From 733752122a679f9dd09597e3b34728a837fa057c Mon Sep 17 00:00:00 2001 From: Mitchell Hashimoto Date: Wed, 2 Jul 2014 16:16:38 -0700 Subject: [PATCH] terraform: stopHook and tests --- terraform/hook_stop.go | 79 ++++++++++++++ terraform/hook_stop_test.go | 9 ++ terraform/terraform.go | 102 ++++++++++++++++++- terraform/terraform_test.go | 87 ++++++++++++++++ terraform/test-fixtures/apply-cancel/main.tf | 7 ++ 5 files changed, 279 insertions(+), 5 deletions(-) create mode 100644 terraform/hook_stop.go create mode 100644 terraform/hook_stop_test.go create mode 100644 terraform/test-fixtures/apply-cancel/main.tf diff --git a/terraform/hook_stop.go b/terraform/hook_stop.go new file mode 100644 index 000000000..9ed8aacad --- /dev/null +++ b/terraform/hook_stop.go @@ -0,0 +1,79 @@ +package terraform + +import ( + "sync" +) + +// stopHook is a private Hook implementation that Terraform uses to +// signal when to stop or cancel actions. +type stopHook struct { + sync.Mutex + + // This should be incremented for every thing that can be stopped. + // When this is zero, a stopper can assume that everything is properly + // stopped. + count int + + // This channel should be closed when it is time to stop + ch chan struct{} + + serial int + stoppedCh chan<- struct{} +} + +func (h *stopHook) PreApply(string, *ResourceState, *ResourceDiff) (HookAction, error) { + return h.hook() +} + +func (h *stopHook) PostApply(string, *ResourceState) (HookAction, error) { + return h.hook() +} + +func (h *stopHook) PreDiff(string, *ResourceState) (HookAction, error) { + return h.hook() +} + +func (h *stopHook) PostDiff(string, *ResourceDiff) (HookAction, error) { + return h.hook() +} + +func (h *stopHook) PreRefresh(string, *ResourceState) (HookAction, error) { + return h.hook() +} + +func (h *stopHook) PostRefresh(string, *ResourceState) (HookAction, error) { + return h.hook() +} + +func (h *stopHook) hook() (HookAction, error) { + select { + case <-h.ch: + h.stoppedCh <- struct{}{} + return HookActionHalt, nil + default: + return HookActionContinue, nil + } +} + +// reset should be called within the lock context +func (h *stopHook) reset() { + h.ch = make(chan struct{}) + h.count = 0 + h.serial += 1 + h.stoppedCh = nil +} + +func (h *stopHook) ref() int { + h.Lock() + defer h.Unlock() + h.count++ + return h.serial +} + +func (h *stopHook) unref(s int) { + h.Lock() + defer h.Unlock() + if h.serial == s { + h.count-- + } +} diff --git a/terraform/hook_stop_test.go b/terraform/hook_stop_test.go new file mode 100644 index 000000000..2c30231f9 --- /dev/null +++ b/terraform/hook_stop_test.go @@ -0,0 +1,9 @@ +package terraform + +import ( + "testing" +) + +func TestStopHook_impl(t *testing.T) { + var _ Hook = new(stopHook) +} diff --git a/terraform/terraform.go b/terraform/terraform.go index 1cb0f3e0f..9d97a0253 100644 --- a/terraform/terraform.go +++ b/terraform/terraform.go @@ -1,9 +1,11 @@ package terraform import ( + "errors" "fmt" "log" "sync" + "sync/atomic" "github.com/hashicorp/terraform/config" "github.com/hashicorp/terraform/depgraph" @@ -15,12 +17,17 @@ import ( type Terraform struct { hooks []Hook providers map[string]ResourceProviderFactory + stopHook *stopHook } // This is a function type used to implement a walker for the resource // tree internally on the Terraform structure. type genericWalkFunc func(*Resource) (map[string]string, error) +// genericWalkStop is a special return value that can be returned from a +// genericWalkFunc that causes the walk to cease immediately. +var genericWalkStop error + // Config is the configuration that must be given to instantiate // a Terraform structure. type Config struct { @@ -28,6 +35,10 @@ type Config struct { Providers map[string]ResourceProviderFactory } +func init() { + genericWalkStop = errors.New("genericWalkStop") +} + // New creates a new Terraform structure, initializes resource providers // for the given configuration, etc. // @@ -35,13 +46,29 @@ type Config struct { // time, as well as richer checks such as verifying that the resource providers // can be properly initialized, can be configured, etc. func New(c *Config) (*Terraform, error) { + sh := new(stopHook) + sh.Lock() + sh.reset() + sh.Unlock() + + // Copy all the hooks and add our stop hook. We don't append directly + // to the Config so that we're not modifying that in-place. + hooks := make([]Hook, len(c.Hooks)+1) + copy(hooks, c.Hooks) + hooks[len(c.Hooks)] = sh + return &Terraform{ - hooks: c.Hooks, + hooks: hooks, + stopHook: sh, providers: c.Providers, }, nil } func (t *Terraform) Apply(p *Plan) (*State, error) { + // Increase the count on the stop hook so we know when to stop + serial := t.stopHook.ref() + defer t.stopHook.unref(serial) + // Make sure we're working with a plan that doesn't have null pointers // everywhere, and is instead just empty otherwise. p.init() @@ -59,7 +86,40 @@ func (t *Terraform) Apply(p *Plan) (*State, error) { return t.apply(g, p) } +// Stop stops all running tasks (applies, plans, refreshes). +// +// This will block until all running tasks are stopped. While Stop is +// blocked, any new calls to Apply, Plan, Refresh, etc. will also block. New +// calls, however, will start once this Stop has returned. +func (t *Terraform) Stop() { + log.Printf("[INFO] Terraform stopping tasks") + + t.stopHook.Lock() + defer t.stopHook.Unlock() + + // Setup the stoppedCh + stoppedCh := make(chan struct{}, t.stopHook.count) + t.stopHook.stoppedCh = stoppedCh + + // Close the channel to signal that we're done + close(t.stopHook.ch) + + // Expect the number of count stops... + log.Printf("[DEBUG] Waiting for %d tasks to stop", t.stopHook.count) + for i := 0; i < t.stopHook.count; i++ { + <-stoppedCh + } + log.Printf("[DEBUG] Stopped!") + + // Success, everything stopped, reset everything + t.stopHook.reset() +} + func (t *Terraform) Plan(opts *PlanOpts) (*Plan, error) { + // Increase the count on the stop hook so we know when to stop + serial := t.stopHook.ref() + defer t.stopHook.unref(serial) + g, err := Graph(&GraphOpts{ Config: opts.Config, Providers: t.providers, @@ -75,6 +135,10 @@ func (t *Terraform) Plan(opts *PlanOpts) (*Plan, error) { // Refresh goes through all the resources in the state and refreshes them // to their latest status. func (t *Terraform) Refresh(c *config.Config, s *State) (*State, error) { + // Increase the count on the stop hook so we know when to stop + serial := t.stopHook.ref() + defer t.stopHook.unref(serial) + g, err := Graph(&GraphOpts{ Config: c, Providers: t.providers, @@ -175,11 +239,19 @@ func (t *Terraform) applyWalkFn( // anything and that the diff has no computed values (pre-computed) for _, h := range t.hooks { - // TODO: return value - h.PreApply(r.Id, r.State, diff) + a, err := h.PreApply(r.Id, r.State, diff) + if err != nil { + return nil, err + } + + switch a { + case HookActionHalt: + return nil, genericWalkStop + } } // With the completed diff, apply! + log.Printf("[DEBUG] %s: Executing Apply", r.Id) rs, err := r.Provider.Apply(r.State, diff) if err != nil { return nil, err @@ -219,8 +291,15 @@ func (t *Terraform) applyWalkFn( r.State = rs for _, h := range t.hooks { - // TODO: return value - h.PostApply(r.Id, r.State) + a, err := h.PostApply(r.Id, r.State) + if err != nil { + return nil, err + } + + switch a { + case HookActionHalt: + return nil, genericWalkStop + } } // Determine the new state and update variables @@ -305,12 +384,20 @@ func (t *Terraform) genericWalkFn( vars[fmt.Sprintf("var.%s", k)] = v } + // This will keep track of whether we're stopped or not + var stop uint32 = 0 + return func(n *depgraph.Noun) error { // If it is the root node, ignore if n.Name == GraphRootNode { return nil } + // If we're stopped, return right away + if atomic.LoadUint32(&stop) != 0 { + return nil + } + switch m := n.Meta.(type) { case *GraphNodeResource: case *GraphNodeResourceProvider: @@ -363,6 +450,11 @@ func (t *Terraform) genericWalkFn( log.Printf("[INFO] Walking: %s", rn.Resource.Id) newVars, err := cb(rn.Resource) if err != nil { + if err == genericWalkStop { + atomic.StoreUint32(&stop, 1) + return nil + } + return err } diff --git a/terraform/terraform_test.go b/terraform/terraform_test.go index 6350eb50c..c1075cf73 100644 --- a/terraform/terraform_test.go +++ b/terraform/terraform_test.go @@ -39,6 +39,87 @@ func TestTerraformApply(t *testing.T) { } } +func TestTerraformApply_cancel(t *testing.T) { + stopped := false + stopCh := make(chan struct{}) + stopReplyCh := make(chan struct{}) + + rpAWS := new(MockResourceProvider) + rpAWS.ResourcesReturn = []ResourceType{ + ResourceType{Name: "aws_instance"}, + } + rpAWS.DiffFn = func(*ResourceState, *ResourceConfig) (*ResourceDiff, error) { + return &ResourceDiff{ + Attributes: map[string]*ResourceAttrDiff{ + "num": &ResourceAttrDiff{ + New: "bar", + }, + }, + }, nil + } + rpAWS.ApplyFn = func(*ResourceState, *ResourceDiff) (*ResourceState, error) { + if !stopped { + stopped = true + close(stopCh) + <-stopReplyCh + } + + return &ResourceState{ + ID: "foo", + Attributes: map[string]string{ + "num": "2", + }, + }, nil + } + + c := testConfig(t, "apply-cancel") + tf := testTerraform2(t, &Config{ + Providers: map[string]ResourceProviderFactory{ + "aws": testProviderFuncFixed(rpAWS), + }, + }) + + p, err := tf.Plan(&PlanOpts{Config: c}) + if err != nil { + t.Fatalf("err: %s", err) + } + + // Start the Apply in a goroutine + stateCh := make(chan *State) + go func() { + state, err := tf.Apply(p) + if err != nil { + panic(err) + } + + stateCh <- state + }() + + // Start a goroutine so we can inject exactly when we stop + s := tf.stopHook.ref() + go func() { + defer tf.stopHook.unref(s) + <-tf.stopHook.ch + close(stopReplyCh) + tf.stopHook.stoppedCh <- struct{}{} + }() + + <-stopCh + tf.Stop() + + state := <-stateCh + + if len(state.Resources) != 1 { + t.Fatalf("bad: %#v", state.Resources) + } + + actual := strings.TrimSpace(state.String()) + expected := strings.TrimSpace(testTerraformApplyCancelStr) + if actual != expected { + t.Fatalf("bad: \n%s", actual) + } +} + func TestTerraformApply_compute(t *testing.T) { // This tests that computed variables are properly re-diffed // to get the value prior to application (Apply). @@ -683,6 +764,12 @@ aws_instance.foo: type = aws_instance ` +const testTerraformApplyCancelStr = ` +aws_instance.foo: + ID = foo + num = 2 +` + const testTerraformApplyComputeStr = ` aws_instance.bar: ID = foo diff --git a/terraform/test-fixtures/apply-cancel/main.tf b/terraform/test-fixtures/apply-cancel/main.tf new file mode 100644 index 000000000..94ed55478 --- /dev/null +++ b/terraform/test-fixtures/apply-cancel/main.tf @@ -0,0 +1,7 @@ +resource "aws_instance" "foo" { + num = "2" +} + +resource "aws_instance" "bar" { + foo = "${aws_instance.foo.num}" +}