negasus/rplx

Golang library for multi-master replication integer variables with TTL

RPLX

Pronounced as Replix

Golang library for multi master replication integer variables with TTL support

todo

Usage examples

func main() {
	r = rplx.New(
		rplx.WithRemoteNodesProvider(remoteNodes()),
	)

	ln, err := net.Listen("tcp4", "127.0.0.1:3001")  

	if err != nil {
		panic(err)
	}

	if err := r.StartReplicationServer(ln); err != nil {
		panic(err)
	}
}

func remoteNodes() []*rplx.RemoteNodeOption {
    nodes := make([]*rplx.RemoteNodeOption, 0)

    nodes = append(nodes, &rplx.DefaultRemoteNodeOption("127.0.0.1:3002")) 

    return nodes
}

Also see example in test folder

Metrics

Creates Rplx instance with option WithMetrics() will registers prometheus metrics.

Name	Type	Description
rplx_variables_got	Counter Vector	Stores received variables count with fields: 'remote_node_id'
rplx_variables_sent	Counter Vector	Stores sent variables count with fields: 'remote_node_id'
rplx_variables_sent_response_codes	Counter Vector	Stores response code, received while variable sent with fields: 'remote_node_id', 'code'
rplx_variables_sent_duration	Histogram Vector	Stores duration for Sync Request, fields: 'remote_node_id', 'code'

Also included metrics from package github.com/grpc-ecosystem/go-grpc-prometheus

Public API

Get

Get(name string) (int64, error)

Returns variable value or error, if variable expired or not exists

Errors:

• ErrVariableNotExists
• ErrVariableExpired

Delete

Delete(name string) error

Delete variable

Errors:

• ErrVariableNotExists

By fact this method sets TTL for variable to Now - second, send this info to replication and remove from local cache

UpdateTTL

UpdateTTL(name string, ttl time.Time) error

Update TTL for variable

Errors:

• ErrVariableNotExists

Upsert

Upsert(name string, delta int64)

Update variable value on provided delta, or create new variable, if not exists

All

All() (notExpired map[string]int64, expired map[string]int64)

Returns two maps, where variable name as map item key and variable value as map item value

First return param contains not expires variables. Second param contains expired (while not garbage colleced) variables

Run integration tests

docker-compose up -d
docker build -t client -f ./test/client/Dockerfile .
docker run --rm --net host client
docker-compose down -v

Additional

• README.RUS.md

rplx's Issues

Implement compacting values from not exists nodes

Save memory proposal.

If many nodes leaved cluster (and possible joined to cluster with new ID), its values with old IDs will be take memory forever.

Consider compacting proccess for orphans values to one virtual node value.

For example. Node2 and greater are orphans

Var1:
node1: 100
node2: 200
node3: 300
node4: 400

After compacting

Var1:
node1: 200
SpecialVirtualNode: 200+300+400

Add prometheus metrics

Add prometheus metrics

• count of incoming/outcomping sync requests
• size of sync requiests
• count of remote nodes
  etc.

Possible write to closed channel

While closing channel in node.go#105 close(n.syncQueue), possible write to channel in node_sync.go#16 case n.syncQueue <- struct{}{}: