Create JSON strings from Groovy variables in Jenkins Pipeline

JSON is a format that uses human-readable text to transmit data objects consisting of attribute–value pairs and array data types.So, in general json is a formatted text.

In groovy json object is just a sequence of maps/arrays.

parsing json using JsonSlurperClassic

//use JsonSlurperClassic because it produces HashMap that could be serialized by pipelineimport groovy.json.JsonSlurperClassicnode{    def json = readFile(file:'message2.json')    def data = new JsonSlurperClassic().parseText(json)    echo "color: ${data.attachments[0].color}"}

parsing json using pipeline

node{    def data = readJSON file:'message2.json'    echo "color: ${data.attachments[0].color}"}

building json from code and write it to file

import groovy.json.JsonOutputnode{    //to create json declare a sequence of maps/arrays in groovy    //here is the data according to your sample    def data = [        attachments:[            [                fallback: "New open task [Urgent]: <http://url_to_task|Test out Slack message attachments>",                pretext : "New open task [Urgent]: <http://url_to_task|Test out Slack message attachments>",                color   : "#D00000",                fields  :[                    [                        title: "Notes",                        value: "This is much easier than I thought it would be.",                        short: false                    ]                ]            ]        ]    ]    //two alternatives to write    //native pipeline step:    writeJSON(file: 'message1.json', json: data)    //but if writeJSON not supported by your version:    //convert maps/arrays to json formatted string    def json = JsonOutput.toJson(data)    //if you need pretty print (multiline) json    json = JsonOutput.prettyPrint(json)    //put string into the file:    writeFile(file:'message2.json', text: json)}

Found this question while I was trying to do something (I believed) should be simple to do, but wasn't addressed by the other answer. If you already have the JSON loaded as a string inside a variable, how do you convert it to a native object? Obviously you could do new JsonSlurperClassic().parseText(json) as the other answer suggests, but there is a native way in Jenkins to do this:

node () {  def myJson = '{"version":"1.0.0"}';  def myObject = readJSON text: myJson;  echo myObject.version;}

Hope this helps someone.

Edit: As explained in the comments "native" isn't quite accurate.

If you are stucked on an installation using sandboxes and Jenkins Script Security plugin with no possibility to add whitelisted classes/methods, the only way I found is the following :

def slackSendOnRestrictedContext(params) {    if (params.attachments != null) {        /* Soooo ugly but no other choice with restrictions of           Jenkins Script Pipeline Security plugin ^^ */        def paramsAsJson = JsonOutput.toJson(params)        def paramsAsJsonFromReadJson = readJSON text: paramsAsJson        params.attachments = paramsAsJsonFromReadJson.attachments.toString()    }    slackSend (params)}