README
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Conf-Syncer: sync your config files with etcd
Conf-Syncer is a little Go Program that helps keeping config files in sync with a Key Value store. Only etcd v3 is supported but adding other key-value store is just about implementing a simple interface.
Motivations
My TLS certs are fetched dynamically from Let's Encrypt and upgraded every three months. I need to keep these certs in sync between my load-balancer instances and using a distributed file storage was overkill (I'm running Kubernetes clusters on top of AWS and therefore don't have access to ReadManyWriteMany volumes... without deploying a Ceph cluster at least...).
This self-contained program can run on bare-metal or in VMs (using Docker or not) and plays pretty well as an init-container/sidecar container for my Ingress controllers in Kubernetes. The init-container simply pulls the config from the key-value store and dies, the sidecar container keeps the config in sync. If you don't need to be sure that the config files are there when the target container starts for the first time, the sidecar container alone should be just fine).
In the longer run, I'm trying to wrap this in a Kubernetes ThirdPartyResource (a sort of dynamic config map).
Building, Packaging and Distributing
You'll need docker and make in order to build the project, nothing else
(we're using a build container), just run make.
You can also build a container with make docker and ship it to a registry of
your choice with
DOCKER_IMAGE=my.registry.io/confsyncer DOCKER_TAG=v2 make docker-push
Finally, if you have docker-compose installed, you can get a dev. environment
with one etcd container reachable on localhost:20379 and a syncer container.
The command to run is make devenv.
Contributing
Contributions are always welcome :)
A containerized development environment based on docker-compose is available
with make devenv if you don't want to deal with installing dependencies. It
runs an etcd instance that listens on http://localhost:20379.
Every time you bring a change to your code, rerunning make devenv will rebuild
what's needed and update the dev. env. (thanks to the old magic of GNU make).
If you want to tail your syncer container's log after the rebuild, simply run
make devenv-probe.
All docker-compose commands will also work ;-)
Would you update dependencies in the glide.yaml, run make vendor-update to
update them. You can handle dependencies manually with glide.
KVStore fixtures
You can get some data in the etcd container by running make populate-etcd. It
should immediately synchronize the config with your disks.
Maintainers
- Étienne Lafarge <etienne.lafarge at gmail.com>
Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type ConfEvent ¶
type ConfEvent struct {
Key string
Content []byte
Type ConfEventType
}
ConfEvent describes a conf change event
type ConfEventType ¶
type ConfEventType int
ConfEventType discriminates config update event types (PUT and DELETE)
const ( ConfPut ConfEventType = iota ConfDelete )
Conf update event types
type ConfStore ¶
type ConfStore interface {
List() (data []ConfItem, err error)
Close() error
Updates() <-chan ConfEvent
Put(key string, value []byte) error
Delete(key string) error
SkipNext(key string)
}
ConfStore abstracts a config store (etcd, local disk...)
type DiskStore ¶
DiskStore implements a disk backed config store
func NewDiskStore ¶
NewDiskStore instantiates a new disk ConfigStore
type Etcd3Store ¶
Etcd3Store implements an etcd3-backed config store
func NewEtcd3Store ¶
func NewEtcd3Store(endpoint, prefix string) (cs *Etcd3Store, err error)
NewEtcd3Store creates a new etcd3 config store
func (*Etcd3Store) Delete ¶
func (cs *Etcd3Store) Delete(key string) error
Delete deletes a given key
func (*Etcd3Store) List ¶
func (cs *Etcd3Store) List() (data []ConfItem, err error)
List all conf from Etcd3
func (*Etcd3Store) Put ¶
func (cs *Etcd3Store) Put(key string, value []byte) error
Put puts a given value under a given key
func (*Etcd3Store) Updates ¶
func (cs *Etcd3Store) Updates() <-chan ConfEvent
Updates returns the ConfStore update channel
type Syncer ¶
type Syncer struct {
LocalStore ConfStore
RemoteStore ConfStore
// contains filtered or unexported fields
}
Syncer keeps a local config store in sync with a remote config stores
func (*Syncer) AddLocalConfToRemoteStore ¶
AddLocalConfToRemoteStore puts on the remote all the local config files that aren't already in there
func (*Syncer) KeepInSync ¶
func (s *Syncer) KeepInSync()
KeepInSync makes sure all config stores are kept in sync
func (*Syncer) PullFromRemote ¶
PullFromRemote pulls the config from the remote store without triggering any event. It's useful to initialize the config from the remote single source of truth.
Source Files
Directories