Making chaining of automations through different row creation/deletions possible.

packages/server/src/automations/steps/createRow.js

@@ -58,7 +58,7 @@ module.exports.definition = {
   },
 }
 
-module.exports.run = async function({ inputs, appId, apiKey }) {
+module.exports.run = async function({ inputs, appId, apiKey, emitter }) {
   // TODO: better logging of when actions are missed due to missing parameters
   if (inputs.row == null || inputs.row.tableId == null) {
     return
@@ -77,6 +77,7 @@ module.exports.run = async function({ inputs, appId, apiKey }) {
       body: inputs.row,
     },
     user: { appId },
+    eventEmitter: emitter,
   }
 
   try {

packages/server/src/automations/steps/createUser.js

@@ -58,7 +58,7 @@ module.exports.definition = {
   },
 }
 
-module.exports.run = async function({ inputs, appId, apiKey }) {
+module.exports.run = async function({ inputs, appId, apiKey, emitter }) {
   const { username, password, accessLevelId } = inputs
   const ctx = {
     user: {
@@ -67,6 +67,7 @@ module.exports.run = async function({ inputs, appId, apiKey }) {
     request: {
       body: { username, password, accessLevelId },
     },
+    eventEmitter: emitter,
   }
 
   try {

packages/server/src/automations/steps/deleteRow.js

@@ -50,7 +50,7 @@ module.exports.definition = {
   },
 }
 
-module.exports.run = async function({ inputs, appId, apiKey }) {
+module.exports.run = async function({ inputs, appId, apiKey, emitter }) {
   // TODO: better logging of when actions are missed due to missing parameters
   if (inputs.id == null || inputs.revision == null) {
     return
@@ -62,6 +62,7 @@ module.exports.run = async function({ inputs, appId, apiKey }) {
       revId: inputs.revision,
     },
     user: { appId },
+    eventEmitter: emitter,
   }
 
   try {

packages/server/src/automations/steps/updateRow.js

@@ -53,7 +53,7 @@ module.exports.definition = {
   },
 }
 
-module.exports.run = async function({ inputs, appId }) {
+module.exports.run = async function({ inputs, appId, emitter }) {
   if (inputs.rowId == null || inputs.row == null) {
     return
   }
@@ -79,6 +79,7 @@ module.exports.run = async function({ inputs, appId }) {
       body: inputs.row,
     },
     user: { appId },
+    eventEmitter: emitter,
   }
 
   try {

packages/server/src/automations/thread.js

@@ -2,6 +2,7 @@ const handlebars = require("handlebars")
 const actions = require("./actions")
 const logic = require("./logic")
 const automationUtils = require("./automationUtils")
+const AutomationEmitter = require("../events/AutomationEmitter")
 
 handlebars.registerHelper("object", value => {
   return new handlebars.SafeString(JSON.stringify(value))
@@ -32,12 +33,18 @@ function recurseMustache(inputs, context) {
  */
 class Orchestrator {
   constructor(automation, triggerOutput) {
+    this._metadata = triggerOutput.metadata
+    this._chainCount = this._metadata ? this._metadata.automationChainCount : 0
     this._appId = triggerOutput.appId
     // remove from context
     delete triggerOutput.appId
+    delete triggerOutput.metadata
     // step zero is never used as the mustache is zero indexed for customer facing
     this._context = { steps: [{}], trigger: triggerOutput }
     this._automation = automation
+    // create an emitter which has the chain count for this automation run in it, so it can block
+    // excessive chaining if required
+    this._emitter = new AutomationEmitter(this._chainCount + 1)
   }
 
   async getStepFunctionality(type, stepId) {
@@ -68,6 +75,7 @@ class Orchestrator {
           inputs: step.inputs,
           appId: this._appId,
           apiKey: automation.apiKey,
+          emitter: this._emitter,
         })
         if (step.stepId === FILTER_STEP_ID && !outputs.success) {
           break

packages/server/src/events/AutomationEmitter.js

@@ -0,0 +1,51 @@
+const { rowEmission, tableEmission } = require("./utils")
+const mainEmitter = require("./index")
+
+// max number of automations that can chain on top of each other
+const MAX_AUTOMATION_CHAIN = 5
+
+/**
+ * Special emitter which takes the count of automation runs which have occurred and blocks an
+ * automation from running if it has reached the maximum number of chained automations runs.
+ * This essentially "fakes" the normal emitter to add some functionality in-between to stop automations
+ * from getting stuck endlessly chaining.
+ */
+class AutomationEmitter {
+  constructor(chainCount) {
+    this.chainCount = chainCount
+    this.metadata = {
+      automationChainCount: chainCount,
+    }
+  }
+
+  emitRow(eventName, appId, row, table = null) {
+    // don't emit even if we've reached max automation chain
+    if (this.chainCount > MAX_AUTOMATION_CHAIN) {
+      return
+    }
+    rowEmission({
+      emitter: mainEmitter,
+      eventName,
+      appId,
+      row,
+      table,
+      metadata: this.metadata,
+    })
+  }
+
+  emitTable(eventName, appId, table = null) {
+    // don't emit even if we've reached max automation chain
+    if (this.chainCount > MAX_AUTOMATION_CHAIN) {
+      return
+    }
+    tableEmission({
+      emitter: mainEmitter,
+      eventName,
+      appId,
+      table,
+      metadata: this.metadata,
+    })
+  }
+}
+
+module.exports = AutomationEmitter

packages/server/src/events/index.js

@@ -1,4 +1,5 @@
 const EventEmitter = require("events").EventEmitter
+const { rowEmission, tableEmission } = require("./utils")
 
 /**
  * keeping event emitter in one central location as it might be used for things other than
@@ -12,36 +13,11 @@ const EventEmitter = require("events").EventEmitter
  */
 class BudibaseEmitter extends EventEmitter {
   emitRow(eventName, appId, row, table = null) {
-    let event = {
-      row,
-      appId,
-      tableId: row.tableId,
-    }
-    if (table) {
-      event.table = table
-    }
-    event.id = row._id
-    if (row._rev) {
-      event.revision = row._rev
-    }
-    this.emit(eventName, event)
+    rowEmission({ emitter: this, eventName, appId, row, table })
   }
 
   emitTable(eventName, appId, table = null) {
-    const tableId = table._id
-    let event = {
-      table: {
-        ...table,
-        tableId: tableId,
-      },
-      appId,
-      tableId: tableId,
-    }
-    event.id = tableId
-    if (table._rev) {
-      event.revision = table._rev
-    }
-    this.emit(eventName, event)
+    tableEmission({ emitter: this, eventName, appId, table })
   }
 }
 

packages/server/src/events/utils.js

@@ -0,0 +1,38 @@
+exports.rowEmission = ({ emitter, eventName, appId, row, table, metadata }) => {
+  let event = {
+    row,
+    appId,
+    tableId: row.tableId,
+  }
+  if (table) {
+    event.table = table
+  }
+  event.id = row._id
+  if (row._rev) {
+    event.revision = row._rev
+  }
+  if (metadata) {
+    event.metadata = metadata
+  }
+  emitter.emit(eventName, event)
+}
+
+exports.tableEmission = ({ emitter, eventName, appId, table, metadata }) => {
+  const tableId = table._id
+  let event = {
+    table: {
+      ...table,
+      tableId: tableId,
+    },
+    appId,
+    tableId: tableId,
+  }
+  event.id = tableId
+  if (table._rev) {
+    event.revision = table._rev
+  }
+  if (metadata) {
+    event.metadata = metadata
+  }
+  emitter.emit(eventName, event)
+}