feat: add created_at/updated_at columns to cluster and machines store tables

internal/machine/store/schema.sql

@@ -2,7 +2,9 @@
 CREATE TABLE cluster
 (
     key        TEXT      NOT NULL PRIMARY KEY,
-    value ANY
+    value      ANY,
+    -- updated_at is the last time the value was written.
+    updated_at TIMESTAMP NOT NULL DEFAULT '1970-01-01 00:00:00'
 );
 
 -- machines table stores the basic information of the machines in the cluster.
@@ -11,8 +13,11 @@ CREATE TABLE machines
     id         TEXT      NOT NULL PRIMARY KEY,
     name       TEXT AS (json_extract(info, '$.name')),
     -- info is a JSON-serialized MachineInfo protobuf message.
-    info TEXT NOT NULL DEFAULT '{}' CHECK (json_valid(info))
-    -- TODO: add created_at and updated_at fields to track machine age and last update time.
+    info       TEXT      NOT NULL DEFAULT '{}' CHECK (json_valid(info)),
+    -- created_at is the time the machine record was created.
+    created_at TIMESTAMP NOT NULL DEFAULT '1970-01-01 00:00:00',
+    -- updated_at is the last time the machine record was updated.
+    updated_at TIMESTAMP NOT NULL DEFAULT '1970-01-01 00:00:00'
 );
 
 -- containers table stores the Uncloud-managed Docker containers created in the cluster.

internal/machine/store/store.go

@@ -49,7 +49,9 @@ func (s *Store) Get(ctx context.Context, key string, value any) error {
 }
 
 func (s *Store) Put(ctx context.Context, key string, value any) error {
-	_, err := s.corro.ExecContext(ctx, "INSERT OR REPLACE INTO cluster (key, value) VALUES (?, ?)", key, value)
+	_, err := s.corro.ExecContext(ctx,
+		"INSERT OR REPLACE INTO cluster (key, value, updated_at) VALUES (?, ?, datetime('now'))",
+		key, value)
 	return err
 }
 
@@ -119,7 +121,9 @@ func (s *Store) CreateMachine(ctx context.Context, m *pb.MachineInfo) error {
 	if err != nil {
 		return fmt.Errorf("marshal machine info: %w", err)
 	}
-	_, err = s.corro.ExecContext(ctx, "INSERT INTO machines (id, info) VALUES (?, ?)", m.Id, string(mJSON))
+	_, err = s.corro.ExecContext(ctx,
+		"INSERT INTO machines (id, info, created_at, updated_at) VALUES (?, ?, datetime('now'), datetime('now'))",
+		m.Id, string(mJSON))
 	if err != nil {
 		return fmt.Errorf("insert query: %w", err)
 	}
@@ -231,7 +235,9 @@ func (s *Store) UpdateMachine(ctx context.Context, m *pb.MachineInfo) error {
 		return fmt.Errorf("marshal machine info: %w", err)
 	}
 
-	result, err := s.corro.ExecContext(ctx, "UPDATE machines SET info = ? WHERE id = ?", string(mJSON), m.Id)
+	result, err := s.corro.ExecContext(ctx,
+		"UPDATE machines SET info = ?, updated_at = datetime('now') WHERE id = ?",
+		string(mJSON), m.Id)
 	if err != nil {
 		return fmt.Errorf("update machine: %w", err)
 	}