fix: simplify queueing code

lib/plugins/common/json-rpc.js

@@ -4,6 +4,7 @@ const uuid = require('uuid')
 const fs = require('fs')
 const _ = require('lodash/fp')
 const request = require('request-promise')
+const Queue = require('queue-promise')
 const { utils: coinUtils } = require('@lamassu/coins')
 
 const options = require('../../options')
@@ -49,40 +50,23 @@ function fetch (account = {}, method, params) {
     })
 }
 
-var fetchDigestRequestQueue = []
-var fetchDigestResponses = {}
+const DIGEST_QUEUE = new Queue({
+  concurrent: 1,
+  interval: 100,
+  start: false
+})
 
 function createDigestRequest (account = {}, method, params = []) {
-  const requestId = uuid.v4()
-
-  fetchDigestRequestQueue.push({
-    requestId,
-    options: generateDigestOptions(account, method, params, requestId),
-    status: 'sendPending'
-  })
-  fetchDigestResponses[requestId] = { status: 'receivePending' }
-
-  return new Promise((resolve, reject) => {
-    setTimeout(() => {
-      const request = _.find(it => it.requestId === requestId, fetchDigestRequestQueue)
-      const response = fetchDigestResponses[requestId]
-
-      if (_.isNil(response) || request.status === 'sendError') {
-        fetchDigestResponses[requestId].status = 'receiveError'
-        return reject()
-      }
-      fetchDigestResponses[requestId].status = 'finished'
-      return resolve(response)
-    }, 750)
-  })
+  DIGEST_QUEUE.enqueue(() => fetchDigest(account, method, params))
+  return DIGEST_QUEUE.dequeue()
 }
 
-function generateDigestOptions (account = {}, method, params, requestId) {
+function generateDigestOptions (account = {}, method, params) {
   const headers = {
     'Content-Type': 'application/json'
   }
 
-  const dataString = `{"jsonrpc":"2.0","id":"${requestId}","method":"${method}","params":${JSON.stringify(params)}}`
+  const dataString = `{"jsonrpc":"2.0","id":"${uuid.v4()}","method":"${method}","params":${JSON.stringify(params)}}`
 
   const options = {
     url: `http://localhost:${account.port}/json_rpc`,
@@ -100,88 +84,13 @@ function generateDigestOptions (account = {}, method, params, requestId) {
   return options
 }
 
-function executeRequestQueue (queue) {
-  return _.reduce(
-    (acc, value) => acc.then(a => {
-      const originalReq = _.find(it => it.requestId === value.requestId, queue)
-      switch (originalReq.status) {
-        case 'sendPending':
-          return request(value.options)
-            .then(res => {
-              originalReq.status = 'sendComplete'
-              return Promise.resolve(
-                _.merge(a, { [value.requestId]: { status: 'receiveComplete', ...JSON.parse(res).result } })
-              )
-            })
-            .catch(err => {
-              originalReq.status = 'sendError'
-              throw err
-            })
-        case 'sendComplete':
-          return Promise.resolve({ ...a })
-        case 'sendError':
-          return Promise.resolve({ ...a })
-        default:
-          break
-      }
-    }),
-    Promise.resolve(fetchDigestResponses),
-    queue
-  ).then(r => {
-    fetchDigestResponses = r
-    return fetchDigestResponses
-  })
-}
-
-function trimReqRes () {
-  const requestIds = _.keys(fetchDigestResponses)
-  _.forEach(it => {
-    const request = _.find(ite => ite.requestId === it, fetchDigestRequestQueue)
-    const response = fetchDigestResponses[it]
-
-    if (request && response && response.status === 'finished' && request.status === 'sendComplete') {
-      fetchDigestRequestQueue = _.filter(ite => ite.requestId !== it, fetchDigestRequestQueue)
-      delete fetchDigestResponses[it]
-    }
-  }, requestIds)
-}
-
-setInterval(
-  () => {
-    if (_.size(fetchDigestRequestQueue) === 0 && _.size(_.keys(fetchDigestResponses)) === 0) {
-      return
-    }
-    trimReqRes()
-    return executeRequestQueue(fetchDigestRequestQueue)
-  },
-  500
-)
-
 function fetchDigest(account = {}, method, params = []) {
   return Promise.resolve(true)
     .then(() => {
       if (_.isNil(account.port))
         throw new Error('port attribute required for jsonRpc')
 
-      const headers = {
-        'Content-Type': 'application/json'
-      }
-
-      const dataString = `{"jsonrpc":"2.0","id":"${uuid.v4()}","method":"${method}","params":${JSON.stringify(params)}}`
-
-      const options = {
-        url: `http://localhost:${account.port}/json_rpc`,
-        method: 'POST',
-        headers,
-        body: dataString,
-        forever: true,
-        auth: {
-          user: account.username,
-          pass: account.password,
-          sendImmediately: false
-        }
-      }
-
+      const options = generateDigestOptions(account, method, params)
       return request(options)
     })
     .then((res) => {