chore: handle push of unchanged schema

cache/cache.go

@@ -2,6 +2,7 @@ package cache
 
 import (
 	"fmt"
+	"time"
 
 	"github.com/apex/log"
 	"github.com/sparetimecoders/goamqp"
@@ -12,17 +13,20 @@ import (
 const subGraphKey = "%s<->%s"
 
 type Cache struct {
-	services  map[string]map[string]struct{}
-	subGraphs map[string]string
-	logger    log.Interface
+	services   map[string]map[string]struct{}
+	subGraphs  map[string]string
+	lastUpdate map[string]string
+	logger     log.Interface
 }
 
-func (c *Cache) Services(ref string) []string {
+func (c *Cache) Services(ref, lastUpdate string) ([]string, string) {
 	var services []string
-	for k := range c.services[ref] {
-		services = append(services, k)
+	if lastUpdate == "" || c.lastUpdate[ref] > lastUpdate {
+		for k := range c.services[ref] {
+			services = append(services, k)
+		}
 	}
-	return services
+	return services, c.lastUpdate[ref]
 }
 
 func (c *Cache) SubGraphId(ref, service string) string {
@@ -37,12 +41,14 @@ func (c *Cache) Update(msg any, _ goamqp.Headers) (any, error) {
 		}
 		c.services[m.Ref][m.ID.String()] = struct{}{}
 		c.subGraphs[fmt.Sprintf(subGraphKey, m.Ref, m.Service)] = m.ID.String()
+		c.lastUpdate[m.Ref] = m.Time.Format(time.RFC3339Nano)
 	case *domain.SubGraph:
 		if _, exists := c.services[m.Ref]; !exists {
 			c.services[m.Ref] = make(map[string]struct{})
 		}
 		c.services[m.Ref][m.ID.String()] = struct{}{}
 		c.subGraphs[fmt.Sprintf(subGraphKey, m.Ref, m.Service)] = m.ID.String()
+		c.lastUpdate[m.Ref] = m.ChangedAt.Format(time.RFC3339Nano)
 	default:
 		c.logger.Warnf("unexpected message received: %+v", msg)
 	}
@@ -51,8 +57,9 @@ func (c *Cache) Update(msg any, _ goamqp.Headers) (any, error) {
 
 func New(logger log.Interface) *Cache {
 	return &Cache{
-		subGraphs: make(map[string]string),
-		services:  make(map[string]map[string]struct{}),
-		logger:    logger,
+		subGraphs:  make(map[string]string),
+		services:   make(map[string]map[string]struct{}),
+		lastUpdate: make(map[string]string),
+		logger:     logger,
 	}
 }