summaryrefslogtreecommitdiff
path: root/pkg/hooks/hooks.go
blob: 66e97d6bd9df28e3fd644e599d047a272d5196e0 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
// Package hooks implements hook configuration and handling for CRI-O and libpod.
package hooks

import (
	"context"
	"fmt"
	"path/filepath"
	"sync"

	rspec "github.com/opencontainers/runtime-spec/specs-go"
	"github.com/pkg/errors"
	current "github.com/projectatomic/libpod/pkg/hooks/1.0.0"
	"golang.org/x/text/collate"
	"golang.org/x/text/language"
)

// Version is the current hook configuration version.
const Version = current.Version

const (
	// DefaultDir is the default directory containing system hook configuration files.
	DefaultDir = "/usr/share/containers/oci/hooks.d"

	// OverrideDir is the directory for hook configuration files overriding the default entries.
	OverrideDir = "/etc/containers/oci/hooks.d"
)

// Manager provides an opaque interface for managing CRI-O hooks.
type Manager struct {
	hooks           map[string]*current.Hook
	directories     []string
	extensionStages []string
	language        language.Tag
	lock            sync.Mutex
}

type namedHook struct {
	name string
	hook *current.Hook
}

type namedHooks []*namedHook

// New creates a new hook manager.  Directories are ordered by
// increasing preference (hook configurations in later directories
// override configurations with the same filename from earlier
// directories).
func New(ctx context.Context, directories []string, extensionStages []string, lang language.Tag) (manager *Manager, err error) {
	manager = &Manager{
		hooks:           map[string]*current.Hook{},
		directories:     directories,
		extensionStages: extensionStages,
		language:        lang,
	}

	for _, dir := range directories {
		err = ReadDir(dir, manager.extensionStages, manager.hooks)
		if err != nil {
			return nil, err
		}
	}

	return manager, nil
}

// filenames returns sorted hook entries.
func (m *Manager) namedHooks() (hooks []*namedHook) {
	m.lock.Lock()
	defer m.lock.Unlock()

	hooks = make([]*namedHook, len(m.hooks))
	i := 0
	for name, hook := range m.hooks {
		hooks[i] = &namedHook{
			name: name,
			hook: hook,
		}
		i++
	}

	return hooks
}

// Hooks injects OCI runtime hooks for a given container configuration.
func (m *Manager) Hooks(config *rspec.Spec, annotations map[string]string, hasBindMounts bool) (extensionStages map[string][]rspec.Hook, err error) {
	hooks := m.namedHooks()
	collator := collate.New(m.language, collate.IgnoreCase, collate.IgnoreWidth)
	collator.Sort(namedHooks(hooks))
	validStages := map[string]bool{} // beyond the OCI stages
	for _, stage := range m.extensionStages {
		validStages[stage] = true
	}
	for _, namedHook := range hooks {
		match, err := namedHook.hook.When.Match(config, annotations, hasBindMounts)
		if err != nil {
			return extensionStages, errors.Wrapf(err, "matching hook %q", namedHook.name)
		}
		if match {
			if config.Hooks == nil {
				config.Hooks = &rspec.Hooks{}
			}
			for _, stage := range namedHook.hook.Stages {
				switch stage {
				case "prestart":
					config.Hooks.Prestart = append(config.Hooks.Prestart, namedHook.hook.Hook)
				case "poststart":
					config.Hooks.Poststart = append(config.Hooks.Poststart, namedHook.hook.Hook)
				case "poststop":
					config.Hooks.Poststop = append(config.Hooks.Poststop, namedHook.hook.Hook)
				default:
					if !validStages[stage] {
						return extensionStages, fmt.Errorf("hook %q: unknown stage %q", namedHook.name, stage)
					}
					if extensionStages == nil {
						extensionStages = map[string][]rspec.Hook{}
					}
					extensionStages[stage] = append(extensionStages[stage], namedHook.hook.Hook)
				}
			}
		}
	}

	return extensionStages, nil
}

// remove remove a hook by name.
func (m *Manager) remove(hook string) (ok bool) {
	m.lock.Lock()
	defer m.lock.Unlock()
	_, ok = m.hooks[hook]
	if ok {
		delete(m.hooks, hook)
	}
	return ok
}

// add adds a hook by path
func (m *Manager) add(path string) (err error) {
	m.lock.Lock()
	defer m.lock.Unlock()
	hook, err := Read(path, m.extensionStages)
	if err != nil {
		return err
	}
	m.hooks[filepath.Base(path)] = hook
	return nil
}

// Len is part of the collate.Lister interface.
func (hooks namedHooks) Len() int {
	return len(hooks)
}

// Swap is part of the collate.Lister interface.
func (hooks namedHooks) Swap(i, j int) {
	hooks[i], hooks[j] = hooks[j], hooks[i]
}

// Bytes is part of the collate.Lister interface.
func (hooks namedHooks) Bytes(i int) []byte {
	return []byte(hooks[i].name)
}