engine: Resources package rewrite

This giant patch makes some much needed improvements to the code base.

* The engine has been rewritten and lives within engine/graph/
* All of the common interfaces and code now live in engine/
* All of the resources are in one package called engine/resources/
* The Res API can use different "traits" from engine/traits/
* The Res API has been simplified to hide many of the old internals
* The Watch & Process loops were previously inverted, but is now fixed
* The likelihood of package cycles has been reduced drastically
* And much, much more...

Unfortunately, some code had to be temporarily removed. The remote code
had to be taken out, as did the prometheus code. We hope to have these
back in new forms as soon as possible.

examples/lib/libmgmt-subgraph1.go

@@ -10,10 +10,11 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/purpleidea/mgmt/engine"
+	"github.com/purpleidea/mgmt/engine/resources"
 	"github.com/purpleidea/mgmt/gapi"
 	mgmt "github.com/purpleidea/mgmt/lib"
 	"github.com/purpleidea/mgmt/pgraph"
-	"github.com/purpleidea/mgmt/resources"
 
 	"github.com/urfave/cli"
 )
@@ -49,7 +50,7 @@ func NewMyGAPI(data gapi.Data, name string, interval uint) (*MyGAPI, error) {
 // should take the prefix of the registered name. On activation, if there are
 // any validation problems, you should return an error. If this was not
 // activated, then you should return a nil GAPI and a nil error.
-func (obj *MyGAPI) Cli(c *cli.Context, fs resources.Fs) (*gapi.Deploy, error) {
+func (obj *MyGAPI) Cli(c *cli.Context, fs engine.Fs) (*gapi.Deploy, error) {
 	if s := c.String(obj.Name); c.IsSet(obj.Name) {
 		if s != "" {
 			return nil, fmt.Errorf("input is not empty")
@@ -103,15 +104,8 @@ func (obj *MyGAPI) Graph() (*pgraph.Graph, error) {
 		return nil, err
 	}
 
-	metaparams := resources.DefaultMetaParams
-
 	content := "I created a subgraph!\n"
 	f0 := &resources.FileRes{
-		BaseRes: resources.BaseRes{
-			Name:       "README",
-			Kind:       "file",
-			MetaParams: metaparams,
-		},
 		Path:    "/tmp/mgmt/README",
 		Content: &content,
 		State:   "present",
@@ -126,40 +120,24 @@ func (obj *MyGAPI) Graph() (*pgraph.Graph, error) {
 
 	// add elements into the sub graph
 	f1 := &resources.FileRes{
-		BaseRes: resources.BaseRes{
-			Name:       "file1",
-			Kind:       "file",
-			MetaParams: metaparams,
-		},
 		Path: "/tmp/mgmt/sub1",
 
 		State: "present",
 	}
 	subGraph.AddVertex(f1)
 
-	n1 := &resources.NoopRes{
-		BaseRes: resources.BaseRes{
-			Name:       "noop1",
-			Kind:       "noop",
-			MetaParams: metaparams,
-		},
-	}
+	n1 := &resources.NoopRes{}
 	subGraph.AddVertex(n1)
 
-	e0 := &resources.Edge{Name: "e0"}
+	e0 := &engine.Edge{Name: "e0"}
 	e0.Notify = true // send a notification from v0 to v1
 	subGraph.AddEdge(f1, n1, e0)
 
 	// create the actual resource to hold the sub graph
-	subGraphRes0 := &resources.GraphRes{ // TODO: should we name this SubGraphRes ?
-		BaseRes: resources.BaseRes{
-			Name:       "subgraph1",
-			Kind:       "graph",
-			MetaParams: metaparams,
-		},
-		Graph: subGraph,
-	}
-	g.AddVertex(subGraphRes0) // add it to the main graph
+	//subGraphRes0 := &resources.GraphRes{ // TODO: should we name this SubGraphRes ?
+	//	Graph: subGraph,
+	//}
+	//g.AddVertex(subGraphRes0) // add it to the main graph
 
 	//g, err := config.NewGraphFromConfig(obj.data.Hostname, obj.data.World, obj.data.Noop)
 	return g, nil