Use isolated-vm

packages/server/src/jsRunner/index.ts

@@ -1,68 +1,41 @@
-import vm from "vm"
 import env from "../environment"
-import { setJSRunner, setOnErrorLog } from "@budibase/string-templates"
-import { context, logging, timers } from "@budibase/backend-core"
+import { setJSRunner, JsErrorTimeout } from "@budibase/string-templates"
 import tracer from "dd-trace"
-import { serializeError } from "serialize-error"
 
-type TrackerFn = <T>(f: () => T) => T
+import { IsolatedVM } from "./vm"
+import { context } from "@budibase/backend-core"
 
 export function init() {
-  setJSRunner((js: string, ctx: vm.Context) => {
+  setJSRunner((js: string, ctx: Record<string, any>) => {
     return tracer.trace("runJS", {}, span => {
-      const perRequestLimit = env.JS_PER_REQUEST_TIMEOUT_MS
-      let track: TrackerFn = f => f()
-      if (perRequestLimit) {
-        const bbCtx = tracer.trace("runJS.getCurrentContext", {}, span =>
-          context.getCurrentContext()
-        )
-        if (bbCtx) {
-          if (!bbCtx.jsExecutionTracker) {
-            span?.addTags({
-              createdExecutionTracker: true,
-            })
-            bbCtx.jsExecutionTracker = tracer.trace(
-              "runJS.createExecutionTimeTracker",
-              {},
-              span => timers.ExecutionTimeTracker.withLimit(perRequestLimit)
-            )
-          }
-          span?.addTags({
-            js: {
-              limitMS: bbCtx.jsExecutionTracker.limitMs,
-              elapsedMS: bbCtx.jsExecutionTracker.elapsedMS,
-            },
-          })
-          // We call checkLimit() here to prevent paying the cost of creating
-          // a new VM context below when we don't need to.
-          tracer.trace("runJS.checkLimitAndBind", {}, span => {
-            bbCtx.jsExecutionTracker!.checkLimit()
-            track = bbCtx.jsExecutionTracker!.track.bind(
-              bbCtx.jsExecutionTracker
-            )
+      try {
+        const bbCtx = context.getCurrentContext()!
+
+        let { vm } = bbCtx
+        if (!vm) {
+          // Can't copy the native helpers into the isolate. We just ignore them as they are handled properly from the helpersSource
+          const { helpers, ...ctxToPass } = ctx
+
+          vm = new IsolatedVM({
+            memoryLimit: env.JS_RUNNER_MEMORY_LIMIT,
+            invocationTimeout: env.JS_PER_INVOCATION_TIMEOUT_MS,
+            isolateAccumulatedTimeout: env.JS_PER_REQUEST_TIMEOUT_MS,
           })
+            .withContext(ctxToPass)
+            .withHelpers()
+
+          bbCtx.vm = vm
         }
-      }
 
-      ctx = {
-        ...ctx,
-        alert: undefined,
-        setInterval: undefined,
-        setTimeout: undefined,
-      }
+        const result = vm.execute(js)
 
-      vm.createContext(ctx)
-      return track(() =>
-        vm.runInNewContext(js, ctx, {
-          timeout: env.JS_PER_INVOCATION_TIMEOUT_MS,
-        })
-      )
+        return result
+      } catch (error: any) {
+        if (error.message === "Script execution timed out.") {
+          throw new JsErrorTimeout()
+        }
+        throw error
+      }
     })
   })
-
-  if (env.LOG_JS_ERRORS) {
-    setOnErrorLog((error: Error) => {
-      logging.logWarn(JSON.stringify(serializeError(error)))
-    })
-  }
 }

packages/server/src/threads/query.ts

@@ -127,10 +127,16 @@ class QueryRunner {
 
     // transform as required
     if (transformer) {
-      const runner = new ScriptRunner(transformer, {
-        data: rows,
-        params: enrichedParameters,
-      })
+      const runner = new ScriptRunner(
+        transformer,
+        {
+          data: rows,
+          params: enrichedParameters,
+        },
+        {
+          parseBson: datasource.source === SourceName.MONGODB,
+        }
+      )
       rows = runner.execute()
     }
 

packages/server/src/utilities/scriptRunner.ts

@@ -1,28 +1,40 @@
-import fetch from "node-fetch"
-import { VM, VMScript } from "vm2"
+import tracer, { Span } from "dd-trace"
+import env from "../environment"
+import { IsolatedVM } from "../jsRunner/vm"
 
 const JS_TIMEOUT_MS = 1000
 
 class ScriptRunner {
-  vm: VM
-  results: { out: string }
-  script: VMScript
+  private code: string
+  private vm: IsolatedVM
 
-  constructor(script: string, context: any) {
-    const code = `let fn = () => {\n${script}\n}; results.out = fn();`
-    this.vm = new VM({
-      timeout: JS_TIMEOUT_MS,
-    })
-    this.results = { out: "" }
-    this.vm.setGlobals(context)
-    this.vm.setGlobal("fetch", fetch)
-    this.vm.setGlobal("results", this.results)
-    this.script = new VMScript(code)
+  private tracerSpan: Span
+
+  constructor(script: string, context: any, { parseBson = false } = {}) {
+    this.tracerSpan = tracer.startSpan("scriptRunner", { tags: { parseBson } })
+
+    this.code = `(() => {${script}})();`
+    this.vm = new IsolatedVM({
+      memoryLimit: env.JS_RUNNER_MEMORY_LIMIT,
+      invocationTimeout: JS_TIMEOUT_MS,
+    }).withContext(context)
+
+    if (parseBson && context.data) {
+      this.vm = this.vm.withParsingBson(context.data)
+    }
   }
 
   execute() {
-    this.vm.run(this.script)
-    return this.results.out
+    const result = tracer.trace(
+      "scriptRunner.execute",
+      { childOf: this.tracerSpan },
+      () => {
+        const result = this.vm.execute(this.code)
+        return result
+      }
+    )
+    this.tracerSpan.finish()
+    return result
   }
 }