About

This is a final project developed to attent the last requirement of master degree class IN1118 (Distribution Platform) at CIn/UFPE. It consists of a RPC based middleware that contains of a Naming Service, Remote Service and a Client Proxy. These three parts compose the solution that were written in Go language applying the principles of Remoting Patterns.

Table of contents

[[TOC]]

How To

Installation

$ go get github.com/marlom-jobsom/gorpc

Implementations

1. Implement a struct that has a method
2. Create its Client Proxy
3. Instantiate and run a new Naming Service
4. Instantiate a new Remote Remote Service, register in it a instance of the structure created before, then run.
5. Use the Client Proxy created to call the method.

Follows more details for each steps:

Client Proxy

Below we have the NLG that contains the method TextTokenize, which will be running in the Remote Service.

// file: ./nlg/nlg.go
package nlg

import (
    "strings"
)

// Names used to register this struct on remote service
const (
    Name         = "NLG"
    TextTokenize = "TextTokenize"
)

// NewNLG builds a new instance of NLG
func NewNLG() *NLG {
    return &NLG{}
}

// NLG handles operations for text over RPC calls
type NLG struct{}

// TextTokenize tokenizes a text
func (n *NLG) TextTokenize(content string) []string {
    var tokens []string
    mapTokens := make(map[string]struct{})
    words := strings.Split(content, " ")

    for _, word := range words {
        mapTokens[word] = struct{}{}
    }

    for key := range mapTokens {
        tokens = append(tokens, key)
    }

    return tokens
}

Here we have its Client Proxy:

// file: ./nlg/nlg_proxy.go
package nlg

import (
    "github.com/marlom-jobsom/gorpc/internal/network/response"
    "github.com/marlom-jobsom/gorpc/pkg"
)

// NewClient build new instance of Client
func NewClient(lookupServerAddress string, encryptKey string) *Client {
    return &Client{
        proxy:              pkg.NewClientProxy(lookupServerAddress, encryptKey, Name),
        methodTextTokenize: TextTokenize,
    }
}

// Client is the bridge to NLG remote instance
type Client struct {
    proxy              *pkg.ClientProxy
    methodTextTokenize string
}

// TextTokenize tokenizes a text
func (n *Client) TextTokenize(text string) response.Response {
    // The implementation could treat the return to match with the original method.
    // For purpose of simplification, it's just returning it
    return n.proxy.Invoke(n.methodTextTokenize, text)
}

Finally, the main for the client:

// file: ./cmd/client/client.go
package main

import (
    "github.com/marlom-jobsom/gorpc/nlg"
    "github.com/marlom-jobsom/gorpc/pkg"
    "log"
)

func main() {
    lookupServerAddress, encryptKey := pkg.GetClientArgs()
    nlgClient := nlg.NewClient(lookupServerAddress, encryptKey)
    log.Println(nlgClient.TextTokenize("Silence is is golden"))
}

Remote Service

The main for Remote Service:

// file: ./cmd/remote_service/client.go
package main

import (
    "github.com/marlom-jobsom/gorpc/nlg"
    "github.com/marlom-jobsom/gorpc/pkg"
)

func main() {
    port, registrationServerAddress, encryptKey := pkg.GetRemoteServiceArgs()
    remoteServiceServer := pkg.NewRemoteServiceServer(port, registrationServerAddress, encryptKey)
    remoteServiceServer.RegisterServiceInNamingService(nlg.Name, nlg.NewNLG())
    remoteServiceServer.Run()
}

Naming Service

The main for Naming Service:

package main

import (
    "github.com/marlom-jobsom/gorpc/pkg"
)

func main() {
    lookupServerPort, registrationServerPort, encryptKey := pkg.GetNamingServiceArgs()
    namingServiceServer := pkg.NewNamingServiceServer(lookupServerPort, registrationServerPort, encryptKey)
    namingServiceServer.Run()
}

Running

Naming Service

It must be the first one to be started

# Help message
$ go run cmd/naming_service_server/main.go --help
Usage of main:
  -encrypt_key string
        The md5 encryptKey to encrypt/decrypt requests and responses (default "3a878ccc079a675df83041f1b695df6f")
  -lookup_server_port string
        The service look-up server port (default ":0")
  -registration_server_port string
        The service registration server port (default ":0")

# Running
$ go run cmd/naming_service_server/main.go
2018/11/27 08:47:04 Running remote service registration at "192.168.0.110:44729"
2018/11/27 08:47:04 Running remote service look-up at "192.168.0.110:44517"

Remote Service

It must be the second one to be started.

# Help message
$ go run cmd/remote_service_server/main.go --help
Usage of main:
  -encrypt_key string
        The md5 encryptKey to encrypt/decrypt requests and responses (default "3a878ccc079a675df83041f1b695df6f")
  -port string
        The port where the server will run. (e.g: :8000) (default ":0")
  -registration_server_address string
        The service registration server address

# Running
$ go run cmd/remote_service_server/main.go -registration_server_address "192.168.0.110:44729"
2018/11/27 08:49:22 Running remote service invoke at "192.168.0.110:33367"
2018/11/27 08:49:22 Registering remote services "[NLG]" from "192.168.0.110:33367"

Client Proxy

# Help message
$ go run cmd/client/main.go --help
Usage of main:
  -encrypt_key string
        The md5 encryptKey to encrypt/decrypt requests and responses (default "3a878ccc079a675df83041f1b695df6f")
  -lookup_server_address string
        The service look-up server address

# Running
$ go run cmd/client/main.go -lookup_server_address "192.168.0.110:44517"
2018/11/27 08:52:01 [Silence is golden] 378.311µs

Architecture

The pictures below presents the architectural vision of the project:

Client Proxy

Remote Service

Naming Service

Limitations (TODOs)

• It doesn't has a mechanism to generate and manage client keys for encrypt/decrypt requests;
• It still doesn't not support all basic Types in Golang;
• Missing Error handlers for following scenarios:
  • Nonexistence of a remote service
  • Nonexistence of a naming service
  • Wrong parameters given for a client invoke request
  • While marshal/unmarshal data
  • While writing data in the socket/request
• Missing unit tests