|| operator in Gradle Task commandLine-CodePudding

Good day. It is necessary to make a decision to run the second command based on the results of the previous one.

I need to check if npm package is installed and if it doesn't exist start installing. npm list -g package (if the package does not exist, this command will return a value different from 0) and npm install -g package commands are used for the issue. It is easy to execute the logic in a terminal using || operator:

npm list -g package || npm install -g package

Then I created installPackage task in gradle.build file:

task installPackage(type: Exec) {
  commandLine 'npm', 'list', '-g', 'package', '||', 'npm', 'install', '-g', 'package'
}

And none of the commands work. In fact, the result is displayed as if npm list -g command was used.

Is there a way to do this without using third-party tools or plugins? What options could be used? Thanks a lot

CodePudding user response：

There is a question about execute multiple commands Gradle -- execute multiple commands from task, but it doesn't support && or ||. Just pick from below solutions that make sense to you. Personally I prefer solution 1.

1. Put your command in a script and call the script

More flexible
More readable (as you don't need to use ',' to separate the command)
But need to refer to another file

task installPackageWithScript(type: Exec) {
    commandLine('sh', './bin/installPackage.sh')
}

2. Refer to Gradle - How to execute command line in doLast and get exit code?, get the exit code from first command to determine whether second command is needed.

No need to refer other file
But less readable and maintainable

task installPackageInline(type: Exec) {
    commandLine('npm', 'list', '-g', 'package')
    doLast {
        if (execResult.exitValue == 0) {
            println "list Success"
        } else {
            println "list Fail, run install"
            exec { commandLine('npm', 'install', '-g', 'package') }
        }
    }
}