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resources: augeas: New resource

Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
pull/128/head
Julien Pivotto 4 years ago
parent
commit
bdb8368e89
No known key found for this signature in database GPG Key ID: 6758AB4EFE79EA8A
  1. 3
      .gitmodules
  2. 7
      docs/documentation.md
  3. 11
      examples/augeas1.yaml
  4. 2
      misc/make-deps.sh
  5. 307
      resources/augeas.go
  6. 30
      test/shell/augeas-1.sh
  7. 11
      test/shell/augeas-1.yaml
  8. 1
      vendor/honnef.co/go/augeas
  9. 1
      yamlgraph/gconfig.go

3
.gitmodules

@ -13,3 +13,6 @@
[submodule "vendor/github.com/purpleidea/go-systemd"]
path = vendor/github.com/purpleidea/go-systemd
url = https://github.com/purpleidea/go-systemd
[submodule "vendor/honnef.co/go/augeas"]
path = vendor/honnef.co/go/augeas
url = https://github.com/dominikh/go-augeas/

7
docs/documentation.md

@ -219,6 +219,7 @@ meta parameters aren't very useful when combined with certain resources, but
in general, it should be fairly obvious, such as when combining the `noop` meta
parameter with the [Noop](#Noop) resource.
* [Augeas](#Augeas): Manipulate files using augeas.
* [Exec](#Exec): Execute shell commands on the system.
* [File](#File): Manage files and directories.
* [Hostname](#Hostname): Manages the hostname on the system.
@ -231,6 +232,12 @@ parameter with the [Noop](#Noop) resource.
* [Timer](#Timer): Manage system systemd services.
* [Virt](#Virt): Manage virtual machines with libvirt.
### Augeas
The augeas resource uses [augeas](http://augeas.net/) commands to manipulate
files.
### Exec
The exec resource can execute commands on your system.

11
examples/augeas1.yaml

@ -0,0 +1,11 @@
---
graph: mygraph
resources:
augeas:
- name: sshd_config
lens: Sshd.lns
file: "/etc/ssh/sshd_config"
sets:
- path: X11Forwarding
value: no
edges:

2
misc/make-deps.sh

@ -27,10 +27,12 @@ fi
if [ ! -z "$YUM" ]; then
$sudo_command $YUM install -y libvirt-devel
$sudo_command $YUM install -y augeas-devel
fi
if [ ! -z "$APT" ]; then
$sudo_command $APT install -y libvirt-dev || true
$sudo_command $APT install -y libaugeas-dev || true
$sudo_command $APT install -y libpcap0.8-dev || true
fi

307
resources/augeas.go

@ -0,0 +1,307 @@
// Mgmt
// Copyright (C) 2013-2016+ James Shubin and the project contributors
// Written by James Shubin <james@shubin.ca> and the project contributors
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package resources
import (
"encoding/gob"
"fmt"
"log"
"os"
"strings"
"github.com/purpleidea/mgmt/event"
"github.com/purpleidea/mgmt/recwatch"
errwrap "github.com/pkg/errors"
// FIXME: we vendor go/augeas because master requires augeas 1.6.0
// and libaugeas-dev-1.6.0 is not yet available in a PPA.
"honnef.co/go/augeas"
)
func init() {
gob.Register(&AugeasRes{})
}
// AugeasRes is a resource that enables you to use the augeas resource.
// Currently only allows you to change simple files (e.g sshd_config).
type AugeasRes struct {
BaseRes `yaml:",inline"`
// File is the path to the file targetted by this resource.
// If specified, mgmt will watch that file.
File string `yaml:"file"`
// Lens is the lens used by this resource. If specified, mgmt
// will lower the augeas overhead by only loeading that lens.
Lens string `yaml:"lens"`
// Sets is a list of changes that will be applied to the file, in the form of
// ["path", "value"]. mgmt will run augeas.Get() before augeas.Set(), to
// prevent changing the file when it is not needed.
Sets []AugeasSet `yaml:"sets"`
recWatcher *recwatch.RecWatcher // used to watch the changed files
}
// AugeasSet represents a key/value pair of settings to be applied.
type AugeasSet struct {
Path string `yaml:"path"` // The relative path to the value to be changed.
Value string `yaml:"value"` // The value to be set on the given Path.
}
// NewAugeasRes is a constructor for this resource. It also calls Init() for you.
func NewAugeasRes(name string) (*AugeasRes, error) {
obj := &AugeasRes{
BaseRes: BaseRes{
Name: name,
},
}
return obj, obj.Init()
}
// Default returns some sensible defaults for this resource.
func (obj *AugeasRes) Default() Res {
return &AugeasRes{}
}
// Validate if the params passed in are valid data.
func (obj *AugeasRes) Validate() error {
if !strings.HasPrefix(obj.File, "/") {
return fmt.Errorf("File should start with a slash.")
}
if obj.Lens != "" && !strings.HasSuffix(obj.Lens, ".lns") {
return fmt.Errorf("Lens should have a .lns suffix.")
}
if (obj.Lens == "") != (obj.File == "") {
return fmt.Errorf("File and Lens must be specified together.")
}
return obj.BaseRes.Validate()
}
// Init initiates the resource.
func (obj *AugeasRes) Init() error {
obj.BaseRes.kind = "Augeas"
return obj.BaseRes.Init() // call base init, b/c we're overriding
}
// Watch is the primary listener for this resource and it outputs events.
// Taken from the File resource.
// FIXME: DRY - This is taken from the file resource
func (obj *AugeasRes) Watch(processChan chan *event.Event) error {
var err error
obj.recWatcher, err = recwatch.NewRecWatcher(obj.File, false)
if err != nil {
return err
}
defer obj.recWatcher.Close()
// notify engine that we're running
if err := obj.Running(processChan); err != nil {
return err // bubble up a NACK...
}
var send = false // send event?
var exit *error
for {
if obj.debug {
log.Printf("%s[%s]: Watching: %s", obj.Kind(), obj.GetName(), obj.File) // attempting to watch...
}
select {
case event, ok := <-obj.recWatcher.Events():
if !ok { // channel shutdown
return nil
}
if err := event.Error; err != nil {
return errwrap.Wrapf(err, "Unknown %s[%s] watcher error", obj.Kind(), obj.GetName())
}
if obj.debug { // don't access event.Body if event.Error isn't nil
log.Printf("%s[%s]: Event(%s): %v", obj.Kind(), obj.GetName(), event.Body.Name, event.Body.Op)
}
send = true
obj.StateOK(false) // dirty
case event := <-obj.Events():
if exit, send = obj.ReadEvent(event); exit != nil {
return *exit // exit
}
//obj.StateOK(false) // dirty // these events don't invalidate state
}
// do all our event sending all together to avoid duplicate msgs
if send {
send = false
obj.Event(processChan)
}
}
}
// checkApplySet runs CheckApply for one element of the AugeasRes.Set
func (obj *AugeasRes) checkApplySet(apply bool, ag *augeas.Augeas, set AugeasSet) (bool, error) {
fullpath := fmt.Sprintf("/files/%v/%v", obj.File, set.Path)
// We do not check for errors because errors are also thrown when
// the path does not exist.
if getValue, _ := ag.Get(fullpath); set.Value == getValue {
// The value is what we expect, return directly
return true, nil
}
if !apply {
// If noop, we can return here directly. We return with
// nil even if err is not nil because it does not mean
// there is an error.
return false, nil
}
if err := ag.Set(fullpath, set.Value); err != nil {
return false, errwrap.Wrapf(err, "augeas: error while setting value")
}
return false, nil
}
// CheckApply method for Augeas resource.
func (obj *AugeasRes) CheckApply(apply bool) (bool, error) {
log.Printf("%s[%s]: CheckApply: %s", obj.Kind(), obj.GetName(), obj.File)
// By default we do not set any option to augeas, we use the defaults.
opts := augeas.None
if obj.Lens != "" {
// if the lens is specified, we can speed up augeas by not
// loading everything. Without this option, augeas will try to
// read all the files it knows in the complete filesystem.
// e.g. to change /etc/ssh/sshd_config, it would load /etc/hosts, /etc/ntpd.conf, etc...
opts = augeas.NoModlAutoload
}
// Initiate augeas
ag, err := augeas.New("/", "", opts)
if err != nil {
return false, errwrap.Wrapf(err, "augeas: error while initializing")
}
defer ag.Close()
if obj.Lens != "" {
// If the lens is set, load the lens for the file we want to edit.
// We pick Xmgmt, as this name will not collide with any other lens name.
// We do not pick Mgmt as in the future there might be an Mgmt lens.
// https://github.com/hercules-team/augeas/wiki/Loading-specific-files
if err = ag.Set("/augeas/load/Xmgmt/lens", obj.Lens); err != nil {
return false, errwrap.Wrapf(err, "augeas: error while initializing lens")
}
if err = ag.Set("/augeas/load/Xmgmt/incl", obj.File); err != nil {
return false, errwrap.Wrapf(err, "augeas: error while initializing incl")
}
if err = ag.Load(); err != nil {
return false, errwrap.Wrapf(err, "augeas: error while loading")
}
}
checkOK := true
for _, set := range obj.Sets {
if setCheckOK, err := obj.checkApplySet(apply, &ag, set); err != nil {
return false, errwrap.Wrapf(err, "augeas: error during CheckApply of one Set")
} else if !setCheckOK {
checkOK = false
}
}
// If the state is correct or we can't apply, return early.
if checkOK || !apply {
return checkOK, nil
}
log.Printf("%s[%s]: changes needed, saving", obj.Kind(), obj.GetName())
if err = ag.Save(); err != nil {
return false, errwrap.Wrapf(err, "augeas: error while saving augeas values")
}
// FIXME: Workaround for https://github.com/dominikh/go-augeas/issues/13
// To be fixed upstream.
if obj.File != "" {
if _, err := os.Stat(obj.File); os.IsNotExist(err) {
return false, errwrap.Wrapf(err, "augeas: error: file does not exist")
}
}
return false, nil
}
// AugeasUID is the UID struct for AugeasRes.
type AugeasUID struct {
BaseUID
name string
}
// AutoEdges returns the AutoEdge interface. In this case no autoedges are used.
func (obj *AugeasRes) AutoEdges() AutoEdge {
return nil
}
// UIDs includes all params to make a unique identification of this object.
func (obj *AugeasRes) UIDs() []ResUID {
x := &AugeasUID{
BaseUID: BaseUID{name: obj.GetName(), kind: obj.Kind()},
name: obj.Name,
}
return []ResUID{x}
}
// GroupCmp returns whether two resources can be grouped together or not.
func (obj *AugeasRes) GroupCmp(r Res) bool {
return false // Augeas commands can not be grouped together.
}
// Compare two resources and return if they are equivalent.
func (obj *AugeasRes) Compare(res Res) bool {
switch res.(type) {
// we can only compare AugeasRes to others of the same resource
case *AugeasRes:
res := res.(*AugeasRes)
if !obj.BaseRes.Compare(res) { // call base Compare
return false
}
if obj.Name != res.Name {
return false
}
default:
return false
}
return true
}
// UnmarshalYAML is the custom unmarshal handler for this struct.
// It is primarily useful for setting the defaults.
func (obj *AugeasRes) UnmarshalYAML(unmarshal func(interface{}) error) error {
type rawRes AugeasRes // indirection to avoid infinite recursion
def := obj.Default() // get the default
res, ok := def.(*AugeasRes) // put in the right format
if !ok {
return fmt.Errorf("could not convert to AugeasRes")
}
raw := rawRes(*res) // convert; the defaults go here
if err := unmarshal(&raw); err != nil {
return err
}
*obj = AugeasRes(raw) // restore from indirection with type conversion!
return nil
}

30
test/shell/augeas-1.sh

@ -0,0 +1,30 @@
#!/bin/bash -e
if env | grep -q -e '^TRAVIS=true$'; then
# inotify doesn't seem to work properly on travis
echo "Travis and Jenkins give wonky results here, skipping test!"
exit
fi
mkdir -p "${MGMT_TMPDIR}"
> "${MGMT_TMPDIR}"sshd_config
# run empty graph, with prometheus support
timeout --kill-after=20s 15s ./mgmt run --tmp-prefix --yaml=augeas-1.yaml &
pid=$!
sleep 5s # let it converge
grep "X11Forwarding no" "${MGMT_TMPDIR}"sshd_config
sed -i "s/no/yes/" "${MGMT_TMPDIR}"sshd_config
grep "X11Forwarding yes" "${MGMT_TMPDIR}"sshd_config
sleep 3 # Augeas is slow
grep "X11Forwarding no" "${MGMT_TMPDIR}"sshd_config
killall -SIGINT mgmt # send ^C to exit mgmt
wait $pid # get exit status
exit $?

11
test/shell/augeas-1.yaml

@ -0,0 +1,11 @@
---
graph: mygraph
resources:
augeas:
- name: sshd_test
lens: Sshd.lns
file: "/tmp/mgmt/sshd_config"
sets:
- path: X11Forwarding
value: no
edges:

1
vendor/honnef.co/go/augeas

@ -0,0 +1 @@
Subproject commit 1e2ddf1bad06f9e1cfdd62dd909c4fcb7f82e114

1
yamlgraph/gconfig.go

@ -56,6 +56,7 @@ type Edge struct {
// Resources is the data structure of the set of resources.
type Resources struct {
// in alphabetical order
Augeas []*resources.AugeasRes `yaml:"augeas"`
Exec []*resources.ExecRes `yaml:"exec"`
File []*resources.FileRes `yaml:"file"`
Hostname []*resources.HostnameRes `yaml:"hostname"`

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