, bc, abc}
-			}
 			s.SourceCLI.Args = make([]string, 0, 16)
 			return s
 		},
 		Next: func(ss mchk.State) mchk.Action {
 			s := ss.(state)
 			var p params
-			if i := mrand.Intn(8); i == 0 {
+			p.srcCommonParams = s.srcCommonState.next()
-				p.name = mrand.Hex(1) + "-" + mrand.Hex(8)
+			// if the param is a bool or unset this won't get used, but w/e
-			} else if i == 1 {
-				p.name = mrand.Hex(1) + "=" + mrand.Hex(8)
-			} else {
-				p.name = mrand.Hex(8)
-			}
-
-			p.availCfgI = mrand.Intn(len(s.availCfgs))
-			thisCfg := s.availCfgs[p.availCfgI]
-			p.path = thisCfg.Path
-
-			p.isBool = mrand.Intn(2) == 0
-			if !p.isBool {
-				p.nonBoolType = mrand.Element([]string{
-					"int",
-					"str",
-					"duration",
-					"json",
-				}, nil).(string)
-			}
-			p.unset = mrand.Intn(10) == 0
-
-			if p.isBool || p.unset {
-				return mchk.Action{Params: p}
-			}
-
 			p.nonBoolWEq = mrand.Intn(2) == 0
-			switch p.nonBoolType {
-			case "int":
-				p.nonBoolVal = fmt.Sprint(mrand.Int())
-			case "str":
-				p.nonBoolVal = mrand.Hex(16)
-			case "duration":
-				dur := time.Duration(mrand.Intn(86400)) * time.Second
-				p.nonBoolVal = dur.String()
-			case "json":
-				b, _ := json.Marshal(map[string]int{
-					mrand.Hex(4): mrand.Int(),
-					mrand.Hex(4): mrand.Int(),
-					mrand.Hex(4): mrand.Int(),
-				})
-				p.nonBoolVal = string(b)
-			}
 			return mchk.Action{Params: p}
 		},
 		Apply: func(ss mchk.State, a mchk.Action) (mchk.State, error) {
 			s := ss.(state)
 			p := a.Params.(params)
 
-			// the param needs to get added to its cfg as a Param
+			s.srcCommonState = s.srcCommonState.applyCfgAndPV(p.srcCommonParams)
-			thisCfg := s.availCfgs[p.availCfgI]
-			cfgP := Param{
-				Name:     p.name,
-				IsString: p.nonBoolType == "str" || p.nonBoolType == "duration",
-				IsBool:   p.isBool,
-				// the cli parser doesn't actually care about the other fields of Param,
-				// those are only used by Cfg once it has all ParamValues together
-			}
-			thisCfg.ParamAdd(cfgP)
-
-			// if the arg is set then add it to the cli args and the expected output pvs
 			if !p.unset {
 				arg := cliKeyPrefix
 				if len(p.path) > 0 {
@@ -161,39 +88,14 @@ func TestSourceCLI(t *T) {
 					arg += p.nonBoolVal
 				}
 				s.SourceCLI.Args = append(s.SourceCLI.Args, arg)
-
-				pv := ParamValue{
-					Param: cfgP,
-					Path:  p.path,
-				}
-				if p.isBool {
-					pv.Value = json.RawMessage("true")
-				} else {
-					switch p.nonBoolType {
-					case "str", "duration":
-						pv.Value = json.RawMessage(fmt.Sprintf("%q", p.nonBoolVal))
-					case "int", "json":
-						pv.Value = json.RawMessage(p.nonBoolVal)
-					default:
-						panic("shouldn't get here")
-					}
-				}
-				s.expPVs = append(s.expPVs, pv)
 			}
 
-			// and finally the state needs to be checked
+			err := s.srcCommonState.assert(s.SourceCLI)
-			gotPVs, err := s.SourceCLI.Parse(s.cfg)
+			return s, err
-			if err != nil {
-				return nil, err
-			}
-			return s, massert.All(
-				massert.Len(gotPVs, len(s.expPVs)),
-				massert.Subset(s.expPVs, gotPVs),
-			).Assert()
 		},
 	}
 
-	if err := chk.RunFor(5 * time.Second); err != nil {
+	if err := chk.RunFor(2 * time.Second); err != nil {
 		t.Fatal(err)
 	}
 }

mcfg/env.go

@@ -0,0 +1,78 @@
+package mcfg
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"strings"
+)
+
+// SourceEnv is a Source which will parse configuration from the process
+// environment.
+//
+// Possible Env options are generated by joining a Param's Path and Name with
+// underscores and making all characters uppercase, as well as changing all
+// dashes to underscores.
+//
+//	cfg := mcfg.New().Child("foo").Child("bar")
+//	addr := cfg.ParamString("srv-addr", "", "Some address")
+//	// the Env option to fill addr will be "FOO_BAR_SRV_ADDR"
+//
+type SourceEnv struct {
+	Env []string // in the format key=value
+
+	// If set then all expected Env options must be prefixed with this string,
+	// which will be uppercased and have dashes replaced with underscores like
+	// all the other parts of the option names.
+	Prefix string
+}
+
+func (env SourceEnv) expectedName(path []string, name string) string {
+	out := strings.Join(append(path, name), "_")
+	if env.Prefix != "" {
+		out = env.Prefix + "_" + out
+	}
+	out = strings.Replace(out, "-", "_", -1)
+	out = strings.ToUpper(out)
+	return out
+}
+
+// Parse implements the method for the Source interface
+func (env SourceEnv) Parse(cfg *Cfg) ([]ParamValue, error) {
+	kvs := env.Env
+	if kvs == nil {
+		kvs = os.Environ()
+	}
+
+	pvM := map[string]ParamValue{}
+	for _, pv := range cfg.allParamValues() {
+		name := env.expectedName(pv.Path, pv.Name)
+		pvM[name] = pv
+	}
+
+	pvs := make([]ParamValue, 0, len(kvs))
+	for _, kv := range kvs {
+		split := strings.SplitN(kv, "=", 2)
+		if len(split) != 2 {
+			return nil, fmt.Errorf("malformed environment kv %q", kv)
+		}
+		k, v := split[0], split[1]
+		if pv, ok := pvM[k]; ok {
+			if pv.IsBool {
+				if v == "" {
+					pv.Value = json.RawMessage("false")
+				} else {
+					pv.Value = json.RawMessage("true")
+				}
+			} else if pv.IsString && (v == "" || v[0] != '"') {
+				pv.Value = json.RawMessage(`"` + v + `"`)
+
+			} else {
+				pv.Value = json.RawMessage(v)
+			}
+			pvs = append(pvs, pv)
+		}
+	}
+
+	return pvs, nil
+}

mcfg/env_test.go

@@ -0,0 +1,58 @@
+package mcfg
+
+import (
+	"strings"
+	. "testing"
+	"time"
+
+	"github.com/mediocregopher/mediocre-go-lib/mtest/mchk"
+)
+
+func TestSourceEnv(t *T) {
+	type state struct {
+		srcCommonState
+		SourceEnv
+	}
+
+	type params struct {
+		srcCommonParams
+	}
+
+	chk := mchk.Checker{
+		Init: func() mchk.State {
+			var s state
+			s.srcCommonState = newSrcCommonState()
+			s.SourceEnv.Env = make([]string, 0, 16)
+			return s
+		},
+		Next: func(ss mchk.State) mchk.Action {
+			s := ss.(state)
+			var p params
+			p.srcCommonParams = s.srcCommonState.next()
+			return mchk.Action{Params: p}
+		},
+		Apply: func(ss mchk.State, a mchk.Action) (mchk.State, error) {
+			s := ss.(state)
+			p := a.Params.(params)
+			s.srcCommonState = s.srcCommonState.applyCfgAndPV(p.srcCommonParams)
+			if !p.unset {
+				kv := strings.Join(append(p.path, p.name), "_")
+				kv = strings.Replace(kv, "-", "_", -1)
+				kv = strings.ToUpper(kv)
+				kv += "="
+				if p.isBool {
+					kv += "1"
+				} else {
+					kv += p.nonBoolVal
+				}
+				s.SourceEnv.Env = append(s.SourceEnv.Env, kv)
+			}
+			err := s.srcCommonState.assert(s.SourceEnv)
+			return s, err
+		},
+	}
+
+	if err := chk.RunFor(2 * time.Second); err != nil {
+		t.Fatal(err)
+	}
+}

mcfg/source_test.go

@@ -0,0 +1,142 @@
+package mcfg
+
+import (
+	"encoding/json"
+	"fmt"
+	"time"
+
+	"github.com/mediocregopher/mediocre-go-lib/mrand"
+	"github.com/mediocregopher/mediocre-go-lib/mtest/massert"
+)
+
+// The tests for the different Sources use mchk as their primary method of
+// checking. They end up sharing a lot of the same functionality, so in here is
+// all the code they share
+
+type srcCommonState struct {
+	cfg       *Cfg
+	availCfgs []*Cfg
+	expPVs    []ParamValue
+
+	// each specific test should wrap this to add the Source itself
+}
+
+func newSrcCommonState() srcCommonState {
+	var scs srcCommonState
+	scs.cfg = New()
+	{
+		a := scs.cfg.Child("a")
+		b := scs.cfg.Child("b")
+		c := scs.cfg.Child("c")
+		ab := a.Child("b")
+		bc := b.Child("c")
+		abc := ab.Child("c")
+		scs.availCfgs = []*Cfg{scs.cfg, a, b, c, ab, bc, abc}
+	}
+	return scs
+}
+
+type srcCommonParams struct {
+	name        string
+	availCfgI   int // not technically needed, but finding the cfg easier
+	path        []string
+	isBool      bool
+	nonBoolType string // "int", "str", "duration", "json"
+	unset       bool
+	nonBoolVal  string
+}
+
+func (scs srcCommonState) next() srcCommonParams {
+	var p srcCommonParams
+	if i := mrand.Intn(8); i == 0 {
+		p.name = mrand.Hex(1) + "-" + mrand.Hex(8)
+	} else {
+		p.name = mrand.Hex(8)
+	}
+
+	p.availCfgI = mrand.Intn(len(scs.availCfgs))
+	thisCfg := scs.availCfgs[p.availCfgI]
+	p.path = thisCfg.Path
+
+	p.isBool = mrand.Intn(2) == 0
+	if !p.isBool {
+		p.nonBoolType = mrand.Element([]string{
+			"int",
+			"str",
+			"duration",
+			"json",
+		}, nil).(string)
+	}
+	p.unset = mrand.Intn(10) == 0
+
+	if p.isBool || p.unset {
+		return p
+	}
+
+	switch p.nonBoolType {
+	case "int":
+		p.nonBoolVal = fmt.Sprint(mrand.Int())
+	case "str":
+		p.nonBoolVal = mrand.Hex(16)
+	case "duration":
+		dur := time.Duration(mrand.Intn(86400)) * time.Second
+		p.nonBoolVal = dur.String()
+	case "json":
+		b, _ := json.Marshal(map[string]int{
+			mrand.Hex(4): mrand.Int(),
+			mrand.Hex(4): mrand.Int(),
+			mrand.Hex(4): mrand.Int(),
+		})
+		p.nonBoolVal = string(b)
+	}
+	return p
+}
+
+// adds the new cfg param to the cfg, and if the param is expected to be set in
+// the Source adds it to the expected ParamValues as well
+func (scs srcCommonState) applyCfgAndPV(p srcCommonParams) srcCommonState {
+	thisCfg := scs.availCfgs[p.availCfgI]
+	cfgP := Param{
+		Name:     p.name,
+		IsString: p.nonBoolType == "str" || p.nonBoolType == "duration",
+		IsBool:   p.isBool,
+		// the Sources don't actually care about the other fields of Param,
+		// those are only used by Cfg once it has all ParamValues together
+	}
+	thisCfg.ParamAdd(cfgP)
+
+	if !p.unset {
+		pv := ParamValue{
+			Param: cfgP,
+			Path:  p.path,
+		}
+		if p.isBool {
+			pv.Value = json.RawMessage("true")
+		} else {
+			switch p.nonBoolType {
+			case "str", "duration":
+				pv.Value = json.RawMessage(fmt.Sprintf("%q", p.nonBoolVal))
+			case "int", "json":
+				pv.Value = json.RawMessage(p.nonBoolVal)
+			default:
+				panic("shouldn't get here")
+			}
+		}
+		scs.expPVs = append(scs.expPVs, pv)
+	}
+
+	return scs
+}
+
+// given a Source asserts that it's Parse method returns the expected
+// ParamValues
+func (scs srcCommonState) assert(s Source) error {
+	gotPVs, err := s.Parse(scs.cfg)
+	if err != nil {
+		return err
+	}
+	return massert.All(
+		massert.Len(gotPVs, len(scs.expPVs)),
+		massert.Subset(scs.expPVs, gotPVs),
+	).Assert()
+}