Define rough architecture for middleware

The functionality of the middleware is now split into three packages. The
middleware package takes care of communicating with bitcoind and
lightningd and emits an event if new data is received.

The handlers package takes care of the communication with
the bitbox-wallet-app. It upgrades connections to websocket, if
requested, and starts the main middleware event loop. Events from the
middleware are caught and passed into a websocket handler.

The main package is what is compiled into a binary. It parses command
line arguments and creates new middleware and handler instances.
This commit also implements logging, where each package creates its own
logrus logging instance.

middleware/Makefile

@@ -12,6 +12,6 @@ envinit:
 	./scripts/go-get.sh v1.16.0 github.com/golangci/golangci-lint/cmd/golangci-lint
 	go get -u github.com/golang/dep/cmd/dep
 native: check-env
-	go build -o $(REPO_ROOT)/build/base-middleware ./src/
+	go build -o $(REPO_ROOT)/build/base-middleware ./cmd/middleware/
 aarch64: check-env
-	GOARCH=arm64 go build -o $(REPO_ROOT)/build/base-middleware ./src/
+	GOARCH=arm64 go build -o $(REPO_ROOT)/build/base-middleware ./cmd/middleware/

middleware/cmd/middleware/main.go

@@ -0,0 +1,39 @@
+// Package main provides the entry point into the middleware and accepts command line arguments.
+// Once compiled, the application pipes information from bitbox-base backend services to the bitbox-wallet-app and serves as an authenticator to the bitbox-base.
+package main
+
+import (
+	"flag"
+	"log"
+	"net/http"
+
+	middleware "github.com/digitalbitbox/bitbox-base/middleware/src"
+	"github.com/digitalbitbox/bitbox-base/middleware/src/handlers"
+)
+
+func main() {
+	bitcoinRPCUser := flag.String("rpcuser", "rpcuser", "Bitcoin rpc user name")
+	bitcoinRPCPassword := flag.String("rpcpassword", "rpcpassword", "Bitcoin rpc password")
+	bitcoinRPCPort := flag.String("rpcport", "8332", "Bitcoin rpc port, localhost is assumed as an address")
+	lightningRPCPath := flag.String("lightning-rpc-path", "/home/bitcoin/.lightning/lightning-rpc", "Path to the lightning rpc unix socket")
+	flag.Parse()
+
+	logBeforeExit := func() {
+		// Recover from all panics and log error before panicking again.
+		if r := recover(); r != nil {
+			// r is of type interface{}, just print its value
+			log.Printf("%v, error detected, shutting down.", r)
+			panic(r)
+		}
+	}
+	defer logBeforeExit()
+	middleware := middleware.NewMiddleware(*bitcoinRPCUser, *bitcoinRPCPassword, *bitcoinRPCPort, *lightningRPCPath)
+	log.Println("--------------- Started middleware --------------")
+
+	handlers := handlers.NewHandlers(middleware)
+	log.Println("Binding middleware api to port 8845")
+
+	if err := http.ListenAndServe(":8845", handlers.Router); err != nil {
+		log.Println(err.Error() + " Failed to listen for HTTP")
+	}
+}

middleware/src/handlers/handlers.go

@@ -0,0 +1,89 @@
+// Package handlers implements an api for the bitbox-wallet-app to talk to.
+package handlers
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+
+	middleware "github.com/digitalbitbox/bitbox-base/middleware/src"
+	"github.com/gorilla/mux"
+	"github.com/gorilla/websocket"
+)
+
+// Middleware provides an interface to the middleware package.
+type Middleware interface {
+	Start() <-chan *middleware.SampleInfo
+}
+
+// Handlers provides a web api
+type Handlers struct {
+	Router  *mux.Router
+	clients map[*websocket.Conn]bool
+	//upgrader takes an http request and upgrades the connection with its origin to websocket
+	upgrader   websocket.Upgrader
+	middleware Middleware
+	//TODO(TheCharlatan): In future this event should have a generic interface (thus only containing raw json)
+	middlewareEvents <-chan *middleware.SampleInfo
+}
+
+// NewHandlers returns a handler instance.
+func NewHandlers(middlewareInstance Middleware) *Handlers {
+	router := mux.NewRouter()
+
+	handlers := &Handlers{
+		middleware: middlewareInstance,
+		Router:     router,
+		clients:    make(map[*websocket.Conn]bool),
+		upgrader: websocket.Upgrader{
+			CheckOrigin: func(r *http.Request) bool {
+				return true
+			},
+		},
+	}
+	handlers.Router.HandleFunc("/", handlers.rootHandler).Methods("GET")
+	handlers.Router.HandleFunc("/ws", handlers.wsHandler)
+
+	handlers.middlewareEvents = handlers.middleware.Start()
+	go handlers.echo()
+	return handlers
+}
+
+// TODO(TheCharlatan): Define a better error-response system. In future, this should be the first step in an authentication procedure.
+// rootHandler provides an endpoint to indicate that the middleware is online and able to handle requests.
+func (handlers *Handlers) rootHandler(w http.ResponseWriter, r *http.Request) {
+	_, err := w.Write([]byte("OK!!\n"))
+	if err != nil {
+		log.Println(err.Error() + " Failed to write response bytes in root handler")
+	}
+}
+
+func (handlers *Handlers) wsHandler(w http.ResponseWriter, r *http.Request) {
+	ws, err := handlers.upgrader.Upgrade(w, r, nil)
+	if err != nil {
+		log.Println(err.Error() + " Failed to upgrade connection")
+	}
+
+	// register client
+	handlers.clients[ws] = true
+}
+
+func (handlers *Handlers) echo() {
+	var i = 0
+	for {
+		i++
+		val := <-handlers.middlewareEvents
+		blockinfo := fmt.Sprintf("%d %f %d %s", val.Blocks, val.Difficulty, i, val.LightningAlias)
+		// send to every client that is currently connected
+		//fmt.Println(blockinfo)
+		for client := range handlers.clients {
+			log.Println(blockinfo)
+			err := client.WriteMessage(websocket.TextMessage, []byte(blockinfo))
+			if err != nil {
+				log.Println(err.Error() + " Unexpected websocket error")
+				client.Close()
+				delete(handlers.clients, client)
+			}
+		}
+	}
+}

middleware/src/middleware.go

@@ -0,0 +1,105 @@
+// Package middleware emits events with data from services running on the base.
+package middleware
+
+import (
+	"log"
+	"time"
+
+	"github.com/btcsuite/btcd/rpcclient"
+	lightning "github.com/fiatjaf/lightningd-gjson-rpc"
+)
+
+// SampleInfo holds sample information from c-lightning and bitcoind. It is temporary for testing purposes.
+type SampleInfo struct {
+	Blocks         int64   `json:"blocks"`
+	Difficulty     float64 `json:"difficulty"`
+	LightningAlias string  `json:"lightning_alias"`
+}
+
+// Middleware connects to services on the base with provided parrameters and emits events for the handler.
+type Middleware struct {
+	info                                               SampleInfo
+	events                                             chan *SampleInfo
+	bitcoinRPCUser, bitcoinRPCPassword, bitcoinRPCPort string
+	lightningRPCPath                                   string
+}
+
+// NewMiddleware returns a new instance of the middleware
+func NewMiddleware(bitcoinRPCUser, bitcoinRPCPassword, bitcoinRPCPort, lightningRPCPath string) *Middleware {
+	middleware := &Middleware{
+		events:             make(chan *SampleInfo),
+		bitcoinRPCUser:     bitcoinRPCUser,
+		bitcoinRPCPassword: bitcoinRPCPassword,
+		bitcoinRPCPort:     bitcoinRPCPort,
+		lightningRPCPath:   lightningRPCPath,
+		info: SampleInfo{
+			Blocks:         0,
+			Difficulty:     0.0,
+			LightningAlias: "disconnected",
+		},
+	}
+
+	return middleware
+}
+
+// demoBitcoinRPC is a function that demonstrates a connection to bitcoind. Currently it gets the blockcount and difficulty and writes it into the SampleInfo.
+func (middleware *Middleware) demoBitcoinRPC(bitcoinRPCUser, bitcoinRPCPassword, bitcoinRPCPort string) {
+	connCfg := rpcclient.ConnConfig{
+		HTTPPostMode: true,
+		DisableTLS:   true,
+		Host:         "127.0.0.1:" + bitcoinRPCPort,
+		User:         bitcoinRPCUser,
+		Pass:         bitcoinRPCPassword,
+	}
+	client, err := rpcclient.New(&connCfg, nil)
+	if err != nil {
+		log.Println(err.Error() + " Failed to create new bitcoind rpc client")
+	}
+	//client is shutdown/deconstructed again as soon as this function returns
+	defer client.Shutdown()
+
+	//Get current block count.
+	var blockCount int64
+	blockCount, err = client.GetBlockCount()
+	if err != nil {
+		log.Println(err.Error() + " No blockcount received")
+	} else {
+		middleware.info.Blocks = blockCount
+	}
+	blockChainInfo, err := client.GetBlockChainInfo()
+	if err != nil {
+		log.Println(err.Error() + " GetBlockChainInfo rpc call failed")
+	} else {
+		middleware.info.Difficulty = blockChainInfo.Difficulty
+	}
+
+}
+
+// demoCLightningRPC demonstrates a connection with lightnind. Currently it gets the lightningd alias and writes it into the SampleInfo.
+func (middleware *Middleware) demoCLightningRPC(lightningRPCPath string) {
+	ln := &lightning.Client{
+		Path: lightningRPCPath,
+	}
+
+	nodeinfo, err := ln.Call("getinfo")
+	if err != nil {
+		log.Println(err.Error() + " Lightningd getinfo called failed.")
+	} else {
+		middleware.info.LightningAlias = nodeinfo.Get("alias").String()
+	}
+}
+
+func (middleware *Middleware) rpcLoop() {
+	for {
+		middleware.demoBitcoinRPC(middleware.bitcoinRPCUser, middleware.bitcoinRPCPassword, middleware.bitcoinRPCPort)
+		middleware.demoCLightningRPC(middleware.lightningRPCPath)
+		middleware.events <- &middleware.info
+		time.Sleep(5 * time.Second)
+	}
+}
+
+// Start gives a trigger for the handler to start the rpc event loop
+func (middleware *Middleware) Start() <-chan *SampleInfo {
+	go middleware.rpcLoop()
+	return middleware.events
+}