I've struggled with this for a while but finally made it!
Main goal was to read a list of docker images tags from a private docker registry, each time a Jenkins job is executed.
Decided to use a Active Choice plug-in.
This plug-in provides several additional Jenkins parameter types that can be rendered as user interface (UI) controls in job forms. It supports using system environment variables, global node properties, and you also have at least the Jenkins project in the Groovy context for Freestyle jobs.
For my use case Active Choice Reactive Parameter will be a best fit as it dynamically generate value options for a build parameter using a Groovy script. In addition it can be dynamically updated when the value of other job UI control change.
Requirements
Project type
According to the plugin description it requires our job will be a freestyle job.
Parameters to define
Lets assume the following params will be needed:
- Service - our selected service
- Tag - list of tags from registry
- Environment - place where its gonna be deployed
Docker credentials
Because registry is private and I don't want to keep credentials in any kind of scripts or jobs my idea is to use credentials store in Jenkins. Adding my docker username and password:
Now I will be able to use it inside a script just by using a credential ID.
Creating the Job
On the beginning let's tick This project is parameterized and start adding params.
From the UI side it will look like this:
1. Service parameter
First parameter will allow to select the service. Based on this choice we will be getting a list of docker image tags in the next parameter.
This should be a Active Choices Parameter as we will use the name in the next one.
So the name for the param will be Service and we will use a Groovy script to return a list of values, like this:
return ['web-service', 'proxy-service', 'backend-service']Fallback choice is something that can be skipped as its not possible that something will go wrong while returning a list :)
Choice type I'm setting to Single Select.
At the end it should look like this:
2. Tag parameter
Second parameter will be the tag that we want to choose. Its slightly more complicated to get the data form a remote api with authentication so there will be move groovy involved.
This time we adding Active Choices Reactive Parameter
Name of this one is set to Tag and we will use another Groovy script like before to return a list of image tags:
import groovy.json.JsonSlurperClassic
import jenkins.model.Jenkins
image = imageName(Service)
token = getAuthTokenDockerHub()
tags = getTagFromDockerHub(image, token)
return tags
def getTagFromDockerHub(imgName, authToken) {
def url = new URL("https://hub.docker.com/v2/repositories/${imgName}/tags?page=1&page_size=50")
def parsedJSON = parseJSON(url.getText(requestProperties:["Authorization":"JWT ${authToken}"]))
def regexp = "^\\d{1,2}.\\d{1,2}\$"
parsedJSON.results.findResults {
it.name =~ /$regexp/ ? "${it.name}".toString() : null
}
}
def getAuthTokenDockerHub() {
def creds = com.cloudbees.plugins.credentials.CredentialsProvider.lookupCredentials(
com.cloudbees.plugins.credentials.common.StandardUsernameCredentials.class,
Jenkins.instance,
null,
null)
for (c in creds) {
if (c.id == "dockerhub_credentials") {
user = c.username
pass = c.password
}
}
def url = new URL("https://hub.docker.com/v2/users/login/")
def conn = url.openConnection()
conn.setRequestMethod("POST")
conn.setRequestProperty("Content-Type", "application/json")
conn.doOutput = true
def authString = "{\"username\": \"${user}\", \"password\": \"${pass}\"}"
def writer = new OutputStreamWriter(conn.outputStream)
writer.write(authString)
writer.flush()
writer.close()
conn.connect()
def result = parseJSON(conn.content.text)
return result.token
}
def parseJSON(json) {
return new groovy.json.JsonSlurperClassic().parseText(json)
}
def imageName(name){
return "bartekj/${name}".toString()
}
Another thing that need to be done before the above code will work is to define a Referenced parameters as the image variable depends on it.
I will not get into details that much as this script is pretty straight forward.
It puts an image name together based on Service parameter, obtaining a token from dockerhub using Jenkins credentials ID and parse json output with selected regex returning a list of docker image tags.
Same as before setting up choice type to Single Select.
3. Environment parameter
Last element that will be needed is a simple Choice parameter that together with previous params will be used inside Jenkinsfile after the job will be executed.
Name: Environment and choices (one per line): test stage prod.
Should look like this:
Putting everything together
Putting everything together there is one case to remember (depending on your Jenkins security config). We are using groovy scripts in a job so after first run go to Manage Jenkins >> In-process Script Approval and approve the code that was used here (possibly scripts and fallback).
When everything is ready it should look like this:
Extra: job DSL definition
For those who use here is a snippet for DSL. (without scm definition and other stuff)
job('microservices-deploy') {
parameters {
activeChoiceParam('Service') {
description('Select service you wan to deploy')
choiceType('SINGLE_SELECT')
groovyScript {
script('return ['web-service', 'proxy-service', 'backend-service']')
fallbackScript('"fallback choice"')
}
}
activeChoiceReactiveParam('Tag') {
description('Select tag from dockerhub')
choiceType('SINGLE_SELECT')
groovyScript {
script('''
import groovy.json.JsonSlurperClassic
import jenkins.model.Jenkins
image = imageName(Service)
token = getAuthTokenDockerHub()
tags = getTagFromDockerHub(image, token)
return tags
def getTagFromDockerHub(imgName, authToken) {
def url = new URL("https://hub.docker.com/v2/repositories/${imgName}/tags?page=1&page_size=50")
def parsedJSON = parseJSON(url.getText(requestProperties:["Authorization":"JWT ${authToken}"]))
def regexp = "^\\d{1,2}.\\d{1,2}\$"
parsedJSON.results.findResults {
it.name =~ /$regexp/ ? "${it.name}".toString() : null
}
}
def getAuthTokenDockerHub() {
def creds = com.cloudbees.plugins.credentials.CredentialsProvider.lookupCredentials(
com.cloudbees.plugins.credentials.common.StandardUsernameCredentials.class,
Jenkins.instance,
null,
null)
for (c in creds) {
if (c.id == "dockerhub_credentials") {
user = c.username
pass = c.password
}
}
def url = new URL("https://hub.docker.com/v2/users/login/")
def conn = url.openConnection()
conn.setRequestMethod("POST")
conn.setRequestProperty("Content-Type", "application/json")
conn.doOutput = true
def authString = "{\"username\": \"${user}\", \"password\": \"${pass}\"}"
def writer = new OutputStreamWriter(conn.outputStream)
writer.write(authString)
writer.flush()
writer.close()
conn.connect()
def result = parseJSON(conn.content.text)
return result.token
}
def parseJSON(json) {
return new groovy.json.JsonSlurperClassic().parseText(json)
}
def imageName(name){
return "bartekj/${name}".toString()
}
''')
fallbackScript('"fallback choice"')
}
referencedParameter('Service')
}
choiceParam('Environment', ['test', 'stage', 'prod'], 'Select environment')
}
}
Enjoy!