helm/pkg/tiller/hooks.go

/*
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 (
	"fmt"
	"log"
	"path"
	"strconv"
	"strings"

	"github.com/ghodss/yaml"

	"k8s.io/helm/pkg/chartutil"
	"k8s.io/helm/pkg/hooks"
	"k8s.io/helm/pkg/proto/hapi/release"
	util "k8s.io/helm/pkg/releaseutil"
)

var events = map[string]release.Hook_Event{
	hooks.PreInstall:         release.Hook_PRE_INSTALL,
	hooks.PostInstall:        release.Hook_POST_INSTALL,
	hooks.PreDelete:          release.Hook_PRE_DELETE,
	hooks.PostDelete:         release.Hook_POST_DELETE,
	hooks.PreUpgrade:         release.Hook_PRE_UPGRADE,
	hooks.PostUpgrade:        release.Hook_POST_UPGRADE,
	hooks.PreRollback:        release.Hook_PRE_ROLLBACK,
	hooks.PostRollback:       release.Hook_POST_ROLLBACK,
	hooks.ReleaseTestSuccess: release.Hook_RELEASE_TEST_SUCCESS,
	hooks.ReleaseTestFailure: release.Hook_RELEASE_TEST_FAILURE,
}

// manifest represents a manifest file, which has a name and some content.
type manifest struct {
	name    string
	content string
	head    *util.SimpleHead
}

type result struct {
	hooks   []*release.Hook
	generic []manifest
}

type manifestFile struct {
	entries map[string]string
	path    string
	apis    chartutil.VersionSet
}

// sortManifests takes a map of filename/YAML contents, splits the file
// by manifest entries, and sorts the entries into hook types.
//
// The resulting hooks struct will be populated with all of the generated hooks.
// Any file that does not declare one of the hook types will be placed in the
// 'generic' bucket.
//
// Files that do not parse into the expected format are simply placed into a map and
// returned.
func sortManifests(files map[string]string, apis chartutil.VersionSet, sort SortOrder) ([]*release.Hook, []manifest, error) {
	result := &result{}

	for filePath, c := range files {

		// Skip partials. We could return these as a separate map, but there doesn't
		// seem to be any need for that at this time.
		if strings.HasPrefix(path.Base(filePath), "_") {
			continue
		}
		// Skip empty files and log this.
		if len(strings.TrimSpace(c)) == 0 {
			log.Printf("info: manifest %q is empty. Skipping.", filePath)
			continue
		}

		manifestFile := &manifestFile{
			entries: util.SplitManifests(c),
			path:    filePath,
			apis:    apis,
		}

		if err := manifestFile.sort(result); err != nil {
			return result.hooks, result.generic, err
		}
	}

	return result.hooks, sortByKind(result.generic, sort), nil
}

// sort takes a manifestFile object which may contain multiple resource definition
// entries and sorts each entry by hook types, and saves the resulting hooks and
// generic manifests (or non-hooks) to the result struct.
//
// To determine hook type, it looks for a YAML structure like this:
//
//  kind: SomeKind
//  apiVersion: v1
// 	metadata:
//		annotations:
//			helm.sh/hook: pre-install
//
func (file *manifestFile) sort(result *result) error {
	for _, m := range file.entries {
		var entry util.SimpleHead
		err := yaml.Unmarshal([]byte(m), &entry)

		if err != nil {
			e := fmt.Errorf("YAML parse error on %s: %s", file.path, err)
			return e
		}

		if entry.Version != "" && !file.apis.Has(entry.Version) {
			return fmt.Errorf("apiVersion %q in %s is not available", entry.Version, file.path)
		}

		if !hasAnyAnnotation(entry) {
			result.generic = append(result.generic, manifest{
				name:    file.path,
				content: m,
				head:    &entry,
			})
			continue
		}

		hookTypes, ok := entry.Metadata.Annotations[hooks.HookAnno]
		if !ok {
			result.generic = append(result.generic, manifest{
				name:    file.path,
				content: m,
				head:    &entry,
			})
			continue
		}

		hw := calculateHookWeight(entry)

		h := &release.Hook{
			Name:     entry.Metadata.Name,
			Kind:     entry.Kind,
			Path:     file.path,
			Manifest: m,
			Events:   []release.Hook_Event{},
			Weight:   hw,
		}

		isKnownHook := false
		for _, hookType := range strings.Split(hookTypes, ",") {
			hookType = strings.ToLower(strings.TrimSpace(hookType))
			e, ok := events[hookType]
			if ok {
				isKnownHook = true
				h.Events = append(h.Events, e)
			}
		}

		if !isKnownHook {
			log.Printf("info: skipping unknown hook: %q", hookTypes)
			continue
		}

		result.hooks = append(result.hooks, h)
	}

	return nil
}

func hasAnyAnnotation(entry util.SimpleHead) bool {
	if entry.Metadata == nil ||
		entry.Metadata.Annotations == nil ||
		len(entry.Metadata.Annotations) == 0 {
		return false
	}

	return true
}

func calculateHookWeight(entry util.SimpleHead) int32 {
	hws, _ := entry.Metadata.Annotations[hooks.HookWeightAnno]
	hw, err := strconv.Atoi(hws)
	if err != nil {
		hw = 0
	}

	return int32(hw)
}