feat(hooks): Adds weighted hooks

closes #2136
* Adds new annotation `helm.sh/hookWeight`
* Sorts executing hooks of similar kind in ascending order
* There is no upper or lower bounds on the weights

pkg/hooks/hooks.go

@@ -23,6 +23,9 @@ import (
 // HookAnno is the label name for a hook
 const HookAnno = "helm.sh/hook"
 
+// HookWeightAnno is the label name for a hook weight
+const HookWeightAnno = "helm.sh/hookWeight"
+
 // Types of hooks
 const (
 	PreInstall         = "pre-install"

pkg/proto/hapi/release/hook.pb.go

@@ -100,6 +100,8 @@ type Hook struct {
 	Events []Hook_Event `protobuf:"varint,5,rep,packed,name=events,enum=hapi.release.Hook_Event" json:"events,omitempty"`
 	// LastRun indicates the date/time this was last run.
 	LastRun *google_protobuf.Timestamp `protobuf:"bytes,6,opt,name=last_run,json=lastRun" json:"last_run,omitempty"`
+	// Weight indicates the sort order for execution among similar Hook types
+	Weight int `protobuf:"bytes,7,opt,name=weight" json:"weight,omitempty"`
 }
 
 func (m *Hook) Reset()                    { *m = Hook{} }

pkg/tiller/hook_sorter.go

@@ -0,0 +1,53 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package tiller
+
+import (
+	"sort"
+
+	"k8s.io/helm/pkg/proto/hapi/release"
+)
+
+// sortByHookWeight does an in-place sort of hooks by their supplied weight.
+func sortByHookWeight(hooks []*release.Hook) []*release.Hook {
+	hs := newHookWeightSorter(hooks)
+	sort.Sort(hs)
+	return hs.hooks
+}
+
+type hookWeightSorter struct {
+	hooks []*release.Hook
+}
+
+func newHookWeightSorter(h []*release.Hook) *hookWeightSorter {
+	return &hookWeightSorter{
+		hooks: h,
+	}
+}
+
+func (hs *hookWeightSorter) Len() int { return len(hs.hooks) }
+
+func (hs *hookWeightSorter) Swap(i, j int) {
+	hs.hooks[i], hs.hooks[j] = hs.hooks[j], hs.hooks[i]
+}
+
+func (hs *hookWeightSorter) Less(i, j int) bool {
+	if hs.hooks[i].Weight == hs.hooks[j].Weight {
+		return hs.hooks[i].Name < hs.hooks[j].Name
+	}
+	return hs.hooks[i].Weight < hs.hooks[j].Weight
+}

pkg/tiller/hook_sorter_test.go

@@ -0,0 +1,73 @@
+/*
+Copyright 2017 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package tiller
+
+import (
+	"testing"
+
+	"k8s.io/helm/pkg/proto/hapi/release"
+)
+
+func TestHookSorter(t *testing.T) {
+	hooks := []*release.Hook{
+		{
+			Name:   "g",
+			Kind:   "pre-install",
+			Weight: 99,
+		},
+		{
+			Name:   "f",
+			Kind:   "pre-install",
+			Weight: 3,
+		},
+		{
+			Name:   "b",
+			Kind:   "pre-install",
+			Weight: -3,
+		},
+		{
+			Name:   "e",
+			Kind:   "pre-install",
+			Weight: 3,
+		},
+		{
+			Name:   "a",
+			Kind:   "pre-install",
+			Weight: -10,
+		},
+		{
+			Name:   "c",
+			Kind:   "pre-install",
+			Weight: 0,
+		},
+		{
+			Name:   "d",
+			Kind:   "pre-install",
+			Weight: 3,
+		},
+	}
+
+	res := sortByHookWeight(hooks)
+	got := ""
+	expect := "abcdefg"
+	for _, r := range res {
+		got += r.Name
+	}
+	if got != expect {
+		t.Errorf("Expected %q, got %q", expect, got)
+	}
+}

pkg/tiller/hooks.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"log"
 	"path"
+	"strconv"
 	"strings"
 
 	"github.com/ghodss/yaml"
@@ -109,12 +110,21 @@ func sortManifests(files map[string]string, apis chartutil.VersionSet, sort Sort
 			generic = append(generic, manifest{name: n, content: c, head: &sh})
 			continue
 		}
+
+		hw := 0
+		hws, _ := sh.Metadata.Annotations[hooks.HookWeightAnno]
+		hw, err = strconv.Atoi(hws)
+		if err != nil {
+			hw = 0
+		}
+
 		h := &release.Hook{
 			Name:     sh.Metadata.Name,
 			Kind:     sh.Kind,
 			Path:     n,
 			Manifest: c,
 			Events:   []release.Hook_Event{},
+			Weight:   hw,
 		}
 
 		isHook := false

pkg/tiller/release_server.go

@@ -911,17 +911,18 @@ func (s *ReleaseServer) execHook(hs []*release.Hook, name, namespace, hook strin
 	}
 
 	log.Printf("Executing %s hooks for %s", hook, name)
+	executingHooks := []*release.Hook{}
 	for _, h := range hs {
-		found := false
 		for _, e := range h.Events {
 			if e == code {
-				found = true
+				executingHooks = append(executingHooks, h)
 			}
 		}
-		// If this doesn't implement the hook, skip it.
-		if !found {
-			continue
-		}
+	}
+
+	executingHooks = sortByHookWeight(executingHooks)
+
+	for _, h := range executingHooks {
 
 		b := bytes.NewBufferString(h.Manifest)
 		if err := kubeCli.Create(namespace, b, timeout, false); err != nil {
@@ -937,6 +938,7 @@ func (s *ReleaseServer) execHook(hs []*release.Hook, name, namespace, hook strin
 		}
 		h.LastRun = timeconv.Now()
 	}
+
 	log.Printf("Hooks complete for %s %s", hook, name)
 	return nil
 }