From f06d5b02a273cf3b3bd0fa279471b49e02d132f4 Mon Sep 17 00:00:00 2001
From: Gert Drapers <gert.drapers@live.com>
Date: Thu, 16 Nov 2023 21:05:30 -0800
Subject: [PATCH] manifest & model etag

---
 pkg/bdb/migrate/mig003/migrate.go | 7 +++++++
 pkg/ds/manifest.go                | 6 ++++++
 2 files changed, 13 insertions(+)

diff --git a/pkg/bdb/migrate/mig003/migrate.go b/pkg/bdb/migrate/mig003/migrate.go
index 20a15a6..ffa7257 100644
--- a/pkg/bdb/migrate/mig003/migrate.go
+++ b/pkg/bdb/migrate/mig003/migrate.go
@@ -3,8 +3,10 @@ package mig003
 import (
 	"bytes"
 	"context"
+	"hash/fnv"
 	"os"
 	"path/filepath"
+	"strconv"
 
 	"github.com/aserto-dev/azm/migrate"
 	v3 "github.com/aserto-dev/azm/v3"
@@ -91,8 +93,13 @@ func createModel() func(*zerolog.Logger, *bolt.DB, *bolt.DB) error {
 			return err
 		}
 
+		h := fnv.New64a()
+		h.Reset()
+		_, _ = h.Write(manifestBuf.Bytes())
+
 		md := &dsm3.Metadata{
 			UpdatedAt: timestamppb.Now(),
+			Etag:      strconv.FormatUint(h.Sum64(), 10),
 		}
 		if err := rwDB.Update(func(tx *bolt.Tx) error {
 			if err := ds.Manifest(md).Set(ctx, tx, manifestBuf); err != nil {
diff --git a/pkg/ds/manifest.go b/pkg/ds/manifest.go
index d219084..9389f36 100644
--- a/pkg/ds/manifest.go
+++ b/pkg/ds/manifest.go
@@ -84,6 +84,12 @@ func (m *manifest) Set(ctx context.Context, tx *bolt.Tx, buf *bytes.Buffer) erro
 // SetModel, persists the model cache in the _manifest bucket
 // _metadata/{name}/{version}/model.
 func (m *manifest) SetModel(ctx context.Context, tx *bolt.Tx, mod *model.Model) error {
+	if mod.Metadata == nil {
+		mod.Metadata = &model.Metadata{}
+	}
+	mod.Metadata.ETag = m.Metadata.Etag
+	mod.Metadata.UpdatedAt = m.Metadata.UpdatedAt.AsTime()
+
 	if _, err := bdb.SetAny[model.Model](ctx, tx, bdb.ManifestPath, bdb.ModelKey, mod); err != nil {
 		return err
 	}