refactor cash-in and cash-out

lib/cash-in/cash-in-atomic.js

@@ -0,0 +1,83 @@
+const _ = require('lodash/fp')
+const pgp = require('pg-promise')()
+
+const E = require('../error')
+
+const cashInLow = require('./cash-in-low')
+
+module.exports = {atomic}
+
+function atomic (machineTx, pi) {
+  const TransactionMode = pgp.txMode.TransactionMode
+  const isolationLevel = pgp.txMode.isolationLevel
+  const tmSRD = new TransactionMode({tiLevel: isolationLevel.serializable})
+
+  function transaction (t) {
+    const sql = 'select * from cash_in_txs where id=$1'
+    const sql2 = 'select * from bills where cash_in_txs_id=$1'
+
+    return t.oneOrNone(sql, [machineTx.id])
+    .then(row => {
+      if (row && row.tx_version >= machineTx.txVersion) throw new E.StaleTxError('Stale tx')
+
+      return t.any(sql2, [machineTx.id])
+      .then(billRows => {
+        const dbTx = cashInLow.toObj(row)
+
+        return preProcess(dbTx, machineTx, pi)
+        .then(preProcessedTx => cashInLow.upsert(t, dbTx, preProcessedTx))
+        .then(r => {
+          return insertNewBills(t, billRows, machineTx)
+          .then(newBills => _.set('newBills', newBills, r))
+        })
+      })
+    })
+  }
+
+  transaction.txMode = tmSRD
+
+  return transaction
+}
+
+function insertNewBills (t, billRows, machineTx) {
+  const bills = pullNewBills(billRows, machineTx)
+  if (_.isEmpty(bills)) return Promise.resolve([])
+
+  const dbBills = _.map(cashInLow.massage, bills)
+  const columns = _.keys(dbBills[0])
+  const sql = pgp.helpers.insert(dbBills, columns, 'bills')
+
+  return t.none(sql)
+  .then(() => bills)
+}
+
+function pullNewBills (billRows, machineTx) {
+  if (_.isEmpty(machineTx.bills)) return []
+
+  const toBill = _.mapKeys(_.camelCase)
+  const bills = _.map(toBill, billRows)
+
+  return _.differenceBy(_.get('id'), machineTx.bills, bills)
+}
+
+function preProcess (dbTx, machineTx, pi) {
+  // Note: The way this works is if we're clear to send,
+  // we mark the transaction as sendPending.
+  //
+  // If another process is trying to also mark this as sendPending
+  // that means that it saw the tx as sendPending=false.
+  // But if that's true, then it must be serialized before this
+  // (otherwise it would see sendPending=true), and therefore we can't
+  // be seeing sendPending=false (a pre-condition of clearToSend()).
+  // Therefore, one of the conflicting transactions will error,
+  // which is what we want.
+  return new Promise(resolve => {
+    if (!dbTx) return resolve(machineTx)
+
+    if (cashInLow.isClearToSend(dbTx, machineTx)) {
+      return resolve(_.set('sendPending', true, machineTx))
+    }
+
+    return resolve(machineTx)
+  })
+}