# "undefined is not a function" error when feeding my simulation with .json/.csv file **URL:** \ **Category:** Gatling (Open-Source)\ **Created:** [December 23, 2024, 8:08pm UTC](https://community.gatling.io/t/undefined-is-not-a-function-error-when-feeding-my-simulation-with-json-csv-file/9477 "2024-12-23T20:08:39Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Hanna](https://avatars.discourse-cdn.com/v4/letter/h/b3f665/32.png) [@Hanna](https://community.gatling.io/u/Hanna)\ **Post date:** [December 23, 2024, 8:08pm UTC](https://community.gatling.io/t/undefined-is-not-a-function-error-when-feeding-my-simulation-with-json-csv-file/9477/1 "2024-12-23T20:08:40Z")
**Gatling version** : 3.13.2 **Gatling flavor** : javascript **Gatling build tool** : maven gradle sbt bundle npm My simulation works perfectly when retrieves only one key-value pair from .json/.csv file. But once I want to retrieve random value from .json/.csv file and add feeder - I receive error “undefined is not a function”. My simulation with csv feeding: ```javascript import { simulation, scenario, pause, atOnceUsers, AllowList, DenyList, StringBody, jsonFeeder, feed, csv } from "@gatling.io/core"; import {http, status} from "@gatling.io/http"; const credsFeeder = csv("../resources/creds.csv").random(); const httpProtocol = http .baseUrl("https://qa.myproject.co") .inferHtmlResources() .userAgentHeader("Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"); const headers_0 = { "Content-Type": "application/json", "Prefer": "timezone=Europe/Bratislava", "sec-ch-ua": "Google Chrome\";v=\"131\", \"Chromium\";v=\"131\", \"Not_A Brand\";v=\"24", "sec-ch-ua-mobile": "?0", "sec-ch-ua-platform": "macOS" }; const scn = scenario("loginSF") .feed(credsFeeder) .exec( http("request_0") .post("/api/authentication/auth/sign_in") .headers(headers_0) .body( StringBody(`{ "login": "#{login}", "password": "#{password}" }`) ) .check(status().is(200)) // Check if the login is successful ); export default simulation((setUp) => { setUp(scn.injectOpen(atOnceUsers(10))).protocols(httpProtocol); }); ``` My creds.csv: ```csv login,password log1,pas1 log2,pas2 ``` My simulation with json feeding: ```javascript import { simulation, scenario, atOnceUsers, jsonFeeder } from "@gatling.io/core"; import { http, status } from "@gatling.io/http"; const httpProtocol = http .baseUrl("https://qa.myproject.co") .inferHtmlResources() .userAgentHeader("Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"); const headers_0 = { "Content-Type": "application/json", "Prefer": "timezone=Europe/Bratislava", "sec-ch-ua": "Google Chrome\";v=\"131\", \"Chromium\";v=\"131\", \"Not_A Brand\";v=\"24", "sec-ch-ua-mobile": "?0", "sec-ch-ua-platform": "macOS", }; const credsFeeder = jsonFeeder("../resources/creds.json").random(); const scn = scenario("loginSF") .feed(credsFeeder) .exec( http("request_0") .post("/api/authentication/auth/sign_in") .headers(headers_0) .body((session) => { // Dynamically retrieve the login and password from the session const login = session.get("login"); const password = session.get("password"); return JSON.stringify({ login: login, password: password }); }) .check(status().is(200)) ); export default simulation((setUp) => { setUp(scn.injectOpen(atOnceUsers(100))).protocols(httpProtocol); }); ``` My creds.json: ```auto [ { "login": "log1", "password": "pass1" }, { "login": "log1", "password": "pass1" } ] ``` Both options work fine when there is only one key-value pair in .csv file/.json file Full error log: ```auto Run crashed org.graalvm.polyglot.PolyglotException: TypeError: undefined is not a function at .:=>(bundle.js:2893) at .:program(bundle.js:1) at org.graalvm.polyglot.Context.eval(Context.java:402) at io.gatling.js.JsSimulationHelper.loadSimulation(JsSimulationHelper.java:64) at io.gatling.js.JsSimulation.(JsSimulation.java:38) at java.base/jdk.internal.reflect.DirectConstructorHandleAccessor.newInstance(DirectConstructorHandleAccessor.java:62) ... 9 common frames omitted Wrapped by: java.lang.reflect.InvocationTargetException: null at java.base/jdk.internal.reflect.DirectConstructorHandleAccessor.newInstance(DirectConstructorHandleAccessor.java:74) at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:501) at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:485) at io.gatling.app.SimulationClass$Java.params(SimulationClass.scala:47) at io.gatling.app.Runner.load(Runner.scala:73) at io.gatling.app.Runner.run(Runner.scala:58) at io.gatling.app.Gatling$.start(Gatling.scala:83) at io.gatling.app.Gatling$.fromArgs(Gatling.scala:46) at io.gatling.app.Gatling$.main(Gatling.scala:40) at io.gatling.app.Gatling.main(Gatling.scala) Exception in thread "main" java.lang.reflect.InvocationTargetException at java.base/jdk.internal.reflect.DirectConstructorHandleAccessor.newInstance(DirectConstructorHandleAccessor.java:74) at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:501) at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:485) at io.gatling.app.SimulationClass$Java.params(SimulationClass.scala:47) at io.gatling.app.Runner.load(Runner.scala:73) at io.gatling.app.Runner.run(Runner.scala:58) at io.gatling.app.Gatling$.start(Gatling.scala:83) at io.gatling.app.Gatling$.fromArgs(Gatling.scala:46) at io.gatling.app.Gatling$.main(Gatling.scala:40) at io.gatling.app.Gatling.main(Gatling.scala) Caused by: org.graalvm.polyglot.PolyglotException: TypeError: undefined is not a function at .:=>(bundle.js:2893) at .:program(bundle.js:1) at org.graalvm.polyglot.Context.eval(Context.java:402) at io.gatling.js.JsSimulationHelper.loadSimulation(JsSimulationHelper.java:64) at io.gatling.js.JsSimulation.(JsSimulation.java:38) at java.base/jdk.internal.reflect.DirectConstructorHandleAccessor.newInstance(DirectConstructorHandleAccessor.java:62) ... 9 more /Users/anna/Documents/gatling-js/javascript/node_modules/@gatling.io/cli/target/java.js:33 reject(Error("Gatling process finished with code " + code)); ^ Error: Gatling process finished with code 1 at ChildProcess. (/Users/anna/Documents/gatling-js/javascript/node_modules/@gatling.io/cli/target/java.js:33:24) at ChildProcess.emit (node:events:513:28) at maybeClose (node:internal/child_process:1101:16) at ChildProcess._handle.onexit (node:internal/child_process:305:5) ``` ---
**Author:** ![slandelle](https://dub1.discourse-cdn.com/flex013/user_avatar/community.gatling.io/slandelle/32/4_2.png) [@slandelle](https://community.gatling.io/u/slandelle)\ **Post date:** [December 23, 2024, 9:15pm UTC](https://community.gatling.io/t/undefined-is-not-a-function-error-when-feeding-my-simulation-with-json-csv-file/9477/2 "2024-12-23T21:15:23Z")
I’ve fixed an import error in your CSV sample. Then: - `jsonFeeder("../resources/creds.json")` is wrong. You must use paths contained in the `resources` folder, meaning directly `jsonFeeder("creds.json")` in this case. - the `qa.structuretest.co` can’t be resolved, I guess it’s an internal one. Please build a test that can be run by someone outside your organization, eg targeting `https://httpbin.org/`. ---
**Author:** ![Hanna](https://avatars.discourse-cdn.com/v4/letter/h/b3f665/32.png) [@Hanna](https://community.gatling.io/u/Hanna)\ **Post date:** [December 23, 2024, 9:23pm UTC](https://community.gatling.io/t/undefined-is-not-a-function-error-when-feeding-my-simulation-with-json-csv-file/9477/3 "2024-12-23T21:23:35Z")
Thanks, @slandelle. But it is not about path, initially I used exactly “creds.json” path, and rechecked now too - same error ---
**Author:** ![slandelle](https://dub1.discourse-cdn.com/flex013/user_avatar/community.gatling.io/slandelle/32/4_2.png) [@slandelle](https://community.gatling.io/u/slandelle)\ **Post date:** [December 23, 2024, 9:30pm UTC](https://community.gatling.io/t/undefined-is-not-a-function-error-when-feeding-my-simulation-with-json-csv-file/9477/4 "2024-12-23T21:30:06Z")
Please build a proper reproducer I can run on my side. I only bothered running your CSV sample with the import and path fixes and hitting `google.com` instead and it worked (100% 404 as expected, but Gatling was able to build the request bodies). ---
**Author:** ![Hanna](https://avatars.discourse-cdn.com/v4/letter/h/b3f665/32.png) [@Hanna](https://community.gatling.io/u/Hanna)\ **Post date:** [December 23, 2024, 9:41pm UTC](https://community.gatling.io/t/undefined-is-not-a-function-error-when-feeding-my-simulation-with-json-csv-file/9477/5 "2024-12-23T21:41:50Z")
strange, I’ve just changed baseUrl to “[https://google.com](https://google.com)” and still see same error, Gatling is not able to build the request bodies: ```javascript import { simulation, scenario, atOnceUsers, jsonFeeder } from "@gatling.io/core"; import { http, status } from "@gatling.io/http"; const httpProtocol = http .baseUrl("https://google.com") .inferHtmlResources() .userAgentHeader("Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"); const headers_0 = { "Content-Type": "application/json", "Prefer": "timezone=Europe/Bratislava", "sec-ch-ua": "Google Chrome\";v=\"131\", \"Chromium\";v=\"131\", \"Not_A Brand\";v=\"24", "sec-ch-ua-mobile": "?0", "sec-ch-ua-platform": "macOS", }; const credsFeeder = jsonFeeder("creds.json").random(); const scn = scenario("loginSF") .feed(credsFeeder) .exec( http("request_0") .post("/api/authentication/auth/sign_in") .headers(headers_0) .body((session) => { // Dynamically retrieve the login and password from the session const login = session.get("login"); const password = session.get("password"); return JSON.stringify({ login: login, password: password }); }) .check(status().is(200)) ); export default simulation((setUp) => { setUp(scn.injectOpen(atOnceUsers(100))).protocols(httpProtocol); }); ``` ![Screenshot 2024-12-23 at 22.51.27](https://europe1.discourse-cdn.com/flex013/uploads/gatling2/original/2X/a/a40b44eba2760555dd059b03dc8aea87254c39b0.jpeg) ---
**Author:** ![slandelle](https://dub1.discourse-cdn.com/flex013/user_avatar/community.gatling.io/slandelle/32/4_2.png) [@slandelle](https://community.gatling.io/u/slandelle)\ **Post date:** [December 23, 2024, 10:05pm UTC](https://community.gatling.io/t/undefined-is-not-a-function-error-when-feeding-my-simulation-with-json-csv-file/9477/6 "2024-12-23T22:05:08Z")
Your CSV sample was almost correct, except for the missing import and the path. Your JSON sample has way more errors: - you must pass a `StringBody` (or another “Body” type) to `body()` =\> `StringBody(your function)` - it’s not `jsonFeeder` but `jsonFile`, see [Gatling session scripting reference - feeders](https://docs.gatling.io/reference/script/core/session/feeders/#json-feeders) - missing imports for `StringBody, feed, jsonFile` I’m not a JavaScript developper, but I would expect all these errors to be better reported when using TypeScript. ---
**Author:** ![Hanna](https://avatars.discourse-cdn.com/v4/letter/h/b3f665/32.png) [@Hanna](https://community.gatling.io/u/Hanna)\ **Post date:** [December 24, 2024, 12:49pm UTC](https://community.gatling.io/t/undefined-is-not-a-function-error-when-feeding-my-simulation-with-json-csv-file/9477/7 "2024-12-24T12:49:17Z")
Thanks a lot @slandelle, it was perfect idea to use TypeScript. I modified just a bit my scripts and both scripts, using .json and .csv feeding, work perfectly. But when I run exactly the same 100% identical script with .csv feeding using JS, I still see this “undefined is not a function” error. So, apparently issue is not on my side in this case. So, it is just better to use TS, thanks! ---
**Author:** ![slandelle](https://dub1.discourse-cdn.com/flex013/user_avatar/community.gatling.io/slandelle/32/4_2.png) [@slandelle](https://community.gatling.io/u/slandelle)\ **Post date:** [December 24, 2024, 1:14pm UTC](https://community.gatling.io/t/undefined-is-not-a-function-error-when-feeding-my-simulation-with-json-csv-file/9477/8 "2024-12-24T13:14:01Z")
No, really, your script is buggy. Here’s the corrected version with the fixes I provided: ```javascript import { simulation, scenario, atOnceUsers, StringBody, feed, jsonFile } from "@gatling.io/core"; import { http, status } from "@gatling.io/http"; const credsFeeder = jsonFile("creds.json").random(); const httpProtocol = http .baseUrl("https://google.com") .inferHtmlResources() .userAgentHeader("Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"); const headers_0 = { "Content-Type": "application/json", "Prefer": "timezone=Europe/Bratislava", "sec-ch-ua": "Google Chrome\";v=\"131\", \"Chromium\";v=\"131\", \"Not_A Brand\";v=\"24", "sec-ch-ua-mobile": "?0", "sec-ch-ua-platform": "macOS", }; const scn = scenario("loginSF") .feed(credsFeeder) .exec( http("request_0") .post("/api/authentication/auth/sign_in") .headers(headers_0) .body( StringBody( (session) => { // Dynamically retrieve the login and password from the session const login = session.get("login"); const password = session.get("password"); return JSON.stringify({ login: login, password: password }); } ) ) .check(status().is(200)) ); export default simulation((setUp) => { setUp(scn.injectOpen(atOnceUsers(100))).protocols(httpProtocol); }); ``` ```auto ---- Global Information -------------------------------------------------------- > request count 100 (OK=0 KO=100 ) > min response time 171 (OK=- KO=171 ) > max response time 296 (OK=- KO=296 ) > mean response time 227 (OK=- KO=227 ) > std deviation 30 (OK=- KO=30 ) > response time 50th percentile 224 (OK=- KO=224 ) > response time 75th percentile 252 (OK=- KO=252 ) > response time 95th percentile 266 (OK=- KO=266 ) > response time 99th percentile 296 (OK=- KO=296 ) > mean requests/sec 100 (OK=- KO=100 ) ---- Response Time Distribution ------------------------------------------------ > t < 800 ms 0 ( 0%) > 800 ms <= t < 1200 ms 0 ( 0%) > t >= 1200 ms 0 ( 0%) > failed 100 ( 100%) ---- Errors -------------------------------------------------------------------- > status.find.is(200), but actually found 404 100 (100,0%) ================================================================================ ``` ---
**Author:** ![Hanna](https://avatars.discourse-cdn.com/v4/letter/h/b3f665/32.png) [@Hanna](https://community.gatling.io/u/Hanna)\ **Post date:** [December 24, 2024, 1:22pm UTC](https://community.gatling.io/t/undefined-is-not-a-function-error-when-feeding-my-simulation-with-json-csv-file/9477/9 "2024-12-24T13:22:54Z")
ok) but my version also works: ```auto import { simulation, scenario, csvFeeder, atOnceUsers, exec, csv, pause, css, feed, repeat, tryMax, rampUsers, StringBody, jsonFeeder, jsonFile } from "@gatling.io/core"; import { http, status } from "@gatling.io/http"; const httpProtocol = http .baseUrl("https://google.com") .inferHtmlResources() .userAgentHeader( "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36" ); const headers_0 = { "Content-Type": "application/json", "Prefer": "timezone=Europe/Bratislava", "sec-ch-ua": 'Google Chrome";v="131", "Chromium";v="131", "Not_A Brand";v="24', "sec-ch-ua-mobile": "?0", "sec-ch-ua-platform": "macOS", }; const credsFeeder = jsonFile("resources/creds.json").random(); const scn = scenario("RecordedSimulation") .feed(credsFeeder) .exec( http("request_0") .post("/api/authentication/auth/sign_in") .headers(headers_0) .body( StringBody('{"login": "#{login}", "password": "#{password}"}') ) .check(status().is(200)) ); export default simulation((setUp) => { setUp(scn.injectOpen(atOnceUsers(100))).protocols(httpProtocol); }); ================================================================================ ---- Global Information -------------------------------------------------------- > request count 100 (OK=100 KO=0 ) > min response time 2267 (OK=2267 KO=- ) > max response time 10143 (OK=10143 KO=- ) > mean response time 7872 (OK=7872 KO=- ) > std deviation 2001 (OK=2001 KO=- ) > response time 50th percentile 8438 (OK=8438 KO=- ) > response time 75th percentile 9653 (OK=9653 KO=- ) > response time 95th percentile 10003 (OK=10003 KO=- ) > response time 99th percentile 10143 (OK=10143 KO=- ) > mean requests/sec 9.09 (OK=9.09 KO=- ) ---- Response Time Distribution ------------------------------------------------ > t < 800 ms 0 ( 0%) > 800 ms <= t < 1200 ms 0 ( 0%) > t >= 1200 ms 100 ( 100%) > failed 0 ( 0%) ================================================================================ ``` ---
**Author:** ![system](https://europe1.discourse-cdn.com/flex013/uploads/gatling2/original/2X/b/b148e0742de35c6280726cabf3ecd3de2d320f63.png) [@system](https://community.gatling.io/u/system)\ **Post date:** [January 23, 2025, 1:23pm UTC](https://community.gatling.io/t/undefined-is-not-a-function-error-when-feeding-my-simulation-with-json-csv-file/9477/10 "2025-01-23T13:23:02Z")
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