index.md

Child Process extension for Vert.x

Child Process is a Vert.x component for spawning OS child processes.

• based on https://github.com/brettwooldridge/NuProcess Low-overhead, non-blocking I/O, external Process implementation for Java.
• standard streams are fully non blocking
• spawned process can be killed

Using Child Process

To use Child Process, add the following dependency to the dependencies section of your build descriptor:

• Maven (in your pom.xml):

<dependency>
  <groupId>${maven.groupId}</groupId>
  <artifactId>${maven.artifactId}</artifactId>
  <version>${maven.version}</version>
</dependency>

• Gradle (in your build.gradle file):

dependencies {
  compile '${maven.groupId}:${maven.artifactId}:${maven.version}'
}

Spawning child processes

You can spawn child processes with the {@link com.julienviet.childprocess.Process#create} and {@link com.julienviet.childprocess.ProcessBuilder#start} methods:

{@link examples.Examples#ex01}

the future returned by start completes when the process has started or failed

you can give arguments to child processes

{@link examples.Examples#ex02}

by default child processes use the current process environment options, you can pass key-value pairs as new environment variables

{@link examples.Examples#ex03}

{@link com.julienviet.childprocess.Process#env()} gives you the current process environment key-value pairs

{@link examples.Examples#ex04}

By default, the child processes uses the current process current working directory, the {@link com.julienviet.childprocess.ProcessOptions#setCwd(java.lang.String)} option overrides it

{@link examples.Examples#ex05}

Interacting with child processes

The child process streams are available as

• {@link com.julienviet.childprocess.Process#stdin()}
• {@link com.julienviet.childprocess.Process#stdout()}
• {@link com.julienviet.childprocess.Process#stderr()}

{@link examples.Examples#ex10}

Calling {@link com.julienviet.childprocess.Process#kill()} kills the child process, on POSIX it sends the SIGTERM signal.

{@link examples.Examples#ex30}

Child processes can also be forcibly killed

{@link examples.Examples#ex31}

Child process lifecycle

You can be aware of the child process termination

{@link examples.Examples#ex20}