add SSL, config dirs, and Echo http server

.gitignore

@@ -14,4 +14,6 @@
 # Dependency directories (remove the comment below to include it)
 # vendor/
 
-.idea/
+.idea/
+
+cmd/go-jsonrpc-proxy

Makefile

@@ -0,0 +1,32 @@
+ORG_NAME := AxLabs
+REPO_NAME := go-jsonrpc-proxy
+PKG_ROOT := github.com/${ORG_NAME}/$(REPO_NAME)
+PKG_LIST := go list ${PKG_ROOT}/...
+PKG_GO_JSONRPC_PROXY := ${PKG_ROOT}/cmd
+CMD_DIR := ./cmd
+
+.PHONY: all lint vet test go-jsonrpc-proxy
+
+.EXPORT_ALL_VARIABLES:
+
+GO111MODULE=on
+
+all: lint vet test go-jsonrpc-proxy
+
+vet:
+	@go vet $(shell $(PKG_LIST))
+
+# Lint the files
+lint:
+	@golint -set_exit_status $(shell $(PKG_LIST))
+
+# Run unit tests
+test:
+	@go test -v -short -count=1 $(shell $(PKG_LIST))
+
+go-jsonrpc-proxy: $(CMD_DIR)/go-jsonrpc-proxy
+
+$(CMD_DIR)/go-jsonrpc-proxy:
+	@echo "Building $@..."
+	@go build -i -o $(CMD_DIR)/go-jsonrpc-proxy -v $(PKG_GO_JSONRPC_PROXY)
+	@chmod u+x $(CMD_DIR)/go-jsonrpc-proxy

README.md

@@ -1,6 +1,8 @@
-# go-jsonrpc-proxy
+> Simple JSON-RPC proxy based on RPC methods.
 
-Simple JSON-RPC proxy based on RPC methods.
+## How to Run
+
+TBD.
 
 ## Use Case
 
@@ -24,11 +26,15 @@ That's exactly what `go-jsonrpc-proxy` solves. :smiley:
 
 ## ToDos
 
+- [x] SSL support
+- [ ] Command line to support `--config=`
 - [ ] Rate limits for each declared method (using Redis)
 - [ ] Rate limits based on API keys (e.g., API key `X` 
 specified in the `Authorization` HTTP header can perform more 
 requests than API key `Y`)
 - [ ] More load balancer strategies. Nowadays forwarding hosts 
 are randomly chosen. 
+- [ ] Admin API to add/remove nodes to serve specific JSON-RPC 
+methods (or method patterns)
 - [ ] `docker-compose` file
 - [ ] Integration tests

cmd/main.go

@@ -3,39 +3,92 @@ package main
 import (
 	"github.com/AxLabs/go-jsonrpc-proxy/config"
 	"github.com/AxLabs/go-jsonrpc-proxy/server"
+	"github.com/labstack/echo/v4"
+	"github.com/labstack/echo/v4/middleware"
+	"github.com/labstack/gommon/log"
+	"github.com/shibukawa/configdir"
+	"golang.org/x/crypto/acme/autocert"
 	"math/rand"
 	"net/http"
 	"os"
 	"time"
 )
 
 func main() {
+	// initialize random
 	initRand()
 
-	configFilePath := getEnv("JSONRPC_PROXY_CONFIG_FILE", "jsonrpc-proxy.json")
+	// load config
+	configFilePath := getEnvVar("JSONRPC_PROXY_CONFIG_FILE", "jsonrpc-proxy.json")
 	config := config.LoadConfigFile(configFilePath)
 	server.LoadMap(config)
 
-	http.HandleFunc(config.BaseURL, server.HandleRequestAndRedirect)
-	if err := http.ListenAndServe(getListenAddress(), nil); err != nil {
-		panic(err)
+	sslEnabled := getEnvVar("JSONRPC_PROXY_SSL", "off")
+	sslDomain := getEnvVar("JSONRPC_PROXY_SSL_DOMAIN", "")
+	httpRedirectToHTTPS := getEnvVar("JSONRPC_PROXY_REDIRECT_TO_HTTPS", "on")
+	configDir := getConfigDir()
+
+	e := echo.New()
+
+	if sslEnabled == "on" && httpRedirectToHTTPS == "on" {
+		e.Pre(middleware.HTTPSRedirect())
+	}
+
+	e.AutoTLSManager.Cache = autocert.DirCache(configDir)
+	e.Use(middleware.Recover())
+	e.Use(middleware.Logger())
+
+	e.POST("/", echo.WrapHandler(http.HandlerFunc(server.HandleRequestAndRedirect)))
+
+	if sslEnabled == "on" {
+		if len(sslDomain) == 0 {
+			e.Logger.Fatalf("You should specify the domain name for the SSL.")
+		}
+		e.AutoTLSManager.HostPolicy = autocert.HostWhitelist(sslDomain)
+		e.Logger.Fatal(e.StartAutoTLS(getListenAddress()))
+	} else {
+		e.Logger.Fatal(e.Start(getListenAddress()))
 	}
 }
 
-// Get env var or default
-func getEnv(key, fallback string) string {
-	if value, ok := os.LookupEnv(key); ok {
-		return value
+// getEnvVar get an environment variable value, or returns a fallback value
+func getEnvVar(key, fallback string) string {
+	value, _ := getEnvVarAndIfExists(key, fallback)
+	return value
+}
+
+// getEnvVarAndIfExists Retrieves an environment variable value, or returns a default (fallback) value
+// It also returns true or false if the env variable exists or not
+func getEnvVarAndIfExists(key, fallback string) (string, bool) {
+	value, exists := os.LookupEnv(key)
+	if len(value) == 0 {
+		return fallback, exists
 	}
-	return fallback
+	return value, exists
 }
 
-// Get the port to listen on
+// getListenAddress get the port to listen on
 func getListenAddress() string {
-	port := getEnv("PORT", "2000")
+	port := getEnvVar("PORT", "2000")
 	return ":" + port
 }
 
+// getConfigDir get the configuration dir
+func getConfigDir() string {
+	configDirs := configdir.New("axlabs", "go-jsonrpc-proxy")
+	folders := configDirs.QueryFolders(configdir.Local)
+	configPath, ok := getEnvVarAndIfExists("JSONRPC_PROXY_CONFIG_PATH", folders[0].Path)
+	if ok {
+		configDirs.LocalPath = configPath
+	}
+	folders = configDirs.QueryFolders(configdir.Local)
+	err := folders[0].MkdirAll()
+	if err != nil {
+		log.Panicf("Not possible to create folder %v: %v", folders[0].Path, err)
+	}
+	return folders[0].Path
+}
+
 func initRand() {
 	// initialize global pseudo random generator
 	rand.Seed(time.Now().Unix())

config/config.go

@@ -6,19 +6,25 @@ import (
 	"log"
 )
 
+// Config var with the configuration parsed from the .json file
 var Config Configuration
 
+// Configuration type representing the .json config file
 type Configuration struct {
-	BaseURL string          `json:"base-url"`
-	Methods []MethodsConfig `json:"methods"`
+	BaseURL   string          `json:"base-url"`
+	SSL       bool            `json:"ssl,omitempty"`
+	SSLDomain string          `json:"ssl-domain,omitempty"`
+	Methods   []MethodsConfig `json:"methods"`
 }
 
+// MethodsConfig type representing the config for each JSON-RPC method
 type MethodsConfig struct {
 	Name      string   `json:"name"`
 	ProxyTo   []string `json:"proxy-to"`
 	RateLimit int      `json:"rate-limit"`
 }
 
+// LoadConfigFile loads the config file into an instance of Configuration type
 func LoadConfigFile(filePath string) Configuration {
 	file, errReadFile := ioutil.ReadFile(filePath)
 	if errReadFile != nil {
@@ -27,11 +33,12 @@ func LoadConfigFile(filePath string) Configuration {
 	return LoadConfig(string(file))
 }
 
+// LoadConfig loads the content (as JSON) into an instance of Configuration type
 func LoadConfig(content string) Configuration {
 	config := Configuration{}
-	errJson := json.Unmarshal([]byte(content), &config)
-	if errJson != nil {
-		log.Panicf("Could not read json content: %v", errJson)
+	errJSON := json.Unmarshal([]byte(content), &config)
+	if errJSON != nil {
+		log.Panicf("Could not read json content: %v", errJSON)
 	}
 	return config
 }

go.mod

@@ -3,11 +3,15 @@ module github.com/AxLabs/go-jsonrpc-proxy
 go 1.13
 
 require (
-	github.com/caddyserver/caddy v1.0.5
-	github.com/mholt/certmagic v0.8.3
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/kr/pretty v0.1.0 // indirect
+	github.com/labstack/echo/v4 v4.1.16
+	github.com/labstack/gommon v0.3.0
 	github.com/patrickmn/go-cache v2.1.0+incompatible
+	github.com/shibukawa/configdir v0.0.0-20170330084843-e180dbdc8da0
 	github.com/stretchr/testify v1.4.0
 	github.com/teambition/jsonrpc-go v0.0.0-20170418060308-ff2654212329
-	golang.org/x/sync v0.0.0-20190423024810-112230192c58
+	golang.org/x/crypto v0.0.0-20200221231518-2aa609cf4a9d
+	gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 // indirect
 	gopkg.in/square/go-jose.v2 v2.3.1
 )