commit 1293dd04446ba908242e71233e51851d28ffc631
Author: Mikaël Cluseau <mcluseau@isi.nc>
Date:   Tue Jun 12 20:52:20 2018 +1100

    Initial commit

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..7e3fbe6
--- /dev/null
+++ b/README.md
@@ -0,0 +1 @@
+Common go packages used in Direktil.
diff --git a/cas/cas.go b/cas/cas.go
new file mode 100644
index 0000000..8ae24af
--- /dev/null
+++ b/cas/cas.go
@@ -0,0 +1,27 @@
+// Package cas provides a content-accessible storage implementation
+package cas
+
+import (
+	"io"
+	"time"
+)
+
+// Content is an item's content.
+type Content interface {
+	io.Reader
+	io.Seeker
+	io.Closer
+}
+
+// Meta is an item's metadata.
+type Meta interface {
+	Size() int64
+	ModTime() time.Time
+}
+
+// Store is a CAS store.
+type Store interface {
+	GetOrCreate(tag, item string, create func(io.Writer) error) (content Content, meta Meta, err error)
+	Tags() (tags []string, err error)
+	Remove(tag string) error
+}
diff --git a/cas/dir-store.go b/cas/dir-store.go
new file mode 100644
index 0000000..ed7c8df
--- /dev/null
+++ b/cas/dir-store.go
@@ -0,0 +1,112 @@
+package cas
+
+import (
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"sync"
+)
+
+// NewDirStore create a new store backed by the given directory.
+func NewDir(path string) *DirStore {
+	return &DirStore{
+		path: path,
+	}
+}
+
+// DirStore is a Store backed by a directory.
+type DirStore struct {
+	path  string
+	mutex sync.Mutex
+}
+
+var _ Store = &DirStore{}
+
+// GetOrCreate is part of the Store interface.
+func (s *DirStore) GetOrCreate(tag, item string, create func(io.Writer) error) (content Content, meta Meta, err error) {
+	fullPath := filepath.Join(s.path, tag, item)
+
+	f, err := os.Open(fullPath)
+	if err != nil {
+		s.mutex.Lock()
+		defer s.mutex.Unlock()
+
+		f, err = os.Open(fullPath)
+	}
+
+	if err != nil {
+		if !os.IsNotExist(err) {
+			return
+		}
+
+		err = os.MkdirAll(filepath.Dir(fullPath), 0700)
+		if err != nil {
+			return
+		}
+
+		var out *os.File
+		out, err = os.OpenFile(fullPath+".part", os.O_CREATE|os.O_TRUNC|os.O_WRONLY|os.O_EXCL, 0600)
+		if err != nil {
+			return
+		}
+
+		err = create(out)
+
+		out.Close()
+
+		if err != nil {
+			os.Remove(fullPath + ".part")
+			return
+		}
+
+		if err = os.Rename(fullPath+".part", fullPath); err != nil {
+			return
+		}
+
+		f, err = os.Open(fullPath)
+		if err != nil {
+			return
+		}
+	}
+
+	stat, err := os.Stat(fullPath)
+	if err != nil {
+		return
+	}
+
+	return f, stat, nil
+}
+
+// Tags is part of the Store interface.
+func (s *DirStore) Tags() (tags []string, err error) {
+	entries, err := ioutil.ReadDir(s.path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return []string{}, nil
+		}
+		return
+	}
+
+	tags = make([]string, 0, len(entries))
+	for _, entry := range entries {
+		if !entry.IsDir() {
+			continue
+		}
+
+		name := entry.Name()
+
+		if name[0] == '.' {
+			continue
+		}
+
+		tags = append(tags, name)
+	}
+
+	return
+}
+
+// Remove is part of the Store interface.
+func (s *DirStore) Remove(tag string) error {
+	return os.RemoveAll(filepath.Join(s.path, tag))
+}
diff --git a/clustersconfig/clustersconfig.go b/clustersconfig/clustersconfig.go
new file mode 100644
index 0000000..283167c
--- /dev/null
+++ b/clustersconfig/clustersconfig.go
@@ -0,0 +1,209 @@
+package clustersconfig
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net"
+	"strings"
+	"text/template"
+
+	yaml "gopkg.in/yaml.v2"
+)
+
+type Config struct {
+	Hosts      []*Host
+	Groups     []*Group
+	Clusters   []*Cluster
+	Configs    []*Template
+	StaticPods []*Template `yaml:"static_pods"`
+}
+
+func FromBytes(data []byte) (*Config, error) {
+	config := &Config{}
+	if err := yaml.Unmarshal(data, config); err != nil {
+		return nil, err
+	}
+	return config, nil
+}
+
+func FromFile(path string) (*Config, error) {
+	ba, err := ioutil.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+
+	return FromBytes(ba)
+}
+
+func (c *Config) Host(name string) *Host {
+	for _, host := range c.Hosts {
+		if host.Name == name {
+			return host
+		}
+	}
+	return nil
+}
+
+func (c *Config) HostByIP(ip string) *Host {
+	for _, host := range c.Hosts {
+		if host.IP == ip {
+			return host
+		}
+
+		for _, otherIP := range host.IPs {
+			if otherIP == ip {
+				return host
+			}
+		}
+	}
+	return nil
+}
+
+func (c *Config) HostByMAC(mac string) *Host {
+	// a bit of normalization
+	mac = strings.Replace(strings.ToLower(mac), "-", ":", -1)
+
+	for _, host := range c.Hosts {
+		if strings.ToLower(host.MAC) == mac {
+			return host
+		}
+	}
+
+	return nil
+}
+
+func (c *Config) Group(name string) *Group {
+	for _, group := range c.Groups {
+		if group.Name == name {
+			return group
+		}
+	}
+	return nil
+}
+
+func (c *Config) Cluster(name string) *Cluster {
+	for _, cluster := range c.Clusters {
+		if cluster.Name == name {
+			return cluster
+		}
+	}
+	return nil
+}
+
+func (c *Config) ConfigTemplate(name string) *Template {
+	for _, cfg := range c.Configs {
+		if cfg.Name == name {
+			return cfg
+		}
+	}
+	return nil
+}
+
+func (c *Config) StaticPodsTemplate(name string) *Template {
+	for _, s := range c.StaticPods {
+		if s.Name == name {
+			return s
+		}
+	}
+	return nil
+}
+
+func (c *Config) SaveTo(path string) error {
+	ba, err := yaml.Marshal(c)
+	if err != nil {
+		return err
+	}
+
+	return ioutil.WriteFile(path, ba, 0600)
+}
+
+type Template struct {
+	Name     string
+	Template string
+
+	parsedTemplate *template.Template
+}
+
+func (t *Template) Execute(wr io.Writer, data interface{}, extraFuncs map[string]interface{}) error {
+	if t.parsedTemplate == nil {
+		var templateFuncs = map[string]interface{}{
+			"indent": func(indent, s string) (indented string) {
+				indented = indent + strings.Replace(s, "\n", "\n"+indent, -1)
+				return
+			},
+		}
+
+		for name, f := range extraFuncs {
+			templateFuncs[name] = f
+		}
+
+		tmpl, err := template.New("tmpl").
+			Funcs(templateFuncs).
+			Parse(t.Template)
+		if err != nil {
+			return err
+		}
+		t.parsedTemplate = tmpl
+	}
+
+	return t.parsedTemplate.Execute(wr, data)
+}
+
+// Host represents a host served by this server.
+type Host struct {
+	Name    string
+	MAC     string
+	IP      string
+	IPs     []string
+	Cluster string
+	Group   string
+	Vars    Vars
+}
+
+// Group represents a group of hosts and provides their configuration.
+type Group struct {
+	Name       string
+	Master     bool
+	IPXE       string
+	Kernel     string
+	Initrd     string
+	Config     string
+	StaticPods string `yaml:"static_pods"`
+	Versions   map[string]string
+	Vars       Vars
+}
+
+// Vars store user-defined key-values
+type Vars map[string]interface{}
+
+// Cluster represents a cluster of hosts, allowing for cluster-wide variables.
+type Cluster struct {
+	Name    string
+	Domain  string
+	Subnets struct {
+		Services string
+		Pods     string
+	}
+	Vars Vars
+}
+
+func (c *Cluster) KubernetesSvcIP() net.IP {
+	return c.NthSvcIP(1)
+}
+
+func (c *Cluster) DNSSvcIP() net.IP {
+	return c.NthSvcIP(2)
+}
+
+func (c *Cluster) NthSvcIP(n byte) net.IP {
+	_, cidr, err := net.ParseCIDR(c.Subnets.Services)
+	if err != nil {
+		panic(fmt.Errorf("Invalid services CIDR: %v", err))
+	}
+
+	ip := cidr.IP
+	ip[len(ip)-1] += n
+
+	return ip
+}
diff --git a/clustersconfig/dir.go b/clustersconfig/dir.go
new file mode 100644
index 0000000..63c57d9
--- /dev/null
+++ b/clustersconfig/dir.go
@@ -0,0 +1,129 @@
+package clustersconfig
+
+import (
+	"io/ioutil"
+	"path"
+	"path/filepath"
+	"strings"
+
+	yaml "gopkg.in/yaml.v2"
+)
+
+func FromDir(dirPath string) (*Config, error) {
+	config := &Config{}
+
+	store := dirStore{dirPath}
+	load := func(dir, name string, out interface{}) error {
+		ba, err := store.Get(path.Join(dir, name))
+		if err != nil {
+			return err
+		}
+		return yaml.Unmarshal(ba, out)
+	}
+
+	// load clusters
+	names, err := store.List("clusters")
+	if err != nil {
+		return nil, err
+	}
+
+	for _, name := range names {
+		cluster := &Cluster{Name: name}
+		if err := load("clusters", name, cluster); err != nil {
+			return nil, err
+		}
+
+		config.Clusters = append(config.Clusters, cluster)
+	}
+
+	// load groups
+	names, err = store.List("groups")
+	if err != nil {
+		return nil, err
+	}
+
+	for _, name := range names {
+		o := &Group{Name: name}
+		if err := load("groups", name, o); err != nil {
+			return nil, err
+		}
+
+		config.Groups = append(config.Groups, o)
+	}
+
+	// load hosts
+	names, err = store.List("hosts")
+	if err != nil {
+		return nil, err
+	}
+
+	for _, name := range names {
+		o := &Host{Name: name}
+		if err := load("hosts", name, o); err != nil {
+			return nil, err
+		}
+
+		config.Hosts = append(config.Hosts, o)
+	}
+
+	// load config templates
+	loadTemplates := func(dir string, templates *[]*Template) error {
+		names, err = store.List(dir)
+		if err != nil {
+			return err
+		}
+
+		for _, name := range names {
+			ba, err := store.Get(path.Join(dir, name))
+			if err != nil {
+				return err
+			}
+
+			o := &Template{Name: name, Template: string(ba)}
+
+			*templates = append(*templates, o)
+		}
+
+		return nil
+	}
+
+	if err := loadTemplates("configs", &config.Configs); err != nil {
+		return nil, err
+	}
+	if err := loadTemplates("static-pods", &config.StaticPods); err != nil {
+		return nil, err
+	}
+
+	return config, nil
+}
+
+type dirStore struct {
+	path string
+}
+
+// Names is part of the kvStore interface
+func (b *dirStore) List(prefix string) ([]string, error) {
+	files, err := filepath.Glob(filepath.Join(b.path, filepath.Join(path.Split(prefix)), "*.yaml"))
+	if err != nil {
+		return nil, err
+	}
+
+	names := make([]string, 0, len(files))
+	for _, f := range files {
+		f2 := strings.TrimSuffix(f, ".yaml")
+		f2 = filepath.Base(f2)
+
+		if f2[0] == '.' { // ignore hidden files
+			continue
+		}
+
+		names = append(names, f2)
+	}
+
+	return names, nil
+}
+
+// Load is part of the DataBackend interface
+func (b *dirStore) Get(key string) ([]byte, error) {
+	return ioutil.ReadFile(filepath.Join(b.path, filepath.Join(path.Split(key))+".yaml"))
+}
diff --git a/color/colors.go b/color/colors.go
new file mode 100644
index 0000000..0058256
--- /dev/null
+++ b/color/colors.go
@@ -0,0 +1,36 @@
+package color
+
+import "io"
+
+const (
+	None  Color = ""
+	Reset Color = "\033[0m"
+	Bold  Color = "\033[1m"
+
+	Red     Color = "\033[91m"
+	Green   Color = "\033[92m"
+	Yellow  Color = "\033[93m"
+	Blue    Color = "\033[94m"
+	Magenta Color = "\033[95m"
+	Cyan    Color = "\033[96m"
+	White   Color = "\033[97m"
+
+	// Aligned versions (yes, I'm like that)
+
+	Red____ Color = Red
+	Green__ Color = Green
+	Yellow_ Color = Yellow
+	Blue___ Color = Blue
+	Cyan___ Color = Cyan
+	White__ Color = White
+
+	// Extra colors
+	DarkGreen Color = "\033[32m"
+	DarkGray  Color = "\033[90m"
+)
+
+type Color string
+
+func Write(out io.Writer, color Color, message string) {
+	out.Write([]byte(string(color) + message + string(Reset)))
+}
diff --git a/config/config.go b/config/config.go
new file mode 100644
index 0000000..2ebf0a1
--- /dev/null
+++ b/config/config.go
@@ -0,0 +1,102 @@
+package config
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	yaml "gopkg.in/yaml.v2"
+)
+
+// Config represent this system's configuration
+type Config struct {
+	Vars []VarDefault
+
+	Layers  []string
+	Modules []string
+
+	RootUser struct {
+		PasswordHash   string   `yaml:"password_hash"`
+		AuthorizedKeys []string `yaml:"authorized_keys"`
+	} `yaml:"root_user"`
+
+	Storage StorageConfig
+
+	Groups []GroupDef
+	Users  []UserDef
+
+	Files []FileDef
+
+	Networks []NetworkDef
+}
+
+type VarDefault struct {
+	Name    string
+	Default string
+}
+
+type StorageConfig struct {
+	UdevMatch     string   `yaml:"udev_match"`
+	RemoveVolumes []string `yaml:"remove_volumes"`
+	Volumes       []VolumeDef
+}
+
+type VolumeDef struct {
+	Name    string
+	Size    string
+	Extents string
+	FS      string
+	Mount   struct {
+		Path    string
+		Options string
+	}
+}
+
+type GroupDef struct {
+	Name string
+	Gid  int
+}
+
+type UserDef struct {
+	Name string
+	Gid  int
+	Uid  int
+}
+
+type FileDef struct {
+	Path    string
+	Mode    os.FileMode
+	Content string
+	Secret  string
+}
+
+type NetworkDef struct {
+	Match struct {
+		All  bool
+		Name string
+		Ping *struct {
+			Source  string
+			Target  string
+			Count   int
+			Timeout int
+		}
+	}
+	Optional bool
+	Script   string
+}
+
+func Load(file string) (config *Config, err error) {
+	config = &Config{}
+
+	configData, err := ioutil.ReadFile(file)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read %s: %v", file, err)
+	}
+
+	err = yaml.Unmarshal(configData, config)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse %s: %v", file, err)
+	}
+
+	return
+}
diff --git a/log/compress.go b/log/compress.go
new file mode 100644
index 0000000..37a0366
--- /dev/null
+++ b/log/compress.go
@@ -0,0 +1,52 @@
+package log
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+
+	"github.com/ulikunitz/xz"
+)
+
+func compress(path string) {
+	in, err := os.Open(path)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "compress %s: failed to open: %v", path, err)
+		return
+	}
+
+	defer in.Close()
+
+	outPath := filepath.Join(filepath.Dir(path), "archives", filepath.Base(path)+".xz")
+
+	os.MkdirAll(filepath.Dir(outPath), 0700)
+
+	out, err := os.Create(outPath)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "compress %s: failed to create target: %v", path, err)
+		return
+	}
+
+	defer out.Close()
+
+	w, err := xz.NewWriter(out)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "compress %s: failed to create writer: %v", path, err)
+		return
+	}
+
+	if _, err := io.Copy(w, in); err != nil {
+		fmt.Fprintf(os.Stderr, "compress %s: write failed: %v", path, err)
+		return
+	}
+
+	if err := w.Close(); err != nil {
+		fmt.Fprintf(os.Stderr, "compress %s: close failed: %v", path, err)
+		return
+	}
+
+	if err := os.Remove(path); err != nil {
+		fmt.Fprintf(os.Stderr, "compress %s: failed to remove source: %v", path, err)
+	}
+}
diff --git a/log/entry.go b/log/entry.go
new file mode 100644
index 0000000..9c96938
--- /dev/null
+++ b/log/entry.go
@@ -0,0 +1,119 @@
+package log
+
+import (
+	"encoding/base32"
+	"fmt"
+	"io"
+	"time"
+)
+
+type Entry struct {
+	Time  time.Time
+	Taint Taint
+	Data  []byte
+}
+
+// WriteTo writes this log entry to w.
+// Automatically appends a new line if it's not already present to
+// get an easy to read log.
+func (e Entry) WriteTo(w io.Writer) (n int64, err error) {
+	l := len(e.Data)
+	t := e.Time.UnixNano()
+
+	flags := byte(0)
+	appendNL := e.Data[len(e.Data)-1] != '\n'
+
+	if appendNL {
+		flags |= AppendNL
+	}
+
+	b := []byte{
+		flags,
+		byte(e.Taint),
+		byte(l >> 16 & 0xff),
+		byte(l >> 8 & 0xff),
+		byte(l >> 0 & 0xff),
+		byte(t >> 56 & 0xff),
+		byte(t >> 48 & 0xff),
+		byte(t >> 40 & 0xff),
+		byte(t >> 32 & 0xff),
+		byte(t >> 24 & 0xff),
+		byte(t >> 16 & 0xff),
+		byte(t >> 8 & 0xff),
+		byte(t >> 0 & 0xff),
+	}
+
+	// the binary part is b32 encoded. Obscure but still readable in text mode.
+	enc := base32.StdEncoding
+
+	headerLen := enc.EncodedLen(len(b))
+	baLen := headerLen + len(e.Data)
+	if appendNL {
+		baLen++
+	}
+	ba := make([]byte, baLen)
+	enc.Encode(ba, b)
+
+	copy(ba[headerLen:], e.Data)
+
+	if appendNL {
+		ba[baLen-1] = '\n'
+	}
+
+	nw, err := w.Write(ba)
+	return int64(nw), err
+}
+
+// ReadFrom reads the next entry from r, updating this entry.
+func (e *Entry) ReadFrom(r io.Reader) (n int64, err error) {
+	enc := base32.StdEncoding
+
+	const L = 1 + 1 + 3 + 8
+	b := make([]byte, L)
+	ba := make([]byte, enc.EncodedLen(L))
+
+	nr, err := r.Read(ba)
+	if err != nil {
+		return int64(nr), err
+	}
+	fmt.Println(string(ba))
+
+	enc.Decode(b, ba)
+	fmt.Println(b)
+
+	p := 0
+	flags := b[p]
+	p++
+
+	e.Taint = Taint(b[p])
+	p++
+
+	l := int32(0)
+	for i := 0; i < 3; i++ {
+		l = l<<8 | int32(b[p])
+		p++
+	}
+
+	readLen := l
+	if flags|AppendNL != 0 {
+		readLen++
+	}
+
+	t := int64(0)
+	for i := 0; i < 8; i++ {
+		t = t<<8 | int64(b[p])
+		p++
+	}
+	e.Time = time.Unix(0, t)
+
+	data := make([]byte, readLen)
+	m, err := r.Read(data)
+	n += int64(m)
+	if err != nil {
+		return n, err
+	}
+
+	e.Data = data[:l]
+
+	return n, nil
+}
diff --git a/log/entry_test.go b/log/entry_test.go
new file mode 100644
index 0000000..9f8cba4
--- /dev/null
+++ b/log/entry_test.go
@@ -0,0 +1,38 @@
+package log
+
+import (
+	"bytes"
+	"testing"
+	"time"
+)
+
+func TestEncode(t *testing.T) {
+	l1 := Entry{time.Now(), Normal, []byte("test entry")}
+	l2 := Entry{}
+
+	buf := &bytes.Buffer{}
+	l1.WriteTo(buf)
+
+	t.Log(buf.String())
+
+	_, err := l2.ReadFrom(buf)
+	if err != nil {
+		t.Error("read error: ", err)
+	}
+
+	if l1.Taint != l2.Taint {
+		t.Errorf("wrong taint: %v != %v", l1.Taint, l2.Taint)
+	}
+
+	if l1.Time.UnixNano() != l2.Time.UnixNano() {
+		t.Errorf("wrong time: %v != %v", l1.Time, l2.Time)
+	}
+
+	if !bytes.Equal(l1.Data, l2.Data) {
+		t.Errorf("wrong data: %q != %q", string(l1.Data), string(l2.Data))
+	}
+
+	if l := len(buf.Bytes()); l > 0 {
+		t.Errorf("%d bytes not read", l)
+	}
+}
diff --git a/log/log.go b/log/log.go
new file mode 100644
index 0000000..005e113
--- /dev/null
+++ b/log/log.go
@@ -0,0 +1,244 @@
+package log
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"sync"
+	"time"
+
+	"novit.nc/direktil/src/pkg/color"
+)
+
+const (
+	// AppendNL indicates that a forced '\n' is added.
+	AppendNL byte = 1
+)
+
+var (
+	logs  = map[string]*Log{}
+	mutex = sync.Mutex{}
+
+	logOutputEnabled = false
+)
+
+// Log is a log target
+type Log struct {
+	name string
+
+	l           sync.Mutex
+	writeToFile bool
+
+	console io.Writer
+	pending []Entry
+	out     *os.File
+	outPath string
+}
+
+func Get(name string) *Log {
+	mutex.Lock()
+	defer mutex.Unlock()
+
+	if log, ok := logs[name]; ok {
+		return log
+	}
+
+	log := &Log{
+		name:    name,
+		pending: make([]Entry, 0),
+	}
+
+	if logOutputEnabled {
+		log.enableFileOutput()
+	}
+
+	logs[name] = log
+
+	return log
+}
+
+// EnableFiles flushes current logs to files, and enables output to files.
+func EnableFiles() {
+	mutex.Lock()
+	defer mutex.Unlock()
+
+	if logOutputEnabled {
+		return
+	}
+
+	for _, log := range logs {
+		// we'll let the kernel optimize, just do it all parallel
+		go log.enableFileOutput()
+	}
+
+	logOutputEnabled = true
+}
+
+// DisableFiles flushes and closes current logs files, and disables output to files.
+func DisableFiles() {
+	mutex.Lock()
+	defer mutex.Unlock()
+
+	if !logOutputEnabled {
+		return
+	}
+
+	for _, log := range logs {
+		// we'll let the kernel optimize, just do it all parallel
+		go log.disableFileOutput()
+	}
+
+	logOutputEnabled = false
+}
+
+func (l *Log) enableFileOutput() {
+	l.l.Lock()
+	defer l.l.Unlock()
+
+	for _, e := range l.pending {
+		if err := l.writeEntry(e); err != nil {
+			l.emergencyLog(e, err)
+		}
+	}
+	l.writeToFile = true
+}
+
+func (l *Log) disableFileOutput() {
+	l.l.Lock()
+	defer l.l.Unlock()
+
+	if l.out != nil {
+		l.out.Close()
+	}
+
+	l.writeToFile = false
+}
+
+func (l *Log) SetConsole(console io.Writer) {
+	l.console = console
+}
+
+// StreamLines will copy the input line by line as log entries.
+func (l *Log) StreamLines(r io.Reader) {
+	in := bufio.NewReader(r)
+	for {
+		line, err := in.ReadBytes('\n')
+		if err != nil {
+			if err != io.EOF {
+				fmt.Fprintf(os.Stderr, "log %s: read lines failed: %v\n", l.name, err)
+				time.Sleep(1 * time.Second)
+			}
+			return
+		}
+		l.Write(line)
+	}
+}
+
+// Print to this log.
+func (l *Log) Print(v ...interface{}) {
+	fmt.Fprint(l, v...)
+}
+
+// Printf to this log.
+func (l *Log) Printf(pattern string, v ...interface{}) {
+	fmt.Fprintf(l, pattern, v...)
+}
+
+// Taint is Print to this log with a taint.
+func (l *Log) Taint(taint Taint, v ...interface{}) {
+	l.append(taint, []byte(fmt.Sprint(v...)))
+}
+
+// Taintf is Printf to this log with a taint.
+func (l *Log) Taintf(taint Taint, pattern string, v ...interface{}) {
+	l.append(taint, []byte(fmt.Sprintf(pattern, v...)))
+}
+
+func (l *Log) append(taint Taint, data []byte) {
+	// we serialize writes
+	l.l.Lock()
+	defer l.l.Unlock()
+
+	e := Entry{
+		Time:  time.Now(),
+		Taint: taint,
+		Data:  data,
+	}
+
+	console := l.console
+	if console != nil {
+		buf := &bytes.Buffer{}
+		buf.WriteString(string(color.DarkGreen))
+		buf.WriteString(e.Time.Format("2006/01/02 15:04:05.000 "))
+		buf.WriteString(string(color.Reset))
+		buf.WriteString(string(e.Taint.Color()))
+		buf.Write(data)
+		if data[len(data)-1] != '\n' {
+			buf.Write([]byte{'\n'})
+		}
+		buf.WriteString(string(color.Reset))
+
+		buf.WriteTo(console)
+	}
+
+	if !l.writeToFile {
+		l.pending = append(l.pending, e)
+		// TODO if len(pending) > maxPending { pending = pending[len(pending)-underMaxPending:] }
+		// or use a ring
+		return
+	}
+
+	if err := l.writeEntry(e); err != nil {
+		l.emergencyLog(e, err)
+	}
+}
+
+func (l *Log) emergencyLog(entry Entry, err error) {
+	fmt.Fprintf(os.Stderr, "log %s: failed to write entry: %v\n  -> lost entry: ", l.name, err)
+	entry.WriteTo(os.Stderr)
+}
+
+// Write is part of the io.Writer interface.
+func (l *Log) Write(b []byte) (n int, err error) {
+	l.append(Normal, b)
+	return len(b), nil
+}
+
+func (l *Log) writeEntry(e Entry) (err error) {
+	path := fmt.Sprintf("/var/log/%s.%s.log",
+		l.name, e.Time.Truncate(time.Hour).Format(time.RFC3339))
+
+	currentPath := fmt.Sprintf("/var/log/%s.log", l.name)
+
+	if l.outPath != path {
+		if l.out != nil {
+			if err := l.out.Close(); err != nil {
+				fmt.Fprintf(os.Stderr, "log %s: failed to close output: %v\n", l.name, err)
+			}
+			os.Remove(currentPath)
+			go compress(l.outPath)
+		}
+		l.out = nil
+		l.outPath = ""
+	}
+
+	if l.out == nil {
+		l.out, err = os.OpenFile(path, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0640)
+		if err != nil {
+			return
+		}
+
+		l.outPath = path
+
+		os.Remove(currentPath)
+		if err := os.Symlink(path, currentPath); err != nil {
+			fmt.Fprintf(os.Stderr, "failed to symlink %s.log: %v\n", l.name, err)
+		}
+	}
+
+	_, err = e.WriteTo(l.out)
+
+	return
+}
diff --git a/log/taint.go b/log/taint.go
new file mode 100644
index 0000000..525ab1e
--- /dev/null
+++ b/log/taint.go
@@ -0,0 +1,33 @@
+package log
+
+import (
+	"novit.nc/direktil/src/pkg/color"
+)
+
+const (
+	Normal Taint = iota
+	Info
+	Warning
+	Error
+	Fatal
+	OK
+)
+
+type Taint byte
+
+func (t Taint) Color() color.Color {
+	switch t {
+	case Info:
+		return color.Blue
+	case Warning:
+		return color.Yellow
+	case Error:
+		return color.Red
+	case Fatal:
+		return color.Magenta
+	case OK:
+		return color.Green
+	default:
+		return color.None
+	}
+}
diff --git a/sysfs/sysfs.go b/sysfs/sysfs.go
new file mode 100644
index 0000000..589d41b
--- /dev/null
+++ b/sysfs/sysfs.go
@@ -0,0 +1,55 @@
+package sysfs
+
+import (
+	"io/ioutil"
+	"log"
+	"path/filepath"
+	"strings"
+)
+
+// DeviceByProperty lists the devices where a given property=value filters match.
+func DeviceByProperty(class string, filters ...string) []string {
+	files, err := filepath.Glob("/sys/class/" + class + "/*/uevent")
+	if err != nil {
+		log.Print("list devices failed: ", err)
+		return nil
+	}
+
+	filtered := make([]string, 0)
+
+filesLoop:
+	for _, file := range files {
+		ba, err := ioutil.ReadFile(file)
+		if err != nil {
+			log.Print("reading ", file, " failed: ", err)
+			continue
+		}
+
+		values := strings.Split(strings.TrimSpace(string(ba)), "\n")
+
+		devName := ""
+		for _, value := range values {
+			if strings.HasPrefix(value, "DEVNAME=") {
+				devName = value[len("DEVNAME="):]
+			}
+		}
+
+		for _, filter := range filters {
+			found := false
+			for _, value := range values {
+				if filter == value {
+					found = true
+					break
+				}
+			}
+
+			if !found {
+				continue filesLoop
+			}
+		}
+
+		filtered = append(filtered, devName)
+	}
+
+	return filtered
+}