feat: add static, dns discovery providers

README.md

@@ -1,3 +1,59 @@
 # Go-KV
 
-Simple Distributed in-memory key/value store. 
+[![GitHub Actions Workflow Status](https://img.shields.io/github/actions/workflow/status/Tochemey/gokv/build.yml)]((https://github.com/Tochemey/gokv/actions/workflows/build.yml))
+
+Simple Distributed in-memory key/value store. GoKV provides high availability and fault tolerance which makes it suitable large-scale applications system without sacrificing performance and reliability. 
+With GoKV, you can instantly create a fast, scalable, distributed system  across a cluster of computers.
+
+
+## Installation
+
+```bash
+go get github.com/tochemey/gokv
+```
+
+## Features
+
+- Robust APIs to manipulate key/value pairs. See: [APIs](#apis)
+- Discovery API to implement custom nodes discovery provider. See: [Discovery API](./discovery/provider.go)
+- Comes bundled with some discovery providers that can help you hit the ground running:
+    - Kubernetes provider [Soon]
+    - [NATS](https://nats.io/) [integration](./discovery/nats) is fully functional
+    - [Static](./discovery/static) is fully functional and for demo purpose
+    - [DNS](./discovery/dnssd) is fully functional
+
+## APIs
+
+- `Put`: create key/value pair that is eventually distributed in the cluster of nodes. The `key` is a string and the `value` is a byte array.
+- `Get`: retrieves the value of a given `key` from the cluster of nodes.
+- `Delete`: delete a given `key` from the cluster. At the moment the `key` is marked to be `deleted`.
+- `Exists`: check the existence of a given `key` in the cluster.
+
+## Discovery Providers
+
+### NATS Discovery Provider Setup
+
+To use the NATS discovery provider one needs to provide the following:
+
+- `Server`: the NATS Server address
+- `Subject`: the NATS subject to use
+- `Timeout`: the nodes discovery timeout
+- `MaxJoinAttempts`: the maximum number of attempts to connect an existing NATs server. Defaults to `5`
+- `ReconnectWait`: the time to backoff after attempting a reconnect to a server that we were already connected to previously. Default to `2 seconds`
+- `DiscoveryPort`: the discovery port of the running node
+- `Host`: the host address of the running node
+
+#### DNS Provider Setup
+
+This provider performs nodes discovery based upon the domain name provided. This is very useful when doing local development
+using docker.
+
+To use the DNS discovery provider one needs to provide the following:
+
+- `DomainName`: the domain name
+- `IPv6`: it states whether to lookup for IPv6 addresses.
+
+#### Static Provider Setup
+
+This provider performs nodes discovery based upon the list of static hosts addresses.
+The address of each host is the form of `host:port` where `port` is the discovery port.

internal/cluster/config.go → cluster/config.go

@@ -78,8 +78,8 @@ func (config *Config) WithDiscoveryProvider(provider discovery.Provider) *Config
 }
 
 // WithDiscoveryPort sets the discovery port
-func (config *Config) WithDiscoveryPort(gossipPort uint16) *Config {
-	config.discoveryPort = gossipPort
+func (config *Config) WithDiscoveryPort(port uint16) *Config {
+	config.discoveryPort = port
 	return config
 }
 

internal/cluster/node_test.go → cluster/node_test.go

@@ -33,9 +33,9 @@ import (
 	natsserver "github.com/nats-io/nats-server/v2/server"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
-	"github.com/tochemey/goakt/v2/discovery"
 	"github.com/travisjeffery/go-dynaport"
 
+	"github.com/tochemey/gokv/discovery"
 	"github.com/tochemey/gokv/discovery/nats"
 	"github.com/tochemey/gokv/internal/lib"
 	"github.com/tochemey/gokv/log"

discovery/dnssd/config.go

@@ -0,0 +1,43 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2022-2024 Tochemey
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package dnssd
+
+import "github.com/tochemey/gokv/internal/validation"
+
+// Config defines the discovery configuration
+type Config struct {
+	// Domain specifies the dns name
+	DomainName string
+	// IPv6 states whether to fetch ipv6 address instead of ipv4
+	// if it is false then all addresses are extracted
+	IPv6 *bool
+}
+
+// Validate checks whether the given discovery configuration is valid
+func (x Config) Validate() error {
+	return validation.New(validation.FailFast()).
+		AddValidator(validation.NewEmptyStringValidator("Namespace", x.DomainName)).
+		Validate()
+}

discovery/dnssd/config_test.go

@@ -0,0 +1,46 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2022-2024 Tochemey
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package dnssd
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestConfig(t *testing.T) {
+	t.Run("With valid configuration", func(t *testing.T) {
+		config := &Config{
+			DomainName: "google.com",
+		}
+		assert.NoError(t, config.Validate())
+	})
+	t.Run("With invalid configuration", func(t *testing.T) {
+		config := &Config{
+			DomainName: "",
+		}
+		assert.Error(t, config.Validate())
+	})
+}

discovery/dnssd/discovery.go

@@ -0,0 +1,158 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2022-2024 Tochemey
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package dnssd
+
+import (
+	"context"
+	"net"
+	"sync"
+
+	goset "github.com/deckarep/golang-set/v2"
+	"go.uber.org/atomic"
+
+	"github.com/tochemey/gokv/discovery"
+)
+
+const (
+	DomainName = "domain-name"
+	IPv6       = "ipv6"
+)
+
+// Discovery represents the DNS service discovery
+// IP addresses are looked up by querying the default
+// DNS resolver for A and AAAA records associated with the DNS name.
+type Discovery struct {
+	mu     sync.Mutex
+	config *Config
+
+	// states whether the actor system has started or not
+	initialized *atomic.Bool
+}
+
+// enforce compilation error
+var _ discovery.Provider = &Discovery{}
+
+// NewDiscovery returns an instance of the DNS discovery provider
+func NewDiscovery(config *Config) *Discovery {
+	return &Discovery{
+		mu:          sync.Mutex{},
+		config:      config,
+		initialized: atomic.NewBool(false),
+	}
+}
+
+// ID returns the discovery provider id
+func (d *Discovery) ID() string {
+	return "dns-sd"
+}
+
+// Initialize initializes the plugin: registers some internal data structures, clients etc.
+func (d *Discovery) Initialize() error {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	if d.initialized.Load() {
+		return discovery.ErrAlreadyInitialized
+	}
+
+	return d.config.Validate()
+}
+
+// Register registers this node to a service discovery directory.
+func (d *Discovery) Register() error {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+
+	if d.initialized.Load() {
+		return discovery.ErrAlreadyRegistered
+	}
+
+	d.initialized = atomic.NewBool(true)
+	return nil
+}
+
+// Deregister removes this node from a service discovery directory.
+func (d *Discovery) Deregister() error {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+
+	if !d.initialized.Load() {
+		return discovery.ErrNotInitialized
+	}
+	d.initialized = atomic.NewBool(false)
+	return nil
+}
+
+// DiscoverPeers returns a list of known nodes.
+func (d *Discovery) DiscoverPeers() ([]string, error) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+
+	if !d.initialized.Load() {
+		return nil, discovery.ErrNotInitialized
+	}
+
+	ctx := context.Background()
+
+	// set ipv6 filter
+	v6 := false
+	if d.config.IPv6 != nil {
+		v6 = *d.config.IPv6
+	}
+
+	var err error
+
+	// only extract ipv6
+	if v6 {
+		ips, err := net.DefaultResolver.LookupIP(ctx, "ip6", d.config.DomainName)
+		if err != nil {
+			return nil, err
+		}
+
+		ipList := make([]string, len(ips))
+		for index, ip := range ips {
+			ipList[index] = ip.String()
+		}
+
+		return goset.NewSet[string](ipList...).ToSlice(), nil
+	}
+
+	// lookup the addresses based upon the dns name
+	addrs, err := net.DefaultResolver.LookupIPAddr(ctx, d.config.DomainName)
+	if err != nil {
+		return nil, err
+	}
+
+	ipList := make([]string, len(addrs))
+	for index, addr := range addrs {
+		ipList[index] = addr.IP.String()
+	}
+
+	return goset.NewSet[string](ipList...).ToSlice(), nil
+}
+
+// Close closes the provider
+func (d *Discovery) Close() error {
+	return nil
+}