From 0e80a0f640fa8cbbdede9485e7622eff2ede1714 Mon Sep 17 00:00:00 2001
From: corver <29249923+corverroos@users.noreply.github.com>
Date: Tue, 10 Dec 2024 12:11:51 +0200
Subject: [PATCH] chore(solver/app): instrument inbox processed offset (#2665)

Add metric tracking latest req offset processed by status.

issue: none
---
 solver/app/app.go                     |  3 ++-
 solver/app/helpers.go                 |  9 ++++-----
 solver/app/metrics.go                 | 15 +++++++++++++++
 solver/app/procdeps.go                |  2 ++
 solver/app/processor.go               |  5 +++--
 solver/app/processor_internal_test.go |  1 +
 6 files changed, 27 insertions(+), 8 deletions(-)
 create mode 100644 solver/app/metrics.go

diff --git a/solver/app/app.go b/solver/app/app.go
index 2c33f9bd6..fbc40060d 100644
--- a/solver/app/app.go
+++ b/solver/app/app.go
@@ -205,7 +205,7 @@ func startEventStreams(
 	outboxContracts := make(map[uint64]*bindings.SolveOutbox)
 	for _, chain := range outboxChains {
 		name := network.ChainName(chain)
-		log.Debug(ctx, "Using outbox contract", "chain", name, "address", addrs.SolveInbox.Hex())
+		log.Debug(ctx, "Using outbox contract", "chain", name, "address", addrs.SolveOutbox.Hex())
 
 		backend, err := backends.Backend(chain)
 		if err != nil {
@@ -232,6 +232,7 @@ func startEventStreams(
 		Fulfill:      newFulfiller(network.ID, outboxContracts, backends, solverAddr, addrs.SolveOutbox),
 		Claim:        newClaimer(inboxContracts, backends, solverAddr),
 		SetCursor:    cursorSetter,
+		ChainName:    network.ChainName,
 	}
 
 	for _, chain := range inboxChains {
diff --git a/solver/app/helpers.go b/solver/app/helpers.go
index 29f25e248..96a6106bb 100644
--- a/solver/app/helpers.go
+++ b/solver/app/helpers.go
@@ -2,7 +2,7 @@ package app
 
 import (
 	"context"
-	"encoding/hex"
+	"encoding/binary"
 
 	"github.com/omni-network/omni/lib/errors"
 	"github.com/omni-network/omni/lib/ethclient/ethbackend"
@@ -33,8 +33,7 @@ func detectContractChains(ctx context.Context, network netconf.Network, backends
 	return resp, nil
 }
 
-// fmtReqID returns the least-significant 7 hex chars of the provided request ID.
-// ReqIDs are monotonically incrementing numbers, not hashes.
-func fmtReqID(reqID [32]byte) string {
-	return hex.EncodeToString(reqID[:])[64-7:]
+// reqIDOffset returns the req ID as a uint64 offset (monotonically incrementing number).
+func reqIDOffset(reqID [32]byte) uint64 {
+	return binary.BigEndian.Uint64(reqID[32-8:])
 }
diff --git a/solver/app/metrics.go b/solver/app/metrics.go
new file mode 100644
index 000000000..24e06c1f0
--- /dev/null
+++ b/solver/app/metrics.go
@@ -0,0 +1,15 @@
+package app
+
+import (
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+)
+
+var (
+	statusOffset = promauto.NewGaugeVec(prometheus.GaugeOpts{
+		Namespace: "solver",
+		Subsystem: "processor",
+		Name:      "status_offset",
+		Help:      "Last inbox offset processed by chain and status",
+	}, []string{"chain", "status"})
+)
diff --git a/solver/app/procdeps.go b/solver/app/procdeps.go
index c63a17c05..05e3cd28a 100644
--- a/solver/app/procdeps.go
+++ b/solver/app/procdeps.go
@@ -29,6 +29,8 @@ type procDeps struct {
 	Reject  func(ctx context.Context, chainID uint64, req bindings.SolveRequest, reason rejectReason) error
 	Fulfill func(ctx context.Context, chainID uint64, req bindings.SolveRequest) error
 	Claim   func(ctx context.Context, chainID uint64, req bindings.SolveRequest) error
+
+	ChainName func(chainID uint64) string
 }
 
 func newClaimer(
diff --git a/solver/app/processor.go b/solver/app/processor.go
index 72a37ab0f..24599de20 100644
--- a/solver/app/processor.go
+++ b/solver/app/processor.go
@@ -25,8 +25,9 @@ func newEventProcessor(deps procDeps, chainID uint64) xchain.EventLogsCallback {
 				return errors.Wrap(err, "parse id")
 			}
 
-			ctx := log.WithCtx(ctx, "status", statusString(event.Status), "req_id", fmtReqID(reqID))
-
+			offset := reqIDOffset(reqID)
+			statusOffset.WithLabelValues(deps.ChainName(chainID), statusString(event.Status)).Set(float64(offset))
+			ctx := log.WithCtx(ctx, "status", statusString(event.Status), "req_id", offset)
 			log.Debug(ctx, "Processing event")
 
 			req, _, err := deps.GetRequest(ctx, chainID, reqID)
diff --git a/solver/app/processor_internal_test.go b/solver/app/processor_internal_test.go
index d167e00e8..8aacce89c 100644
--- a/solver/app/processor_internal_test.go
+++ b/solver/app/processor_internal_test.go
@@ -145,6 +145,7 @@ func TestEventProcessor(t *testing.T) {
 
 					return nil
 				},
+				ChainName: func(uint64) string { return "" },
 			}
 
 			processor := newEventProcessor(deps, chainID)