resources: Replace stored pgraph with mgraph and clean up hacks

Now that we're using our meta wrapper graph struct instead of the
pgraph, we can re-implement our SetValue hacks in terms of struct fields
and the implementation is now cleaner.

resources/actions.go

@@ -69,7 +69,7 @@ func (obj *BaseRes) Poke() error {
 	// if we're pausing (or exiting) then we should suspend poke's so that
 	// the graph doesn't go on running forever until it's completely done!
 	// this is an optional feature which we can do by default on user exit
-	if b, ok := obj.Graph.Value("fastpause"); ok && util.Bool(b) {
+	if obj.Graph.FastPause {
 		return nil // TODO: should this be an error instead?
 	}
 
@@ -199,15 +199,15 @@ func (obj *BaseRes) Process() error {
 	// The exception is that semaphores with a zero count will always block!
 	// TODO: Add a close mechanism to close/unblock zero count semaphores...
 	semas := obj.Meta().Sema
-	if b, ok := obj.Graph.Value("debug"); ok && util.Bool(b) && len(semas) > 0 {
+	if obj.debug && len(semas) > 0 {
 		log.Printf("%s: Sema: P(%s)", obj, strings.Join(semas, ", "))
 	}
-	if err := SemaLock(obj.Graph, semas); err != nil { // lock
+	if err := obj.Graph.SemaLock(semas); err != nil { // lock
 		// NOTE: in practice, this might not ever be truly necessary...
 		return fmt.Errorf("shutdown of semaphores")
 	}
-	defer SemaUnlock(obj.Graph, semas) // unlock
-	if b, ok := obj.Graph.Value("debug"); ok && util.Bool(b) && len(semas) > 0 {
+	defer obj.Graph.SemaUnlock(semas) // unlock
+	if obj.debug && len(semas) > 0 {
 		defer log.Printf("%s: Sema: V(%s)", obj, strings.Join(semas, ", "))
 	}
 

resources/mgraph.go

@@ -23,6 +23,7 @@ import (
 
 	"github.com/purpleidea/mgmt/event"
 	"github.com/purpleidea/mgmt/pgraph"
+	"github.com/purpleidea/mgmt/util/semaphore"
 )
 
 //go:generate stringer -type=graphState -output=graphstate_stringer.go
@@ -42,19 +43,24 @@ type MGraph struct {
 	//Graph *pgraph.Graph
 	*pgraph.Graph // wrap a graph, and use its methods directly
 
-	Data  *ResData
-	Debug bool
+	Data      *ResData
+	FastPause bool
+	Debug     bool
 
 	state graphState
 	// ptr b/c: Mutex/WaitGroup must not be copied after first use
 	mutex *sync.Mutex
 	wg    *sync.WaitGroup
+	slock *sync.Mutex
+	semas map[string]*semaphore.Semaphore
 }
 
 // Init initializes the internal structures.
 func (obj *MGraph) Init() {
 	obj.mutex = &sync.Mutex{}
 	obj.wg = &sync.WaitGroup{}
+	obj.slock = &sync.Mutex{} // semaphore lock
+	obj.semas = make(map[string]*semaphore.Semaphore)
 }
 
 // getState returns the state of the graph. This state is used for optimizing
@@ -84,7 +90,6 @@ func (obj *MGraph) Update(newGraph *pgraph.Graph) {
 	for _, v := range obj.Graph.Vertices() {
 		res := VtoR(v)          // resource
 		*res.Data() = *obj.Data // push the data around
-		res.Update(obj.Graph)   // update graph pointer
 	}
 }
 
@@ -107,7 +112,7 @@ func (obj *MGraph) Start(first bool) { // start or continue
 				// NOTE: vertex == res here, but pass in both in
 				// case we ever wrap the res in something before
 				// we store it as the vertex in the graph struct
-				res.Setup(obj.Graph, vertex, res) // initialize some vars in the resource
+				res.Setup(obj, vertex, res) // initialize some vars in the resource
 			}
 		}(v, VtoR(v))
 	}
@@ -183,13 +188,13 @@ func (obj *MGraph) Pause(fastPause bool) {
 	log.Printf("State: %v -> %v", obj.setState(graphStatePausing), obj.getState())
 	defer log.Printf("State: %v -> %v", obj.setState(graphStatePaused), obj.getState())
 	if fastPause {
-		obj.Graph.SetValue("fastpause", true) // set flag
+		obj.FastPause = true // set flag
 	}
 	t, _ := obj.Graph.TopologicalSort()
 	for _, v := range t { // squeeze out the events...
 		VtoR(v).SendEvent(event.EventPause, nil) // sync
 	}
-	obj.Graph.SetValue("fastpause", false) // reset flag
+	obj.FastPause = false // reset flag
 }
 
 // Exit sends exit events to the graph in a topological sort order.

resources/resources.go

@@ -117,8 +117,7 @@ type Base interface {
 	Events() chan *event.Event
 	Data() *ResData
 	Working() *bool
-	Setup(*pgraph.Graph, pgraph.Vertex, Res)
-	Update(*pgraph.Graph)
+	Setup(*MGraph, pgraph.Vertex, Res)
 	Reset()
 	Exit()
 	GetState() ResState
@@ -167,7 +166,7 @@ type Res interface {
 // BaseRes is the base struct that gets used in every resource.
 type BaseRes struct {
 	Res    Res           // pointer to full res
-	Graph  *pgraph.Graph // pointer to graph I'm currently in
+	Graph  *MGraph       // pointer to graph I'm currently in
 	Vertex pgraph.Vertex // pointer to vertex I currently am
 
 	Recv       map[string]*Send // mapping of key to receive on from value
@@ -344,7 +343,7 @@ func (obj *BaseRes) Working() *bool {
 // Setup does some work which must happen before the Worker starts. It happens
 // once per Worker startup. It can happen in parallel with other Setup calls, so
 // add locks around any operation that's not thread-safe.
-func (obj *BaseRes) Setup(graph *pgraph.Graph, vertex pgraph.Vertex, res Res) {
+func (obj *BaseRes) Setup(mgraph *MGraph, vertex pgraph.Vertex, res Res) {
 	obj.started = make(chan struct{}) // closes when started
 	obj.stopped = make(chan struct{}) // closes when stopped
 
@@ -354,12 +353,7 @@ func (obj *BaseRes) Setup(graph *pgraph.Graph, vertex pgraph.Vertex, res Res) {
 
 	obj.Res = res       // store a pointer to the full object
 	obj.Vertex = vertex // store a pointer to the vertex i'm
-	obj.Graph = graph   // store a pointer to the graph we're in
-}
-
-// Update refreshes the internal graph pointer that we're primarily used in.
-func (obj *BaseRes) Update(graph *pgraph.Graph) {
-	obj.Graph = graph // store a pointer to the graph i'm in
+	obj.Graph = mgraph  // store a pointer to the graph we're in
 }
 
 // Reset from Setup. These can get called for different vertices in parallel.

resources/semaphore.go

@@ -22,9 +22,7 @@ import (
 	"sort"
 	"strconv"
 	"strings"
-	"sync"
 
-	"github.com/purpleidea/mgmt/pgraph"
 	"github.com/purpleidea/mgmt/util/semaphore"
 
 	multierr "github.com/hashicorp/go-multierror"
@@ -34,21 +32,19 @@ import (
 const SemaSep = ":"
 
 // SemaLock acquires the list of semaphores in the graph.
-func SemaLock(g *pgraph.Graph, semas []string) error {
+func (obj *MGraph) SemaLock(semas []string) error {
 	var reterr error
 	sort.Strings(semas) // very important to avoid deadlock in the dag!
-	slock := SemaLockFromGraph(g)
-	smap := SemaMapFromGraph(g) // returns a map, which can be modified by ref
 
 	for _, id := range semas {
-		slock.Lock()         // semaphore creation lock
-		sema, ok := smap[id] // lookup
+		obj.slock.Lock()          // semaphore creation lock
+		sema, ok := obj.semas[id] // lookup
 		if !ok {
 			size := SemaSize(id) // defaults to 1
-			smap[id] = semaphore.NewSemaphore(size)
-			sema = smap[id]
+			obj.semas[id] = semaphore.NewSemaphore(size)
+			sema = obj.semas[id]
 		}
-		slock.Unlock()
+		obj.slock.Unlock()
 
 		if err := sema.P(1); err != nil { // lock!
 			reterr = multierr.Append(reterr, err) // list of errors
@@ -58,13 +54,12 @@ func SemaLock(g *pgraph.Graph, semas []string) error {
 }
 
 // SemaUnlock releases the list of semaphores in the graph.
-func SemaUnlock(g *pgraph.Graph, semas []string) error {
+func (obj *MGraph) SemaUnlock(semas []string) error {
 	var reterr error
 	sort.Strings(semas) // unlock in the same order to remove partial locks
-	smap := SemaMapFromGraph(g)
 
 	for _, id := range semas {
-		sema, ok := smap[id] // lookup
+		sema, ok := obj.semas[id] // lookup
 		if !ok {
 			// programming error!
 			panic(fmt.Sprintf("graph: sema: %s does not exist", id))
@@ -90,36 +85,3 @@ func SemaSize(id string) int {
 	}
 	return size
 }
-
-// SemaLockFromGraph returns a pointer to the semaphore lock stored with the
-// graph, otherwise it panics. If one does not exist, it will create it.
-func SemaLockFromGraph(g *pgraph.Graph) *sync.Mutex {
-	x, exists := g.Value("slock")
-	if !exists {
-		g.SetValue("slock", &sync.Mutex{})
-		x, _ = g.Value("slock")
-	}
-
-	slock, ok := x.(*sync.Mutex)
-	if !ok {
-		panic("not a *sync.Mutex")
-	}
-	return slock
-}
-
-// SemaMapFromGraph returns a pointer to the map of semaphores stored with the
-// graph, otherwise it panics. If one does not exist, it will create it.
-func SemaMapFromGraph(g *pgraph.Graph) map[string]*semaphore.Semaphore {
-	x, exists := g.Value("semas")
-	if !exists {
-		semas := make(map[string]*semaphore.Semaphore)
-		g.SetValue("semas", semas)
-		x, _ = g.Value("semas")
-	}
-
-	semas, ok := x.(map[string]*semaphore.Semaphore)
-	if !ok {
-		panic("not a map[string]*semaphore.Semaphore")
-	}
-	return semas
-}