The Jenkins automation to read upstream job information is made possible with APIs. For example:

    for (String jobName : jobNames.keySet()) { 

        def imageName = jobNames.get(jobName) 

        def uri = "https://<jenkinsServer>/job/${jobName}/lastSuccessfulBuild/api/json" 

        def buildJson = ["wget", "-qO-", "${uri}"].execute().text 

        def start = buildJson.indexOf('"description":"') 

        def end = buildJson.indexOf('"', start+15) 

        def remoteBuildVersion = "" 

        println("${start}:${end}") 

        if (start != -1 && end != -1 && end > start) { 

            remoteBuildVersion = buildJson.substring(start+15, end) 

        } 

        manifestFileLines.each { line -> 

             if (line.contains("${imageName}:")) { 

                 localBuildVersion  =  line.split(":")[1] 

                 if (remoteBuildVersion != localBuildVersion) { 

                     pattern=remoteBuildVersion 

                     replacement=localBuildVersion 

                     println("replacing ${pattern} with ${replacement} in ${imageName}") 

                     filesToBeModified.eachFileRecurse( 

                            {file -> 

                                  fileText = file.text; 

                                  def backupFile = file.path + ".bak" 

                                  writeFile(file: backupFile, text:  fileText) 

                                  fileText = fileText.replaceAll(pattern, replacement) 

                                  writeFile(file: file.path, text: fileText) 

                            }) 

                 } else { 

                     println("${jobName} build version ${remoteBuildVersion} matches ${localBuildVersion}") 

                 } 

             } 

        } 

    } 

Note the above script is specific to Jenkinsfile and avoids popular groovy syntax even though groovy can be used in Jenkinsfile otherwise we might see errors such as : “Scripts not permitted to use staticMethod org.codehaus.groovy.runtime.DefaultGroovyMethods execute java.util.List. Administrators can decide whether to approve or reject this signature. 

org.jenkinsci.plugins.scriptsecurity.sandbox.RejectedAccessException: Scripts not permitted to use staticMethod org.codehaus.groovy.runtime.DefaultGroovyMethods execute java.util.List”