Gradle: Force Custom Task to always run (no cache)

Question

I wrote up a custom Gradle task to handle some dependency resolution on the file system where the paths are configurable. I want tasks of this type to always run. It seems though they only run once, I'm guessing because the inputs never seem to change.

I am aware of using configurations { resolutionStrategy.cacheChangingModulesFor 0, 'seconds' } to effectively disable the cache, but I only want it to apply to very specific tasks. Also am aware of --rerun-tasks command line prompt, which is also similar. Neither feel like the best solution, there must be a way to set this up properly in the custom task definition.

Follows is my current implementation. I also had a version prior where the first 3 def String statements were instead @Input annotated String declarations.

class ResolveProjectArchiveDependency extends DefaultTask {     def String archiveFilename = ""     def String relativeArchivePath = ""     def String dependencyScope = ""      @OutputFile     File outputFile      @TaskAction     void resolveArtifact() {         def arcFile = project.file("dependencies/"+dependencyScope+"/"+archiveFilename)         def newArcFile = ""          if(project.hasProperty('environmentSeparated') && project.hasProperty('separatedDependencyRoot')){             println "Properties set denoting the prerelease environment is separated"             newArcFile = project.file(project.ext.separatedDependencyRoot+relativeArchivePath+archiveFilename)         }   else {             newArcFile = project.file('../../'+relativeArchivePath+archiveFilename)         }          if(!newArcFile.isFile()){             println "Warn: Could not find the latest copy of " + archiveFilename + ".."              if(!arcFile.isFile()) {                 println "Error: No version of " + archiveFilename + " can be found"                 throw new StopExecutionException(archiveFilename +" missing")             }         }          if(!arcFile.isFile()) {             println archiveFilename + " jar not in dependencies, pulling from archives"         } else {             println archiveFilename + " jar in dependencies. Checking for staleness"              def oldHash = generateMD5(new File(arcFile.path))             def newHash = generateMD5(new File(newArcFile.path))              if(newHash.equals(oldHash)) {                 println "Hashes for the jars match. Not pulling in a copy"                 return             }         }          //Copy the archive         project.copy {             println "Copying " + archiveFilename             from newArcFile             into "dependencies/"+dependencyScope         }     }      def generateMD5(final file) {        MessageDigest digest = MessageDigest.getInstance("MD5")        file.withInputStream(){is->        byte[] buffer = new byte[8192]        int read = 0           while( (read = is.read(buffer)) > 0) {                  digest.update(buffer, 0, read);              }          }        byte[] md5sum = digest.digest()        BigInteger bigInt = new BigInteger(1, md5sum)        return bigInt.toString(16)     } } 

Here's an example of usage of the task:

task handleManagementArchive (type: com.moremagic.ResolveProjectArchiveDependency) {     archiveFilename = 'management.jar'     relativeArchivePath = 'management/dist/'     dependencyScope = 'compile/archive'     outputFile = file('dependencies/'+dependencyScope+'/'+archiveFilename) } 

Answer 1

You can achieve this by setting outputs.upToDateWhen { false } on the task.

This can be performed in your build.gradle file:

handleManagementArchive.outputs.upToDateWhen { false } 

It can also be done in the constructor of your custom task.

ResolveProjectArchiveDependency() {     outputs.upToDateWhen { false } }