resources: Polish the password PoC and build out send/recv

This polishes the password resource so that it can actually avoid
writing the password to disk, and so that the work actually happens in
CheckApply where it can properly interact with the graph. This resource
now re-generates the password when it receives a notification.

The send/recv plumbing has been extended so that receivers can detect
when they're receiving new values. This is particularly important if
they might otherwise not expect those values to change and cache them
for efficiency purposes.

examples/lib/libmgmt3.go

@@ -58,11 +58,25 @@ func (obj *MyGAPI) Graph() (*pgraph.Graph, error) {
 
 	g := pgraph.NewGraph(obj.Name)
 
+	content := "Delete me to trigger a notification!\n"
+	f0 := &resources.FileRes{
+		BaseRes: resources.BaseRes{
+			Name: "README",
+		},
+		Path:    "/tmp/mgmt/README",
+		Content: &content,
+		State:   "present",
+	}
+
+	v0 := pgraph.NewVertex(f0)
+	g.AddVertex(v0)
+
 	p1 := &resources.PasswordRes{
 		BaseRes: resources.BaseRes{
 			Name: "password1",
 		},
-		Length: 8, // generated string will have this many characters
+		Length: 8,    // generated string will have this many characters
+		Saved:  true, // this causes passwords to be stored in plain text!
 	}
 	v1 := pgraph.NewVertex(p1)
 	g.AddVertex(v1)
@@ -71,11 +85,11 @@ func (obj *MyGAPI) Graph() (*pgraph.Graph, error) {
 		BaseRes: resources.BaseRes{
 			Name: "file1",
 			// send->recv!
-			Recv: map[string]resources.Send{
-				"Content": resources.Send{Res: p1, Key: "Password"},
+			Recv: map[string]*resources.Send{
+				"Content": &resources.Send{Res: p1, Key: "Password"},
 			},
 		},
-		Path: "/tmp/mgmt/f1",
+		Path: "/tmp/mgmt/secret",
 		//Content:  p1.Password, // won't work
 		State: "present",
 	}
@@ -83,17 +97,21 @@ func (obj *MyGAPI) Graph() (*pgraph.Graph, error) {
 	v2 := pgraph.NewVertex(f1)
 	g.AddVertex(v2)
 
-	s1 := &resources.SvcRes{
+	n1 := &resources.NoopRes{
 		BaseRes: resources.BaseRes{
-			Name: "purpleidea",
+			Name: "noop1",
 		},
-		State: "stopped",
 	}
 
-	v3 := pgraph.NewVertex(s1)
+	v3 := pgraph.NewVertex(n1)
 	g.AddVertex(v3)
 
+	e0 := pgraph.NewEdge("e0")
+	e0.Notify = true // send a notification from v0 to v1
+	g.AddEdge(v0, v1, e0)
+
 	g.AddEdge(v1, v2, pgraph.NewEdge("e1"))
+
 	e2 := pgraph.NewEdge("e2")
 	e2.Notify = true // send a notification from v2 to v3
 	g.AddEdge(v2, v3, e2)
@@ -150,7 +168,9 @@ func Run() error {
 	obj := &mgmt.Main{}
 	obj.Program = "libmgmt" // TODO: set on compilation
 	obj.Version = "0.0.1"   // TODO: set on compilation
-	obj.TmpPrefix = true
+	obj.TmpPrefix = true    // disable for easy debugging
+	//prefix := "/tmp/testprefix/"
+	//obj.Prefix = &p // enable for easy debugging
 	obj.IdealClusterSize = -1
 	obj.ConvergedTimeout = -1
 	obj.Noop = false // FIXME: careful!