terraform: make things more linear

terraform/context.go

@@ -81,6 +81,24 @@ func (c *Context2) GraphBuilder() GraphBuilder {
 	}
 }
 
+// Apply applies the changes represented by this context and returns
+// the resulting state.
+//
+// In addition to returning the resulting state, this context is updated
+// with the latest state.
+func (c *Context2) Apply() (*State, error) {
+	// Copy our own state
+	c.state = c.state.deepcopy()
+
+	// Do the walk
+	_, err := c.walk(walkApply)
+
+	// Clean out any unused things
+	c.state.prune()
+
+	return c.state, err
+}
+
 // Plan generates an execution plan for the given context.
 //
 // The execution plan encapsulates the context and can be stored

terraform/context_test.go

@@ -2671,13 +2671,15 @@ func TestContextInput_varOnly(t *testing.T) {
 		t.Fatalf("bad: \n%s", actualStr)
 	}
 }
+*/
 
-func TestContextApply(t *testing.T) {
+/*
+func TestContext2Apply(t *testing.T) {
 	m := testModule(t, "apply-good")
 	p := testProvider("aws")
 	p.ApplyFn = testApplyFn
 	p.DiffFn = testDiffFn
-	ctx := testContext(t, &ContextOpts{
+	ctx := testContext2(t, &ContextOpts{
 		Module: m,
 		Providers: map[string]ResourceProviderFactory{
 			"aws": testProviderFuncFixed(p),
@@ -2705,6 +2707,7 @@ func TestContextApply(t *testing.T) {
 	}
 }
 
+/*
 func TestContextApply_emptyModule(t *testing.T) {
 	m := testModule(t, "apply-empty-module")
 	p := testProvider("aws")

terraform/eval_diff.go

@@ -3,11 +3,12 @@ package terraform
 // EvalDiff is an EvalNode implementation that does a refresh for
 // a resource.
 type EvalDiff struct {
-	Info     *InstanceInfo
-	Config   EvalNode
-	Provider EvalNode
-	State    EvalNode
-	Output   *InstanceDiff
+	Info        *InstanceInfo
+	Config      EvalNode
+	Provider    EvalNode
+	State       EvalNode
+	Output      **InstanceDiff
+	OutputState **InstanceState
 }
 
 func (n *EvalDiff) Args() ([]EvalNode, []EvalType) {
@@ -82,11 +83,12 @@ func (n *EvalDiff) Eval(
 	}
 
 	// Update our output
-	*n.Output = *diff
+	*n.Output = diff
+	*n.OutputState = state
 
 	// Merge our state so that the state is updated with our plan
-	if !diff.Empty() {
-		state = state.MergeDiff(diff)
+	if !diff.Empty() && n.OutputState != nil {
+		*n.OutputState = state.MergeDiff(diff)
 	}
 
 	return state, nil
@@ -101,7 +103,7 @@ func (n *EvalDiff) Type() EvalType {
 type EvalDiffDestroy struct {
 	Info   *InstanceInfo
 	State  EvalNode
-	Output *InstanceDiff
+	Output **InstanceDiff
 }
 
 func (n *EvalDiffDestroy) Args() ([]EvalNode, []EvalType) {
@@ -142,7 +144,7 @@ func (n *EvalDiffDestroy) Eval(
 	}
 
 	// Update our output
-	*n.Output = *diff
+	*n.Output = diff
 
 	return nil, nil
 }
@@ -188,7 +190,7 @@ func (n *EvalDiffDestroyModule) Type() EvalType {
 // the full diff.
 type EvalDiffTainted struct {
 	Name string
-	Diff *InstanceDiff
+	Diff **InstanceDiff
 }
 
 func (n *EvalDiffTainted) Args() ([]EvalNode, []EvalType) {
@@ -218,7 +220,7 @@ func (n *EvalDiffTainted) Eval(
 
 	// If we have tainted, then mark it on the diff
 	if len(rs.Tainted) > 0 {
-		n.Diff.DestroyTainted = true
+		(*n.Diff).DestroyTainted = true
 	}
 
 	return nil, nil
@@ -228,11 +230,46 @@ func (n *EvalDiffTainted) Type() EvalType {
 	return EvalTypeNull
 }
 
+// EvalReadDiff is an EvalNode implementation that writes the diff to
+// the full diff.
+type EvalReadDiff struct {
+	Name string
+	Diff **InstanceDiff
+}
+
+func (n *EvalReadDiff) Args() ([]EvalNode, []EvalType) {
+	return nil, nil
+}
+
+// TODO: test
+func (n *EvalReadDiff) Eval(
+	ctx EvalContext, args []interface{}) (interface{}, error) {
+	diff, lock := ctx.Diff()
+
+	// Acquire the lock so that we can do this safely concurrently
+	lock.Lock()
+	defer lock.Unlock()
+
+	// Write the diff
+	modDiff := diff.ModuleByPath(ctx.Path())
+	if modDiff == nil {
+		return nil, nil
+	}
+
+	*n.Diff = modDiff.Resources[n.Name]
+
+	return nil, nil
+}
+
+func (n *EvalReadDiff) Type() EvalType {
+	return EvalTypeNull
+}
+
 // EvalWriteDiff is an EvalNode implementation that writes the diff to
 // the full diff.
 type EvalWriteDiff struct {
 	Name string
-	Diff *InstanceDiff
+	Diff **InstanceDiff
 }
 
 func (n *EvalWriteDiff) Args() ([]EvalNode, []EvalType) {
@@ -245,7 +282,7 @@ func (n *EvalWriteDiff) Eval(
 	diff, lock := ctx.Diff()
 
 	// The diff to write, if its empty it should write nil
-	diffVal := n.Diff
+	diffVal := *n.Diff
 	if diffVal.Empty() {
 		diffVal = nil
 	}

terraform/eval_provider.go

@@ -55,7 +55,8 @@ func (n *EvalInitProvider) Type() EvalType {
 // EvalGetProvider is an EvalNode implementation that retrieves an already
 // initialized provider instance for the given name.
 type EvalGetProvider struct {
-	Name string
+	Name   string
+	Output *ResourceProvider
 }
 
 func (n *EvalGetProvider) Args() ([]EvalNode, []EvalType) {
@@ -69,6 +70,10 @@ func (n *EvalGetProvider) Eval(
 		return nil, fmt.Errorf("provider %s not initialized", n.Name)
 	}
 
+	if n.Output != nil {
+		*n.Output = result
+	}
+
 	return result, nil
 }
 

terraform/eval_refresh.go

@@ -1,29 +1,31 @@
 package terraform
 
+import (
+	"log"
+)
+
 // EvalRefresh is an EvalNode implementation that does a refresh for
 // a resource.
 type EvalRefresh struct {
 	Provider EvalNode
-	State    EvalNode
+	State    **InstanceState
 	Info     *InstanceInfo
+	Output   **InstanceState
 }
 
 func (n *EvalRefresh) Args() ([]EvalNode, []EvalType) {
-	return []EvalNode{n.Provider, n.State},
-		[]EvalType{EvalTypeResourceProvider, EvalTypeInstanceState}
+	return []EvalNode{n.Provider}, []EvalType{EvalTypeResourceProvider}
 }
 
 // TODO: test
 func (n *EvalRefresh) Eval(
 	ctx EvalContext, args []interface{}) (interface{}, error) {
-	var state *InstanceState
 	provider := args[0].(ResourceProvider)
-	if args[1] != nil {
-		state = args[1].(*InstanceState)
-	}
+	state := *n.State
 
 	// If we have no state, we don't do any refreshing
 	if state == nil {
+		log.Printf("[DEBUG] refresh: %s: no state, not refreshing", n.Info.Id)
 		return nil, nil
 	}
 
@@ -49,6 +51,9 @@ func (n *EvalRefresh) Eval(
 		return nil, err
 	}
 
+	if n.Output != nil {
+		*n.Output = state
+	}
 	return state, nil
 }
 

terraform/eval_state.go

@@ -10,6 +10,7 @@ type EvalReadState struct {
 	Name         string
 	Tainted      bool
 	TaintedIndex int
+	Output       **InstanceState
 }
 
 func (n *EvalReadState) Args() ([]EvalNode, []EvalType) {
@@ -37,13 +38,21 @@ func (n *EvalReadState) Eval(
 		return nil, nil
 	}
 
+	var result *InstanceState
 	if !n.Tainted {
 		// Return the primary
-		return rs.Primary, nil
+		result = rs.Primary
 	} else {
 		// Return the proper tainted resource
-		return rs.Tainted[n.TaintedIndex], nil
+		result = rs.Tainted[n.TaintedIndex]
 	}
+
+	// Write the result to the output pointer
+	if n.Output != nil {
+		*n.Output = result
+	}
+
+	return result, nil
 }
 
 func (n *EvalReadState) Type() EvalType {
@@ -56,23 +65,18 @@ type EvalWriteState struct {
 	Name         string
 	ResourceType string
 	Dependencies []string
-	State        EvalNode
+	State        **InstanceState
 	Tainted      bool
 	TaintedIndex int
 }
 
 func (n *EvalWriteState) Args() ([]EvalNode, []EvalType) {
-	return []EvalNode{n.State}, []EvalType{EvalTypeInstanceState}
+	return nil, nil
 }
 
 // TODO: test
 func (n *EvalWriteState) Eval(
 	ctx EvalContext, args []interface{}) (interface{}, error) {
-	var instanceState *InstanceState
-	if args[0] != nil {
-		instanceState = args[0].(*InstanceState)
-	}
-
 	state, lock := ctx.State()
 	if state == nil {
 		return nil, fmt.Errorf("cannot write state to nil state")
@@ -100,11 +104,11 @@ func (n *EvalWriteState) Eval(
 
 	if n.Tainted {
 		if n.TaintedIndex != -1 {
-			rs.Tainted[n.TaintedIndex] = instanceState
+			rs.Tainted[n.TaintedIndex] = *n.State
 		}
 	} else {
 		// Set the primary state
-		rs.Primary = instanceState
+		rs.Primary = *n.State
 	}
 
 	// Prune because why not, we can clear out old useless entries now

terraform/state.go

@@ -550,7 +550,7 @@ func (r *ResourceState) prune() {
 	n := len(r.Tainted)
 	for i := 0; i < n; i++ {
 		inst := r.Tainted[i]
-		if inst.ID == "" {
+		if inst == nil || inst.ID == "" {
 			copy(r.Tainted[i:], r.Tainted[i+1:])
 			r.Tainted[n-1] = nil
 			n--

terraform/transform_orphan.go

@@ -171,6 +171,8 @@ func (n *graphNodeOrphanResource) ProvidedBy() []string {
 
 // GraphNodeEvalable impl.
 func (n *graphNodeOrphanResource) EvalTree() EvalNode {
+	var state *InstanceState
+
 	seq := &EvalSequence{Nodes: make([]EvalNode, 0, 5)}
 
 	// Build instance info
@@ -180,22 +182,30 @@ func (n *graphNodeOrphanResource) EvalTree() EvalNode {
 	// Refresh the resource
 	seq.Nodes = append(seq.Nodes, &EvalOpFilter{
 		Ops: []walkOperation{walkRefresh},
-		Node: &EvalWriteState{
-			Name:         n.ResourceName,
-			ResourceType: n.ResourceType,
-			Dependencies: n.DependentOn(),
-			State: &EvalRefresh{
-				Info:     info,
-				Provider: &EvalGetProvider{Name: n.ProvidedBy()[0]},
-				State: &EvalReadState{
-					Name: n.ResourceName,
+		Node: &EvalSequence{
+			Nodes: []EvalNode{
+				&EvalReadState{
+					Name:   n.ResourceName,
+					Output: &state,
+				},
+				&EvalRefresh{
+					Info:     info,
+					Provider: &EvalGetProvider{Name: n.ProvidedBy()[0]},
+					State:    &state,
+					Output:   &state,
+				},
+				&EvalWriteState{
+					Name:         n.ResourceName,
+					ResourceType: n.ResourceType,
+					Dependencies: n.DependentOn(),
+					State:        &state,
 				},
 			},
 		},
 	})
 
 	// Diff the resource
-	var diff InstanceDiff
+	var diff *InstanceDiff
 	seq.Nodes = append(seq.Nodes, &EvalOpFilter{
 		Ops: []walkOperation{walkPlan, walkPlanDestroy},
 		Node: &EvalSequence{

terraform/transform_resource.go

@@ -98,6 +98,9 @@ func (n *graphNodeExpandedResource) ProvidedBy() []string {
 
 // GraphNodeEvalable impl.
 func (n *graphNodeExpandedResource) EvalTree() EvalNode {
+	var diff *InstanceDiff
+	var state *InstanceState
+
 	// Build the resource. If we aren't part of a multi-resource, then
 	// we still consider ourselves as count index zero.
 	index := n.Index
@@ -145,35 +148,46 @@ func (n *graphNodeExpandedResource) EvalTree() EvalNode {
 	// Refresh the resource
 	seq.Nodes = append(seq.Nodes, &EvalOpFilter{
 		Ops: []walkOperation{walkRefresh},
-		Node: &EvalWriteState{
-			Name:         n.stateId(),
-			ResourceType: n.Resource.Type,
-			Dependencies: n.DependentOn(),
-			State: &EvalRefresh{
-				Info:     info,
-				Provider: &EvalGetProvider{Name: n.ProvidedBy()[0]},
-				State:    &EvalReadState{Name: n.stateId()},
+		Node: &EvalSequence{
+			Nodes: []EvalNode{
+				&EvalReadState{
+					Name:   n.stateId(),
+					Output: &state,
+				},
+				&EvalRefresh{
+					Info:     info,
+					Provider: &EvalGetProvider{Name: n.ProvidedBy()[0]},
+					State:    &state,
+					Output:   &state,
+				},
+				&EvalWriteState{
+					Name:         n.stateId(),
+					ResourceType: n.Resource.Type,
+					Dependencies: n.DependentOn(),
+					State:        &state,
+				},
 			},
 		},
 	})
 
 	// Diff the resource
-	var diff InstanceDiff
 	seq.Nodes = append(seq.Nodes, &EvalOpFilter{
 		Ops: []walkOperation{walkPlan},
 		Node: &EvalSequence{
 			Nodes: []EvalNode{
+				&EvalDiff{
+					Info:        info,
+					Config:      interpolateNode,
+					Provider:    &EvalGetProvider{Name: n.ProvidedBy()[0]},
+					State:       &EvalReadState{Name: n.stateId()},
+					Output:      &diff,
+					OutputState: &state,
+				},
 				&EvalWriteState{
 					Name:         n.stateId(),
 					ResourceType: n.Resource.Type,
 					Dependencies: n.DependentOn(),
-					State: &EvalDiff{
-						Info:     info,
-						Config:   interpolateNode,
-						Provider: &EvalGetProvider{Name: n.ProvidedBy()[0]},
-						State:    &EvalReadState{Name: n.stateId()},
-						Output:   &diff,
-					},
+					State:        &state,
 				},
 				&EvalDiffTainted{
 					Diff: &diff,
@@ -205,6 +219,41 @@ func (n *graphNodeExpandedResource) EvalTree() EvalNode {
 		},
 	})
 
+	// Diff the resource for destruction
+	var provider ResourceProvider
+	seq.Nodes = append(seq.Nodes, &EvalOpFilter{
+		Ops: []walkOperation{walkApply},
+		Node: &EvalSequence{
+			Nodes: []EvalNode{
+				&EvalGetProvider{
+					Name:   n.ProvidedBy()[0],
+					Output: &provider,
+				},
+				&EvalReadDiff{
+					Name: n.stateId(),
+					Diff: &diff,
+				},
+				&EvalReadState{
+					Name:   n.stateId(),
+					Output: &state,
+				},
+				&EvalApply{
+					Info:     info,
+					State:    &state,
+					Diff:     &diff,
+					Provider: &provider,
+					Output:   &state,
+				},
+				&EvalWriteState{
+					Name:         n.stateId(),
+					ResourceType: n.Resource.Type,
+					Dependencies: n.DependentOn(),
+					State:        &state,
+				},
+			},
+		},
+	})
+
 	return seq
 }
 

terraform/transform_tainted.go

@@ -65,6 +65,8 @@ func (n *graphNodeTaintedResource) ProvidedBy() []string {
 
 // GraphNodeEvalable impl.
 func (n *graphNodeTaintedResource) EvalTree() EvalNode {
+	var state *InstanceState
+
 	seq := &EvalSequence{Nodes: make([]EvalNode, 0, 5)}
 
 	// Build instance info
@@ -74,19 +76,27 @@ func (n *graphNodeTaintedResource) EvalTree() EvalNode {
 	// Refresh the resource
 	seq.Nodes = append(seq.Nodes, &EvalOpFilter{
 		Ops: []walkOperation{walkRefresh},
-		Node: &EvalWriteState{
-			Name:         n.ResourceName,
-			ResourceType: n.ResourceType,
-			Dependencies: n.DependentOn(),
-			Tainted:      true,
-			TaintedIndex: n.Index,
-			State: &EvalRefresh{
-				Info:     info,
-				Provider: &EvalGetProvider{Name: n.ProvidedBy()[0]},
-				State: &EvalReadState{
+		Node: &EvalSequence{
+			Nodes: []EvalNode{
+				&EvalReadState{
 					Name:         n.ResourceName,
 					Tainted:      true,
 					TaintedIndex: n.Index,
+					Output:       &state,
+				},
+				&EvalRefresh{
+					Info:     info,
+					Provider: &EvalGetProvider{Name: n.ProvidedBy()[0]},
+					State:    &state,
+					Output:   &state,
+				},
+				&EvalWriteState{
+					Name:         n.ResourceName,
+					ResourceType: n.ResourceType,
+					Dependencies: n.DependentOn(),
+					State:        &state,
+					Tainted:      true,
+					TaintedIndex: n.Index,
 				},
 			},
 		},