Send relation changes from the model cache worker to the model cache.

hopkings2008 · Jan 17, 2020 · f31e3ad · f31e3ad
1 parent 2f7af88
commit f31e3ad
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diff --git a/core/cache/changes.go b/core/cache/changes.go
@@ -178,6 +178,44 @@ type RemoveUnit struct {
 	Name      string
 }
 
+// RelationChange represents either a new relation, or a change
+// to an existing relation in a model.
+type RelationChange struct {
+	ModelUUID string
+	Key       string
+	Endpoints []Endpoint
+}
+
+// Endpoint holds all relevant information about a relation endpoint.
+type Endpoint struct {
+	Application string
+	Name        string
+	Role        string
+	Interface   string
+	Optional    bool
+	Limit       int
+	Scope       string
+}
+
+// copy returns a deep copy of the RelationChange.
+func (c RelationChange) copy() RelationChange {
+	if existing := c.Endpoints; existing != nil {
+		endpoints := make([]Endpoint, len(existing))
+		for i, ep := range existing {
+			endpoints[i] = ep
+		}
+		c.Endpoints = existing
+	}
+	return c
+}
+
+// RemoveRelation represents the situation when a relation
+// is removed from a model in the database.
+type RemoveRelation struct {
+	ModelUUID string
+	Key       string
+}
+
 // MachineChange represents either a new machine, or a change
 // to an existing machine in a model.
 type MachineChange struct {

diff --git a/worker/modelcache/worker.go b/worker/modelcache/worker.go
@@ -313,6 +313,8 @@ func (c *cacheWorker) translate(d multiwatcher.Delta) interface{} {
 		return c.translateMachine(d)
 	case multiwatcher.UnitKind:
 		return c.translateUnit(d)
+	case multiwatcher.RelationKind:
+		return c.translateRelation(d)
 	case multiwatcher.CharmKind:
 		return c.translateCharm(d)
 	case multiwatcher.BranchKind:
@@ -459,6 +461,43 @@ func (c *cacheWorker) translateUnit(d multiwatcher.Delta) interface{} {
 	}
 }
 
+func (c *cacheWorker) translateRelation(d multiwatcher.Delta) interface{} {
+	e := d.Entity
+	id := e.EntityID()
+
+	if d.Removed {
+		return cache.RemoveRelation{
+			ModelUUID: id.ModelUUID,
+			Name:      id.ID,
+		}
+	}
+
+	value, ok := e.(*multiwatcher.RelationInfo)
+	if !ok {
+		c.config.Logger.Errorf("unexpected type %T", e)
+		return nil
+	}
+
+	endpoints := make([]cache.Endpoint, len(value.Endpoints))
+	for i, ep := range value.Endpoints{
+		endpoints[i] := cache.Endpoint{
+			Application: value.ApplicationName,
+			Name: value.Relation.Name,
+			Role: value.Relation.Role,
+			Interface: value.Relation.Interface,
+			Optional: value.Relation.Optional,
+			Limit: value.Relation.Limit,
+			Scope: value.Relation.Scope,
+		}
+	}
+
+	return cache.RelationChange{
+		ModelUUID:      value.ModelUUID,
+		Key:           value.Key,
+		Endpoints:    endpoints,
+	}
+}
+
 func (c *cacheWorker) translateCharm(d multiwatcher.Delta) interface{} {
 	e := d.Entity
 	id := e.EntityID()