feat(api): expose deviation values in stable text encoding

Signed-off-by: Markus Vahlenkamp <markus.vahlenkamp@nokia.com>

Author: steiler

pkg/api/deviation.go

@@ -24,10 +24,15 @@ const (
 )
 
 // DeviationEntry is one deviating path with its expected and current values.
+// Expected and Current are display strings; ExpectedText and CurrentText carry
+// the same values in the stable text encoding that stored deviations use. An
+// absent value is empty in both forms.
 type DeviationEntry struct {
-	Path     string
-	Expected string
-	Current  string
+	Path         string
+	Expected     string
+	Current      string
+	ExpectedText string
+	CurrentText  string
 }
 
 // DeviationEvent is emitted by a deviation watch. Intent, Reason and Entries

pkg/core/deviation.go

@@ -145,6 +145,9 @@ func toDeviationEvent(rsp *sdcpb.WatchDeviationResponse) api.DeviationEvent {
 			Path:     rsp.GetPath().ToXPath(false),
 			Expected: valueString(rsp.GetExpectedValue()),
 			Current:  valueString(rsp.GetCurrentValue()),
+
+			ExpectedText: valueText(rsp.GetExpectedValue()),
+			CurrentText:  valueText(rsp.GetCurrentValue()),
 		}}
 	}
 	return ev

pkg/core/rpc_test.go

@@ -13,6 +13,7 @@ import (
 	"github.com/sdcio/data-server/pkg/datastore"
 	targettypes "github.com/sdcio/data-server/pkg/datastore/target/types"
 	sdcpb "github.com/sdcio/sdc-protos/sdcpb"
+	"google.golang.org/protobuf/encoding/prototext"
 )
 
 const ifPath = "/interface[name=ethernet-1/1]"
@@ -375,3 +376,21 @@ func TestDeviationWatcherSendUnblocksOnCancel(t *testing.T) {
 		t.Fatal("send after close must fail")
 	}
 }
+
+func TestToDeviationEventEntryText(t *testing.T) {
+	rsp := &sdcpb.WatchDeviationResponse{
+		Event:         sdcpb.DeviationEvent_UPDATE,
+		ExpectedValue: &sdcpb.TypedValue{Value: &sdcpb.TypedValue_StringVal{StringVal: "a"}},
+	}
+	e := toDeviationEvent(rsp).Entries[0]
+	var tv sdcpb.TypedValue
+	if err := prototext.Unmarshal([]byte(e.ExpectedText), &tv); err != nil {
+		t.Fatalf("ExpectedText is not prototext: %v", err)
+	}
+	if tv.GetStringVal() != "a" {
+		t.Fatalf("round trip mismatch: %v", &tv)
+	}
+	if e.CurrentText != "" {
+		t.Fatalf("absent value must be empty, got %q", e.CurrentText)
+	}
+}

pkg/core/transaction.go

@@ -4,6 +4,8 @@ import (
 	"context"
 	"fmt"
 
+	"google.golang.org/protobuf/encoding/prototext"
+
 	"github.com/sdcio/data-server/pkg/api"
 	"github.com/sdcio/data-server/pkg/datastore"
 	"github.com/sdcio/data-server/pkg/datastore/types"
@@ -175,3 +177,15 @@ func valueString(tv *sdcpb.TypedValue) string {
 	}
 	return tv.ToString()
 }
+
+// valueText encodes a typed value as prototext; nil encodes as empty.
+func valueText(tv *sdcpb.TypedValue) string {
+	if tv == nil {
+		return ""
+	}
+	b, err := prototext.Marshal(tv)
+	if err != nil {
+		return ""
+	}
+	return string(b)
+}