WAR
A Ktor application can be run and deployed inside servlet containers that include Tomcat and Jetty. To deploy inside a servlet container, you need to generate a WAR archive and then deploy it to a server or a cloud service that supports WARs.
In this topic, we'll show you how to:
configure Ktor to use it in a servlet application;
apply Gretty and War plugins for running and packaging WAR applications;
run a Ktor servlet application;
generate and deploy a WAR archive.
Configure Ktor in a servlet application
Ktor allows you to create and start a server with the desired engine (such as Netty, Jetty, or Tomcat) right in the application. In this case, your application has control over engine settings, connection, and SSL options.
In contrast to the approach above, a servlet container should control the application lifecycle and connection settings. Ktor provides a special ServletApplicationEngine engine that delegates control over your application to a servlet container.
Add dependencies
To use Ktor in a servlet application, you need to include the ktor-server-servlet-jakarta
artifact in the build script:
If you use the 9.x or earlier version of Tomcat/Jetty, add the ktor-server-servlet
artifact instead.
Configure a servlet
To register a Ktor servlet in your application, open the WEB-INF/web.xml
file and assign ServletApplicationEngine
to the servlet-class
attribute:
Then, configure the URL pattern for this servlet:
Configure Gretty
The Gretty plugin allows you to run a servlet application on Jetty and Tomcat. To install this plugin, open the build.gradle.kts
file and add the following code to the plugins
block:
Then, you can configure it in the gretty
block as follows:
Finally, configure the run
task:
Configure War
The War plugin allows you to generate WAR archives. You can install it by adding the following line to the plugins
block in your build.gradle.kts
file:
Run an application
You can run a servlet application with the configured Gretty plugin by using the run
task. For example, the following command runs the jetty-war example:
Generate and deploy a WAR archive
To generate a WAR file with your application using the War plugin, execute the war
task. For the jetty-war example, a command looks as follows:
The jetty-war.war
is created in the build/libs
directory. You can deploy the generated archive inside a servlet container by copying it to the jetty/webapps
directory. For instance, a Dockerfile
below shows how to run the created WAR inside a Jetty or Tomcat servlet container:
You can find the complete examples here: jetty-war and tomcat-war.