Internal Error 500( Unable to read webpack stats file)

Stefan31 · July 15, 2020, 5:46pm

I just downloaded the Vaadin 14 starter project which uses Vaadin 14.3.0.
While mvn jetty:run works just fine mvn jetty:run-exploded -Dvaadin.productionMode produces a 500 error in the webbrowser:

javax.servlet.ServletException: javax.servlet.ServletException: com.vaadin.flow.server.ServiceException: com.vaadin.flow.server.BootstrapException: Unable to read webpack stats file.
	at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:146)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
	at org.eclipse.jetty.server.Server.handle(Server.java:502)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:370)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:267)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:305)
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103)
	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:117)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:765)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:683)
	at java.lang.Thread.run(Thread.java:748)
Caused by: javax.servlet.ServletException: com.vaadin.flow.server.ServiceException: com.vaadin.flow.server.BootstrapException: Unable to read webpack stats file.
	at com.vaadin.flow.server.VaadinServlet.service(VaadinServlet.java:249)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:873)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:542)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:548)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1701)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1345)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:480)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1668)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1247)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144)
	at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:220)
	at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:126)
	... 10 more
Caused by: com.vaadin.flow.server.ServiceException: com.vaadin.flow.server.BootstrapException: Unable to read webpack stats file.
	at com.vaadin.flow.server.VaadinService.handleExceptionDuringRequest(VaadinService.java:1594)
	at com.vaadin.flow.server.VaadinService.handleRequest(VaadinService.java:1557)
	at com.vaadin.flow.server.VaadinServlet.service(VaadinServlet.java:247)
	... 28 more
Caused by: com.vaadin.flow.server.BootstrapException: Unable to read webpack stats file.
	at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.setupFrameworkLibraries(BootstrapHandler.java:893)
	at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.setupDocumentHead(BootstrapHandler.java:770)
	at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.getBootstrapPage(BootstrapHandler.java:539)
	at com.vaadin.flow.server.BootstrapHandler.synchronizedHandleRequest(BootstrapHandler.java:480)
	at com.vaadin.flow.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:40)
	at com.vaadin.flow.server.VaadinService.handleRequest(VaadinService.java:1545)
	... 29 more
Caused by: java.io.IOException: The stats file from webpack (stats.json) was not found.
The application is running in production mode.Verify that build-frontend task has executed successfully and that stats.json is on the classpath.Or switch application to development mode.
	at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.appendNpmBundle(BootstrapHandler.java:925)
	at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.setupFrameworkLibraries(BootstrapHandler.java:891)
	... 34 more

Jean-Christophe.1 · July 15, 2020, 7:15pm

It seems that you didn’t build it in production mode before running the project in production.

can you try mvn package -Pproduction ?

https://vaadin.com/docs/flow/production/tutorial-production-mode-basic.html

Okan9 · July 22, 2020, 9:15am

It seems I have a similar issue:

Java 11, Spring Boot 2.2.0(from starter), Vaadin 14.3.0, war packaging, multi module project.

Maven build with package -Pproduction with production profile(pom from starter):

[INFO]
 Running webpack ...Emitted C:\..\target\classes\META-INF\VAADIN/config/stats.json

build-frontend successfully completes.

When I start tomcat I see

INFO: Initializing AtmosphereFramework
12:08:58.996 [main]
 DEBUG com.vaadin.flow.server.startup.DevModeInitializer - Skipping DEV MODE because PRODUCTION MODE is set.

2020-07-22 12:09:48.859  INFO 22212 --- [nio-8080-exec-3]
 o.s.web.servlet.DispatcherServlet        : Completed initialization in 14 ms
2020-07-22 12:09:48.918  INFO 22212 --- [nio-8080-exec-3]
 c.v.f.s.DefaultDeploymentConfiguration   : Vaadin is running in production mode.
2020-07-22 12:09:49.935  INFO 22212 --- [nio-8080-exec-3]
 c.vaadin.flow.spring.SpringInstantiator  : The number of beans implementing 'I18NProvider' is 0. Cannot use Spring beans for I18N, falling back to the default behavior
2020-07-22 12:09:50.318 ERROR 22212 --- [nio-8080-exec-4]
 c.v.flow.server.frontend.FrontendUtils   : Cannot get the 'stats.json' from the classpath 'META-INF/VAADIN/config/stats.json'
2020-07-22 12:09:50.328 ERROR 22212 --- [nio-8080-exec-4]
 c.v.flow.server.DefaultErrorHandler      : 

com.vaadin.flow.server.BootstrapException: Unable to read webpack stats file.

Caused by: java.io.IOException: The stats file from webpack (stats.json) was not found.
The application is running in production mode.Verify that build-frontend task has executed successfully and that stats.json is on the classpath.Or switch application to development mode.

I see stats.json in …/target/classes/META-INF/VAADIN/config of parent project.

What would be the reason ?

Jean-Christophe.1 · July 23, 2020, 9:23am

Hi,

It’s hard to say but:

Is your application working in development mode?
Can you check the content of stats.json ? (if it looks empty or “good”)
Did you put your project in a specific folder (with space, special characters) and can you move it if it’s the case?
Did you change something in the pom.xml (standard build or path) ?

Okan9 · July 23, 2020, 9:59am

Hi Jean-Christophe,

Thanks for your reply.

Actually I’m trying to figure out Vaadin-Spring Boot-Multimodule project pom configuration.

What I’m trying to is having:

* a- project           aggregator pom, all the starter pom configuration is in here, stats.json is in here
* b- project-service   service module, simple pom, parent -> project
* c- project-web       webapp module, simple pom, packaging war, dependency for service, frontend folder is in here, parent ->project

Yes it is working in dev mode (goal:package), it is just the starter, In STS(Eclipse) with Tomcat
with goal: package -Pproduction profiles: production, …project…\target\classes\META-INF\VAADIN\config\stats.json has 2089 lines. When I run Tomcat(in STS), initally it says

2020-07-23 12:42:06.422  WARN 10092 --- [           main]
 c.v.f.s.c.JSR356WebsocketInitializer     : Atmosphere already initialized
2020-07-23 12:42:06.544  INFO 10092 --- [           main]
 org.apache.catalina.startup.Catalina     : Server startup in [8191]
 milliseconds

when I tried to access application in localhost from browser it says

2020-07-23 12:44:18.820  INFO 10092 --- [nio-8080-exec-3]
 o.a.c.c.C.[.[.
[/xxxxxxxxxxxxx-web]
       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2020-07-23 12:44:18.821  INFO 10092 --- [nio-8080-exec-3]
 o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2020-07-23 12:44:18.831  INFO 10092 --- [nio-8080-exec-3]
 o.s.web.servlet.DispatcherServlet        : Completed initialization in 10 ms
2020-07-23 12:44:18.891  INFO 10092 --- [nio-8080-exec-4]
 c.v.f.s.DefaultDeploymentConfiguration   : Vaadin is running in production mode.
2020-07-23 12:44:19.931  INFO 10092 --- [nio-8080-exec-4]
 c.vaadin.flow.spring.SpringInstantiator  : The number of beans implementing 'I18NProvider' is 0. Cannot use Spring beans for I18N, falling back to the default behavior
2020-07-23 12:44:20.315 ERROR 10092 --- [nio-8080-exec-4]
 c.v.flow.server.frontend.FrontendUtils   : Cannot get the 'stats.json' from the classpath 'META-INF/VAADIN/config/stats.json'
2020-07-23 12:44:20.328 ERROR 10092 --- [nio-8080-exec-4]
 c.v.flow.server.DefaultErrorHandler      : 

com.vaadin.flow.server.BootstrapException: Unable to read webpack stats file.

No special characters - But yes some specific folders, explained below
Not changed build path, build section and profile section of pom
- but added ${project.artifactId}
- added spring-boot-starter-tomcat dependency
- added modules for my configuration
Meanwhile I have moved my generated war package file to my test server and when I start tomcat I experience different case:Caused by: java.lang.IllegalArgumentException: More than one fragment with the name [spring_web]
was found. This is not legal with relative ordering.

I guess I have a configuration issue with pom.

Many thanks

Okan9 · July 23, 2020, 11:09am

Just downloaded fresh my-starter-project from vaadin.com, imported and changed only the packaging to war and java version to 11.

Build goal:package - OK , run on tomcat - OK, I can access application from http://localhost:8080/my-starter-project/ and it works
Clean project and then Build goal:package -Pproduction Profiles: production - OK
Added -Dapplication.properties.path server configuration and run on tomcat again the same issue even with the basic starter download:

2020-07-23 14:03:36.928  INFO 21848 --- [nio-8080-exec-2]
 o.a.c.c.C.[.[.
[/my-starter-project]
      : Initializing Spring DispatcherServlet 'dispatcherServlet'
2020-07-23 14:03:36.929  INFO 21848 --- [nio-8080-exec-2]
 o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2020-07-23 14:03:36.941  INFO 21848 --- [nio-8080-exec-2]
 o.s.web.servlet.DispatcherServlet        : Completed initialization in 12 ms
2020-07-23 14:03:36.999  INFO 21848 --- [nio-8080-exec-3]
 c.v.f.s.DefaultDeploymentConfiguration   : Vaadin is running in production mode.
2020-07-23 14:03:38.107  INFO 21848 --- [nio-8080-exec-3]
 c.vaadin.flow.spring.SpringInstantiator  : The number of beans implementing 'I18NProvider' is 0. Cannot use Spring beans for I18N, falling back to the default behavior
2020-07-23 14:03:38.551 ERROR 21848 --- [nio-8080-exec-3]
 c.v.flow.server.frontend.FrontendUtils   : Cannot get the 'stats.json' from the classpath 'META-INF/VAADIN/config/stats.json'
2020-07-23 14:03:38.563 ERROR 21848 --- [nio-8080-exec-3]
 c.v.flow.server.DefaultErrorHandler      : 

com.vaadin.flow.server.BootstrapException: Unable to read webpack stats file.

Did I do something missing ?

Jean-Christophe.1 · July 23, 2020, 11:30am

Hi,

Can you add the exact steps you did (the command you ran)?

mvn package
mvn spring-boot:run → OK
mvn package -Pproduction
mvn spring-boot:run -Dvaadin.productionMode=true → OK

Then I’m not sure about your last command?

Okan9 · July 23, 2020, 4:26pm

Hi,

Actually, I’m trying to run sample starter in tomcat in STS/Eclipse.

I found that subsequent builds(Dev-mode then Prod-mode) creates the issue, but what would be the residual information which cannot be deleted by Clean ?

Here the scenario, it’s a bit long though:

I have cleared all the workspace and downloaded fresh my-starter-project and imported as Maven project
In pom.xml, I have changed packaging to war, java to 11 and added finalName for simple war file name and performed Maven - Update project
From Run - Run configurations menu I have created Maven Build configuration Development Build with goal package and executed the build . Final war was 30MB in size.
I have added Tomcat server to Servers in STS/Eclipse and added my-starter-project to server with Run as Run on server but cancelled run due to missing application properties.
Then, again from Run Run configurations I have edited Tomcat profile and added -Dapplication.properties.path=“file:///C:/xxxx/STS4470-NewApp-WS/my-starter-project/src/main/resources/application.properties” to point application properties file.
And started the Tomcat in STS/Eclipse
While starting Tomcat I see lots of messages under DEBUG dev-updater and DEBUG dev-webpack and it has started normally and
I could access it through localhost:8080/my-starter-project, all is perfect - dev mode
I have stopped Tomcat server in my local STS/Eclipse
I have created duplicate Maven Build configuration from Run - Run configurations and chagned the goal to package -Pproduction and Profiles: production and run it.
Project - Clean - Clean all projects
Run the Production Build. This time webpack ran during build. Final war was 33MB in size.
I started tomcat, no errors during startup. But when I tried to access localhost:8080/my-starter-project I got Unable to read webpack stats file, on my browser and in server log.

So I guess that an issue happens when -Pproduction build made after normal build. In order to check:

I have performed Project - Clean - Clean all projects and change the goal to clean package -Pproduction and rebuilt.
Build completes but this time I have experienced the case explained in https://github.com/vaadin/flow/issues/7985 and added Validator exclusions to STS/Eclipse and Maven Update project again
I got thousands of Warnings for generated html files in node_modules and added HTML Exclusion also for validation and after Maven Update project I see only two Warnings for serialVersionUID in MainView and GreetService
Then assuming with all is OK I have re-Launched Tomcat.
No way! Started webpack-dev-server - “Vaadin is running in DEBUG MODE” ?? goal clean -Pproduction and webpack ?

I could not be sure if my goal is correct but it was, removed target folder contents and retried the build, and relaunched the tomcat, now it turned to Prod mode but again with The stats file from webpack (stats.json) was not found. error on browser and in the log.

As a final attempt, I have cleared all the workspace again(deleted all the files in STS/Eclipse workspae), and re-execute 1-13 but this time with -Pproduction build for the first time and never built for development.

Suprise, in local it was ok with Production mode, no errors on browser it says hello anonymous user. I have transferred war file to my server and it has worked there also and accessible from browser.

So my experience is development mode, somehow persists in somewhere, for war packaging, even Project - clean, maven clean or removing target folder not helped.

Could be the clean goal before package is not executed from Run configuration ? Should I add maven-clean-plugin to production Profile section in pom.xml ?

but even with removing the all the contents of target folder did not help(resulting to not found stats.json)?

It seems the only way to run Production mode was to build first with Production and continue with it.

Maybe I have a small mistake/missing point in the above flow but I could not figure out what.

Thanks in advance.

Jean-Christophe.1 · July 24, 2020, 1:27pm

That’s a lot of tests.

I’m thinking of a synchronization problem of the files you have on your file system and the files in your workspace. I had this kind of errors when I used eclipse (but I’m using IntelliJ most of the time).

But I don’t know. Most of the time I’m not switching from productionMode to devMode and to try productionMode I generally use the command line (to avoid this kind of cache/ error).

Okan9 · July 24, 2020, 2:37pm

It is simply a new folder as a workspace and clean import of a sample project starter, that is strange.

I guessed the issue is about m2e but even with moving war file to server did not change the result. It seems problem happens during the build.

Actually I have also tested the following case to keep on PROD mode and prevent to switch to dev mode:

Successfully built and run the sample application in PROD mode on server
Changed something in java codes, server auto restarts and change was in effect
Changed the styles simply changing lumo-base-color to lumo-success-color for the text field background in css.
Re-execute clean build as the PROD mode requires
Re-deploy on server - Nothing changes for text field background color.
I have performed just Projects - Clean and then the same build configuration for PROD
When I restarted the server it ran in DEV MODE even I did not have any build configuration without -Pproduction and did not build without -Pproduction before. But the style change was in effect

So no way to keep in PROD mode with changing styles…

psc1952 · October 20, 2020, 4:08pm

Just upgraded to Vaadin 14.4.1 and we are getting this after login:

com.vaadin.flow.server.BootstrapException: Unable to read webpack stats file.
at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.setupFrameworkLibraries(BootstrapHandler.java:893) ~[flow-server-2.3.7.jar:2.3.7]

at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.setupDocumentHead(BootstrapHandler.java:770) ~[flow-server-2.3.7.jar:2.3.7]

at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.getBootstrapPage(BootstrapHandler.java:539) ~[flow-server-2.3.7.jar:2.3.7]

at com.vaadin.flow.server.BootstrapHandler.synchronizedHandleRequest(BootstrapHandler.java:480) ~[flow-server-2.3.7.jar:2.3.7]

...

This does not occur using Vaadin 14.3.9. Any help will be greatly appreciated.

psc1952 · November 29, 2020, 6:08pm

Okay, no response…let’s try again…
Just upgraded to 14.4.3 and now getting this error:

2020-11-29 10:01:33.141 ERROR 22375 — [0.1-8080-exec-7]
o.a.c.c.C.[.[.[.[dispatcherServlet]
: Servlet.service() for servlet [dispatcherServlet]
in context with path
[/development] threw exception [com.vaadin.flow.server.ServiceException: com.vaadin.flow.server.BootstrapException: Unable to read webpack stats file.]
with root cause

java.net.ConnectException: Connection refused (Connection refused)
at java.base/java.net.PlainSocketImpl.socketConnect(Native Method) ~[na:na]

at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399) ~[na:na]

at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242) ~[na:na]

at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224) ~[na:na]

...

Guess we’ll fall back to version 14.3.9 and wait to see if there is anyone who will help us with this issue.

mgrankvi · November 30, 2020, 7:28am

The stack trace should have more of a root cause e.g. WebpackConnectionException or IOException with extra information.

Did the webpack build succeed and is the webpackDevServer up and running?
There should be in the log a line like ------------------ Frontend compilation failed. ----------------- or ----------------- Frontend compiled successfully. -----------------
If it has failed by scrolling up should give some more information on why it failed.

Else if the dev server is up and running try connecting to the devServer on the port printed before the execution should look something like i ?wds?: Project is running at http://localhost:49905/webpack-dev-server/ (Note the port is not static and changes between runs) the url should give a directory serving of config and going to http://localhost:49905/assetsByChunkName should return a string looking like {"bundle":"build/vaadin-bundle-6fea68761ed8139e41bf.cache.js","devmodeGizmo":"build/vaadin-devmodeGizmo-ab0c65ccc111fa465397.cache.js","export":"build/vaadin-export-b48171422a92f3d768fc.cache.js"}

psc1952 · November 30, 2020, 2:32pm

Just upgraded to Vaadin 14.4.1 and we are getting this after login:

com.vaadin.flow.server.BootstrapException: Unable to read webpack stats file.
at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.setupFrameworkLibraries(BootstrapHandler.java:893) ~[flow-server-2.3.7.jar:2.3.7]

at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.setupDocumentHead(BootstrapHandler.java:770) ~[flow-server-2.3.7.jar:2.3.7]

at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.getBootstrapPage(BootstrapHandler.java:539) ~[flow-server-2.3.7.jar:2.3.7]

at com.vaadin.flow.server.BootstrapHandler.synchronizedHandleRequest(BootstrapHandler.java:480) ~[flow-server-2.3.7.jar:2.3.7]

...

This does not occur using Vaadin 14.3.9. Any help will be greatly appreciated.

psc1952 · November 30, 2020, 3:16pm

Hi Mikael,

Rebuild our project using Vaadin 14.4.3 and get the following or start up (development mode):

npm WARN deprecated fsevents@1.2.13: fsevents 1 will break on node v14+ and could be using insecure binaries. Upgrade to fsevents 2.
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@^1.2.7 (node_modules/webpack-dev-server/node_modules/chokidar/node_modules/fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.2.13: wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"x64"})
npm WARN no-name@ No description
npm WARN no-name@ No repository field.
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.13 (node_modules/@babel/cli/node_modules/fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.2.13: wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"x64"})
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@1.2.13 (node_modules/watchpack-chokidar2/node_modules/fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@1.2.13: wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"x64"})
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: fsevents@2.1.3 (node_modules/fsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for fsevents@2.1.3: wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"x64"})

2020-11-30 06:54:04.043  INFO 17506 --- [  restartedMain]
 dev-updater                              : Frontend dependencies resolved successfully.
2020-11-30 06:54:04.044  INFO 17506 --- [  restartedMain]
 dev-updater                              : Copying frontend resources from jar files ...
2020-11-30 06:54:04.061  INFO 17506 --- [  restartedMain]
 dev-updater                              : Visited 18 resources. Took 17 ms.
2020-11-30 06:54:04.133  INFO 17506 --- [  restartedMain]
 dev-updater                              : Updated /home/pcorbett/corbettcode/clients/MedWorxs/onerev14/JavaModules/onerev-application/target/frontend/generated-flow-imports.js

------------------ Starting Frontend compilation. ------------------
2020-11-30 06:54:04.233  INFO 17506 --- [  restartedMain]
 dev-webpack                              : Running webpack to compile frontend resources. This may take a moment, please stand by...
2020-11-30 06:54:06.564  INFO 17506 --- [  restartedMain]
 dev-webpack                              : Started webpack-dev-server. Time: 2332ms
Vaadin application has been deployed and started to the context path "/development".

We get the login screen, logged in and then received this error:

2020-11-30 06:58:30.631 DEBUG 17506 --- [0.1-8080-exec-7]
 o.a.u.c.n.ViewSecurityRegistrator        : Granting access to view [class onerev.app.ui.dashboard.DashboardView]

2020-11-30 06:58:30.704 DEBUG 17506 --- [0.1-8080-exec-7]
 o.a.ui.common.error.SessionErrorHandler  : Handling uncaught exception

com.vaadin.flow.server.BootstrapException: Unable to read webpack stats file.
	at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.setupFrameworkLibraries(BootstrapHandler.java:893) ~[flow-server-2.3.7.jar:2.3.7]

	at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.setupDocumentHead(BootstrapHandler.java:770) ~[flow-server-2.3.7.jar:2.3.7]

	at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.getBootstrapPage(BootstrapHandler.java:539) ~[flow-server-2.3.7.jar:2.3.7]

	at com.vaadin.flow.server.BootstrapHandler.synchronizedHandleRequest(BootstrapHandler.java:480) ~[flow-server-2.3.7.jar:2.3.7]

	at com.vaadin.flow.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:40) ~[flow-server-2.3.7.jar:2.3.7]

	at com.vaadin.flow.server.VaadinService.handleRequest(VaadinService.java:1545) ~[flow-server-2.3.7.jar:2.3.7]

	at com.vaadin.flow.server.VaadinServlet.service(VaadinServlet.java:247) ~[flow-server-2.3.7.jar:2.3.7]

	at com.vaadin.flow.spring.SpringServlet.service(SpringServlet.java:108) ~[vaadin-spring-12.3.1.jar:na]

...
Caused by: java.net.ConnectException: Connection refused (Connection refused)
	at java.base/java.net.PlainSocketImpl.socketConnect(Native Method) ~[na:na]

	at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399) ~[na:na]

	at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242) ~[na:na]

	at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224) ~[na:na]

	at java.base/java.net.Socket.connect(Socket.java:591) ~[na:na]

	at java.base/sun.net.NetworkClient.doConnect(NetworkClient.java:177) ~[na:na]

	at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:474) ~[na:na]

	at java.base/sun.net.www.http.HttpClient.openServer(HttpClient.java:569) ~[na:na]

	at java.base/sun.net.www.http.HttpClient.<init>(HttpClient.java:242) ~[na:na]

	at java.base/sun.net.www.http.HttpClient.New(HttpClient.java:341) ~[na:na]

	at java.base/sun.net.www.http.HttpClient.New(HttpClient.java:362) ~[na:na]

	at java.base/sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:1242) ~[na:na]

	at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1181) ~[na:na]

	at java.base/sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:1075) ~[na:na]

	at java.base/sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:1009) ~[na:na]

	at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1581) ~[na:na]

	at java.base/sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1509) ~[na:na]

	at java.base/java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:527) ~[na:na]

	at com.vaadin.flow.server.frontend.FrontendUtils.getStatsAssetsByChunkName(FrontendUtils.java:532) ~[flow-server-2.3.7.jar:2.3.7]

	at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.appendNpmBundle(BootstrapHandler.java:909) ~[flow-server-2.3.7.jar:2.3.7]

	at com.vaadin.flow.server.BootstrapHandler$BootstrapPageBuilder.setupFrameworkLibraries(BootstrapHandler.java:891) ~[flow-server-2.3.7.jar:2.3.7]

	... 92 common frames omitted

psc1952 · November 30, 2020, 3:42pm

Additional Information

rebuilt using Vaadin 14.3.9

ran npm install in node_modules/webpack-dev-server:

/usr/local/bin/node /usr/local/lib/node_modules/npm/bin/npm-cli.js install --scripts-prepend-node-path=auto
npm WARN deprecated superagent@3.8.3: Please note that v5.0.1+ of superagent removes User-Agent header by default, therefore you may need to add it yourself (e.g. GitHub blocks requests without a User-Agent header).  This notice will go away with v5.0.2+ once it is released.
npm WARN deprecated core-js@2.6.12: core-js@<3 is no longer maintained and not recommended for usage due to the number of issues. Please, upgrade your dependencies to the actual version of core-js@3.
npm WARN deprecated fsevents@1.2.13: fsevents 1 will break on node v14+ and could be using insecure binaries. Upgrade to fsevents 2.
npm WARN deprecated left-pad@1.3.0: use String.prototype.padStart()
npm WARN deprecated request@2.88.2: request has been deprecated, see https://github.com/request/request/issues/3142
npm WARN deprecated request-promise-native@1.0.9: request-promise-native has been deprecated because it extends the now deprecated request package, see https://github.com/request/request/issues/3142
npm WARN deprecated har-validator@5.1.5: this library is no longer supported

> husky@3.1.0 install /home/pcorbett/corbettcode/clients/MedWorxs/onerev14/JavaModules/onerev-application/node_modules/webpack-dev-server/node_modules/husky
> node husky install

husky > Setting up git hooks
Trying to install from node_modules directory, skipping Git hooks installation.
husky > Done

> puppeteer@1.20.0 install /home/pcorbett/corbettcode/clients/MedWorxs/onerev14/JavaModules/onerev-application/node_modules/webpack-dev-server/node_modules/puppeteer
> node install.js

Downloading Chromium r686378 - 114 Mb [====================]
 100% 0.0s 
Chromium downloaded to /home/pcorbett/corbettcode/clients/MedWorxs/onerev14/JavaModules/onerev-application/node_modules/webpack-dev-server/node_modules/puppeteer/.local-chromium/linux-686378

> core-js@2.6.12 postinstall /home/pcorbett/corbettcode/clients/MedWorxs/onerev14/JavaModules/onerev-application/node_modules/webpack-dev-server/node_modules/core-js
> node -e "try{require('./postinstall')}catch(e){}"

Thank you for using core-js ( https://github.com/zloirock/core-js ) for polyfilling JavaScript standard library!

The project needs your help! Please consider supporting of core-js on Open Collective or Patreon: 
> https://opencollective.com/core-js 
> https://www.patreon.com/zloirock 

Also, the author of core-js ( https://github.com/zloirock ) is looking for a good job -)


> husky@3.1.0 postinstall /home/pcorbett/corbettcode/clients/MedWorxs/onerev14/JavaModules/onerev-application/node_modules/webpack-dev-server/node_modules/husky
> opencollective-postinstall || exit 0

Thank you for using husky!
If you rely on this package, please consider supporting our open collective:
> https://opencollective.com/husky/donate


> webpack-dev-server@3.10.3 prepare /home/pcorbett/corbettcode/clients/MedWorxs/onerev14/JavaModules/onerev-application/node_modules/webpack-dev-server
> rimraf ./ssl/*.pem && npm run build:client


> webpack-dev-server@3.10.3 build:client /home/pcorbett/corbettcode/clients/MedWorxs/onerev14/JavaModules/onerev-application/node_modules/webpack-dev-server
> rimraf ./client/* && npm-run-all -s -l -p "build:client:**"

[build:client:index  ]
 
[build:client:index  ]
 > webpack-dev-server@3.10.3 build:client:index /home/pcorbett/corbettcode/clients/MedWorxs/onerev14/JavaModules/onerev-application/node_modules/webpack-dev-server
[build:client:index  ]
 > webpack ./client-src/default/index.js -o client/index.bundle.js --color --config client-src/default/webpack.config.js
[build:client:index  ]
 
[build:client:live   ]
 
[build:client:live   ]
 > webpack-dev-server@3.10.3 build:client:live /home/pcorbett/corbettcode/clients/MedWorxs/onerev14/JavaModules/onerev-application/node_modules/webpack-dev-server
[build:client:live   ]
 > webpack ./client-src/live/index.js -o client/live.bundle.js --color --config client-src/live/webpack.config.js
[build:client:live   ]
 
[build:client:sockjs ]
 
[build:client:sockjs ]
 > webpack-dev-server@3.10.3 build:client:sockjs /home/pcorbett/corbettcode/clients/MedWorxs/onerev14/JavaModules/onerev-application/node_modules/webpack-dev-server
[build:client:sockjs ]
 > webpack ./client-src/sockjs/index.js -o client/sockjs.bundle.js --color --config client-src/sockjs/webpack.config.js
[build:client:sockjs ]
 
[build:client:clients]
 
[build:client:clients]
 > webpack-dev-server@3.10.3 build:client:clients /home/pcorbett/corbettcode/clients/MedWorxs/onerev14/JavaModules/onerev-application/node_modules/webpack-dev-server
[build:client:clients]
 > babel client-src/clients --out-dir client/clients
[build:client:clients]
 
[build:client:default]
 
[build:client:default]
 > webpack-dev-server@3.10.3 build:client:default /home/pcorbett/corbettcode/clients/MedWorxs/onerev14/JavaModules/onerev-application/node_modules/webpack-dev-server
[build:client:default]
 > babel client-src/default --out-dir client --ignore "./client-src/default/*.config.js"
[build:client:default]
 
[build:client:default]
 babel:
[build:client:clients]
 babel:
[build:client:default]
   client-src/default does not exist
[build:client:clients]
   client-src/clients does not exist
[build:client:default]
 npm ERR! code ELIFECYCLE
[build:client:default]
 npm ERR! errno 2
[build:client:clients]
 npm ERR! code ELIFECYCLE
[build:client:clients]
 npm ERR! errno 2
[build:client:default]
 npm ERR! webpack-dev-server@3.10.3 build:client:default: `babel client-src/default --out-dir client --ignore "./client-src/default/*.config.js"`
[build:client:default]
 npm ERR! Exit status 2
[build:client:default]
 npm ERR! 
[build:client:default]
 npm ERR! Failed at the webpack-dev-server@3.10.3 build:client:default script.
[build:client:default]
 npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
[build:client:clients]
 npm ERR! webpack-dev-server@3.10.3 build:client:clients: `babel client-src/clients --out-dir client/clients`
[build:client:clients]
 npm ERR! Exit status 2
[build:client:clients]
 npm ERR! 
[build:client:clients]
 npm ERR! Failed at the webpack-dev-server@3.10.3 build:client:clients script.
[build:client:clients]
 npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
[build:client:clients]
 
[build:client:clients]
 npm ERR! A complete log of this run can be found in:
[build:client:clients]
 npm ERR!     /home/pcorbett/.npm/_logs/2020-11-30T15_38_48_390Z-debug.log
[build:client:default]
 
[build:client:default]
 npm ERR! A complete log of this run can be found in:
[build:client:default]
 npm ERR!     /home/pcorbett/.npm/_logs/2020-11-30T15_38_48_390Z-debug.log
ERROR: "build:client:clients" exited with 2.
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! webpack-dev-server@3.10.3 build:client: `rimraf ./client/* && npm-run-all -s -l -p "build:client:**"`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the webpack-dev-server@3.10.3 build:client script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/pcorbett/.npm/_logs/2020-11-30T15_38_48_429Z-debug.log
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! webpack-dev-server@3.10.3 prepare: `rimraf ./ssl/*.pem && npm run build:client`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the webpack-dev-server@3.10.3 prepare script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/pcorbett/.npm/_logs/2020-11-30T15_38_48_472Z-debug.log

Process finished with exit code 1

mgrankvi · December 1, 2020, 6:35am

As the dev server seems to have started you should try to connect to it.
for the 14 series you need to put the log level to debug and find a line looking something like:
2020-12-01 08:21:38.094 DEBUG 11924 --- [ webpack] dev-webpack : [38;5;35mi ?wds?: Project is running at http://localhost:53412/webpack-dev-server/ and try to connect to the devServer specially what you would want is the http://localhost:PORT/assetsByChunkName

psc1952 · December 1, 2020, 7:41am

------------------ Starting Frontend compilation. ------------------
2020-11-30 23:36:57.456 DEBUG 92387 --- [  restartedMain]
 dev-webpack                              : 
\ 
    ./node/node \ 
    ./node_modules/webpack-dev-server/bin/webpack-dev-server.js \ 
    --config \ 
    ./webpack.config.js --port 45219 \ 
    --watchDogPort=44023 -d --inline=false 

2020-11-30 23:36:57.457  INFO 92387 --- [  restartedMain]
 dev-webpack                              : Running webpack to compile frontend resources. This may take a moment, please stand by...

2020-11-30 23:36:57.973 DEBUG 92387 --- [        webpack]
 dev-webpack                              : ℹ ｢wds｣: Project is running at http://localhost:45219/webpack-dev-server/
2020-11-30 23:36:57.973 DEBUG 92387 --- [        webpack]
 dev-webpack                              : ℹ ｢wds｣: webpack output is served from /VAADIN/
2020-11-30 23:36:57.973 DEBUG 92387 --- [        webpack]
 dev-webpack                              : ℹ ｢wds｣: Content not from webpack is served from /home/pcorbett/corbettcode/clients/MedWorxs/onerev14/JavaModules/onerev-application/target/classes/META-INF/VAADIN, src/main/webapp

2020-11-30 23:36:59.659 DEBUG 92387 --- [        webpack]
 dev-webpack                              :          Serving the 'stats.json' file dynamically.
2020-11-30 23:36:59.686 DEBUG 92387 --- [        webpack]
 dev-webpack                              : ℹ ｢wdm｣: Hash: e0511d3332a22124cf72
2020-11-30 23:36:59.686 DEBUG 92387 --- [        webpack]
 dev-webpack                              : Version: webpack 4.42.0
2020-11-30 23:36:59.686 DEBUG 92387 --- [        webpack]
 dev-webpack                              : Time: 1701ms
2020-11-30 23:36:59.686 DEBUG 92387 --- [        webpack]
 dev-webpack                              : Built at: 11/30/2020 11:36:59 PM
2020-11-30 23:36:59.686 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                                                                      Asset       Size  Chunks                                Chunk Names
2020-11-30 23:36:59.686 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                          build/vaadin-bundle-0f41af08d09d70b98d96.cache.js   15.4 MiB  bundle  [emitted]
 [immutable]
  [big]
  bundle
2020-11-30 23:36:59.686 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                           build/vaadin-gizmo-41af0f1bf94ebce99bd1.cache.js    431 KiB   gizmo  [emitted]
 [immutable]
         gizmo
2020-11-30 23:36:59.686 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                                           build/webcomponentsjs/LICENSE.md   1.52 KiB          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                                            build/webcomponentsjs/README.md   10.5 KiB          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                          build/webcomponentsjs/bundles/webcomponents-ce.js     20 KiB          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                      build/webcomponentsjs/bundles/webcomponents-ce.js.map    121 KiB          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                    build/webcomponentsjs/bundles/webcomponents-sd-ce-pf.js    114 KiB          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                build/webcomponentsjs/bundles/webcomponents-sd-ce-pf.js.map    671 KiB          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                       build/webcomponentsjs/bundles/webcomponents-sd-ce.js   85.7 KiB          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                   build/webcomponentsjs/bundles/webcomponents-sd-ce.js.map    543 KiB          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                          build/webcomponentsjs/bundles/webcomponents-sd.js   66.7 KiB          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                      build/webcomponentsjs/bundles/webcomponents-sd.js.map    423 KiB          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                       build/webcomponentsjs/custom-elements-es5-adapter.js  954 bytes          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                                         build/webcomponentsjs/package.json   2.45 KiB          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              : build/webcomponentsjs/src/entrypoints/custom-elements-es5-adapter-index.js  659 bytes          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :        build/webcomponentsjs/src/entrypoints/webcomponents-bundle-index.js   1.66 KiB          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :            build/webcomponentsjs/src/entrypoints/webcomponents-ce-index.js  675 bytes          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :         build/webcomponentsjs/src/entrypoints/webcomponents-sd-ce-index.js  860 bytes          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :      build/webcomponentsjs/src/entrypoints/webcomponents-sd-ce-pf-index.js   1.22 KiB          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :            build/webcomponentsjs/src/entrypoints/webcomponents-sd-index.js  767 bytes          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                              build/webcomponentsjs/webcomponents-bundle.js    115 KiB          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                          build/webcomponentsjs/webcomponents-bundle.js.map    673 KiB          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              :                              build/webcomponentsjs/webcomponents-loader.js   6.13 KiB          [emitted]
                     
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              : Entrypoint bundle [big]
 = build/vaadin-bundle-0f41af08d09d70b98d96.cache.js
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              : Entrypoint gizmo = build/vaadin-gizmo-41af0f1bf94ebce99bd1.cache.js
2020-11-30 23:36:59.687 DEBUG 92387 --- [        webpack]
 dev-webpack                              : [../node_modules/@polymer/iron-icon/iron-icon.js]
 5.5 KiB {bundle} [built]

2020-11-30 23:36:59.688 DEBUG 92387 --- [        webpack]
 dev-webpack                              : [../node_modules/@polymer/iron-list/iron-list.js]
 59.3 KiB {bundle} [built]

2020-11-30 23:36:59.688 DEBUG 92387 --- [        webpack]
 dev-webpack                              : [../node_modules/@polymer/paper-ripple/paper-ripple.js]
 18.3 KiB {bundle} [built]

2020-11-30 23:36:59.688 DEBUG 92387 --- [        webpack]
 dev-webpack                              : [../node_modules/@vaadin/flow-frontend/VaadinDevmodeGizmo.js]
 32.7 KiB {gizmo} {bundle} [built]

2020-11-30 23:36:59.688 DEBUG 92387 --- [        webpack]
 dev-webpack                              : [../node_modules/@vaadin/flow-frontend/com/github/appreciated/card/clickable-card.js]
 3.71 KiB {bundle} [built]

2020-11-30 23:36:59.688 DEBUG 92387 --- [        webpack]
 dev-webpack                              : [../node_modules/@vaadin/flow-frontend/com/github/appreciated/card/content-card.js]
 1.34 KiB {bundle} [built]

2020-11-30 23:36:59.688 DEBUG 92387 --- [        webpack]
 dev-webpack                              : [../node_modules/@vaadin/flow-frontend/com/github/appreciated/card/stateful-card.js]
 3.41 KiB {bundle} [built]

2020-11-30 23:36:59.688 DEBUG 92387 --- [        webpack]
 dev-webpack                              : [../node_modules/@vaadin/flow-frontend/comboBoxConnector-es6.js]
 417 bytes {bundle} [built]

2020-11-30 23:36:59.688 DEBUG 92387 --- [        webpack]
 dev-webpack                              : [../node_modules/@vaadin/flow-frontend/comboBoxConnector.js]
 17 KiB {bundle} [built]

2020-11-30 23:36:59.688 DEBUG 92387 --- [        webpack]
 dev-webpack                              : [../node_modules/@vaadin/flow-frontend/contextMenuConnector-es6.js]
 319 bytes {bundle} [built]

2020-11-30 23:36:59.688 DEBUG 92387 --- [        webpack]
 dev-webpack                              : [../node_modules/@vaadin/flow-frontend/contextMenuConnector.js]
 4.04 KiB {bundle} [built]

2020-11-30 23:36:59.688 DEBUG 92387 --- [        webpack]
 dev-webpack                              : [../node_modules/@vaadin/flow-frontend/datepickerConnector.js]
 6.67 KiB {bundle} [built]

2020-11-30 23:36:59.688 DEBUG 92387 --- [        webpack]
 dev-webpack                              : [../node_modules/@vaadin/flow-frontend/dndConnector-es6.js]
 29 bytes {bundle} [built]

2020-11-30 23:36:59.688 DEBUG 92387 --- [        webpack]
 dev-webpack                              : [../node_modules/@vaadin/flow-frontend/dndConnector.js]
 4.19 KiB {bundle} [built]

2020-11-30 23:36:59.688 DEBUG 92387 --- [        webpack]
 dev-webpack                              : [../target/frontend/generated-flow-imports.js]
 6.67 KiB {bundle} [built]

2020-11-30 23:36:59.688 DEBUG 92387 --- [        webpack]
 dev-webpack                              :     + 563 hidden modules
2020-11-30 23:36:59.688 DEBUG 92387 --- [        webpack]
 dev-webpack                              : ℹ ｢wdm｣: Compiled successfully.
2020-11-30 23:36:59.688 DEBUG 92387 --- [        webpack]
 dev-webpack                              : 
----------------- Frontend compiled successfully. -----------------
2020-11-30 23:36:59.688  INFO 92387 --- [  restartedMain]
 dev-webpack                              : Started webpack-dev-server. Time: 2232ms

2020-11-30 23:37:00.097 DEBUG 92387 --- [        webpack]
 dev-webpack                              : Watchdog connection error. Terminating webpack process...

psc1952 · December 1, 2020, 8:45am

This is a follow up to the message above:

Switched to Vaadin 14.4.4
Rebuild entire project
Deleted node_modules directory

So far, everything seems to be working.

mgrankvi · December 1, 2020, 9:04am

If you try to start the dev server with:

./node/node \ 
    ./node_modules/webpack-dev-server/bin/webpack-dev-server.js \ 
    --config \ 
    ./webpack.config.js --port 45219 \ 
    --watchDogPort=44023 -d --inline=false

Can you then connect to the server after it starts? As it would seem that the watchdog can’t get
a connection to the dev-server and then shuts it down as unreachable.

The exception comes from the lines


if (watchDogPort) {
  watchDogPort = watchDogPort.substr(watchDogPrefix.length);
  const runWatchDog = () => {
    const client = new require('net').Socket();
    client.setEncoding('utf8');
    client.on('error', function () {
      console.log("Watchdog connection error. Terminating webpack process...");
      client.destroy();
      process.exit(0);
    });
    client.on('close', function () {
      client.destroy();
      runWatchDog();
    });

    client.connect(watchDogPort, 'localhost');
  }
  runWatchDog();
}

in webpack.generated.js where we try to connec to the given port on localhost.