metering for consensus cap (#1099)

* metering for consensus cap

* Adding MeterableCapability iface

* clean up

* removing MeterableCapability iface in favor of MeteringUnit struct

* fixing tests

* values.ByteSizeOfMap --> private utility

* updating access pattern to metering.unit

* metering.XyzMeteringUnit --> metering.XyzUnit

Author: patrickhuie19

pkg/capabilities/consensus/ocr3/capability.go

@@ -7,11 +7,13 @@ import (
 	"time"
 
 	"github.com/jonboulle/clockwork"
+	"google.golang.org/protobuf/proto"
 
 	"github.com/smartcontractkit/chainlink-common/pkg/capabilities"
 	"github.com/smartcontractkit/chainlink-common/pkg/capabilities/consensus/ocr3/requests"
 	"github.com/smartcontractkit/chainlink-common/pkg/capabilities/consensus/ocr3/types"
 	"github.com/smartcontractkit/chainlink-common/pkg/logger"
+	"github.com/smartcontractkit/chainlink-common/pkg/metering"
 	"github.com/smartcontractkit/chainlink-common/pkg/services"
 	"github.com/smartcontractkit/chainlink-common/pkg/values"
 )
@@ -212,6 +214,7 @@ func (o *capability) Execute(ctx context.Context, r capabilities.CapabilityReque
 		if err != nil {
 			return capabilities.CapabilityResponse{}, err
 		}
+		inputLenBytes := byteSizeOfMap(r.Inputs)
 
 		config, err := o.ValidateConfig(r.Config)
 		if err != nil {
@@ -224,8 +227,14 @@ func (o *capability) Execute(ctx context.Context, r capabilities.CapabilityReque
 		}
 
 		response := <-ch
+		outputLenBytes := byteSizeOfMap(response.Value)
 		return capabilities.CapabilityResponse{
 			Value: response.Value,
+			Metadata: capabilities.ResponseMetadata{
+				Metering: []capabilities.MeteringNodeDetail{
+					{SpendUnit: metering.PayloadUnit.Name, SpendValue: fmt.Sprintf("%d", inputLenBytes+outputLenBytes)},
+				},
+			},
 		}, response.Err
 	}
 
@@ -276,3 +285,14 @@ func (o *capability) queueRequestForProcessing(
 	o.reqHandler.SendRequest(ctx, r)
 	return callbackCh, nil
 }
+
+// byteSizeOfMap is a utility to get the wire-size
+// of a values.Map.
+func byteSizeOfMap(m *values.Map) int {
+	if m == nil {
+		return 0
+	}
+	pbVal := values.Proto(m)
+	size := proto.Size(pbVal)
+	return size
+}

pkg/capabilities/consensus/ocr3/capability_test.go

@@ -139,6 +139,8 @@ func TestOCR3Capability(t *testing.T) {
 			assert.NoError(t, resp.Err)
 
 			assert.Equal(t, mresp, resp.Value)
+			assert.Equal(t, "payload", resp.Metadata.Metering[0].SpendUnit)
+			assert.Equal(t, "122", resp.Metadata.Metering[0].SpendValue)
 		})
 	}
 }
@@ -459,7 +461,7 @@ func TestOCR3Capability_RespondsToLateRequest(t *testing.T) {
 		Value: obsv,
 	}
 
-	assert.Equal(t, expectedCapabilityResponse, response)
+	assert.Equal(t, expectedCapabilityResponse.Value, response.Value)
 }
 
 func TestOCR3Capability_RespondingToLateRequestDoesNotBlockOnSlowResponseConsumer(t *testing.T) {
@@ -519,7 +521,7 @@ func TestOCR3Capability_RespondingToLateRequestDoesNotBlockOnSlowResponseConsume
 		Value: obsv,
 	}
 
-	assert.Equal(t, expectedCapabilityResponse, resp)
+	assert.Equal(t, expectedCapabilityResponse.Value, resp.Value)
 }
 
 type asyncCapabilityResponse struct {
@@ -531,7 +533,7 @@ func executeAsync(ctx context.Context, request capabilities.CapabilityRequest, t
 	respCh := make(chan asyncCapabilityResponse, 1)
 	go func() {
 		resp, err := toExecute(ctx, request)
-		respCh <- asyncCapabilityResponse{CapabilityResponse: capabilities.CapabilityResponse{Value: resp.Value}, Err: err}
+		respCh <- asyncCapabilityResponse{CapabilityResponse: capabilities.CapabilityResponse{Value: resp.Value, Metadata: resp.Metadata}, Err: err}
 		close(respCh)
 	}()
 

pkg/metering/units.go

@@ -0,0 +1,20 @@
+package metering
+
+var (
+	PayloadUnit = unit{Name: "payload", Unit: "bytes"}
+
+	// ComputeUnit is an example. The compute cap will eventually be obsoleted
+	// by the CRE No-DAG SDK.
+	ComputeUnit = unit{Name: "compute", Unit: "seconds"}
+)
+
+// unit provides exported Name and unit fields for
+// capability devs to consume when implementing
+// metering. Do not export.
+type unit struct {
+	// Name of the Metering Unit, i.e. payload, compute, storage
+	Name string
+
+	// Unit of the Metering Unit, i.e. bytes, seconds
+	Unit string
+}