Jenkinsfile, prebuild script - jenkins

I'm a using the jenkins pipeline. My usecase is that the developer are using a simple *.ini file that is parsed by a python script to add or remove stage within the jenkinsfile whenever they want. I don't want them to manually edit the jenkinsfile because they won't know how it works.
Expected behaviour is:
When a build is triggered I would like to first execute a python script which might write into the jenkinsfile to add/remove stage according to the *.ini file.
As far as I understand, when an event trigger a jenkins build, the first thing it does is opening the jenkinsfile. However I would like to know if it's possible to run some prebuild script before that ?
Thanks
Edit: here's a simple view of run of the pipeline (blue ocean UI)
The ini file might for example remove in the stage Compilation the step Building Plan C by removing the groovy code doing that in the jenkins file

Give an example for reference.
node {
git url: '', branch: '', credentialsId: ''
def parseStr = sh(script: 'python parser.py xxx.ini', returnStdout: true).trim()
// the python parser expect to return a JSON string like:
// {'run_stage1': false, 'run_stage2': true}
def parseObj = readJSON text: parseStr
stage('stage 1') {
if(parseObj.run_stage1) {
echo 'stage1'
...
}
}
stage('stage 1') {
if(parseObj.run_stage2) {
echo 'stage1'
....
}
}
}
Jenkins pipeline had supply apis: readJSON, readYaml, readProperties to read JSON, YAML and Properties files.
If you choose any of them to replace ini file, you can drop the python parser to make your pipeline more simple

Related

Groovy in Jenkins pipeline - create a file with content

I am using Jenkins' shared library and my Jenkins file has a stage like this:
stage('sonarqube') {
when { branch 'master' }
steps {
generateUnitTestsReport()
}
}
I want to keep programmers' repos clean from scripts that create various reports, so my idea is to keep definitions of scripts in a shared library, and then, during step execution, create a file with the content.
For instance (file generateUnitTestsReport.groovy in shared library):
def call(){
def SCRIPT_CONTENT = '''
#!/bin/bash
#SCRIPT CONTENT
'''
sh '''echo''' +SCRIPT_CONTENT+ ''' > ut-report.sh'''
sh 'chmod +x ./ut-report.sh'
}
but it doesn't work like this. I also tried Groovy's new File, but no luck there either. How could this be done (note that this is a Jenkins slave node)?

How to use inject environment variables (Properties File Path) in Jenkins Pipeline

Want to use the below functionality(shown in image link) in Jenkins as code, but i'm failing to do, kindly help me replicate the functionality in the image to groovy script
stage ('Build Instance') {
sh '''
bash ./build.sh -Ddisable-rpm=false
'''
env "/fl/tar/ver.prop"
}
Jenkins GUI usage of Env Inject
Got a simple workaround :
script {
def props = readProperties file: '/fl/tar/ver.prop' //readProperties is a step in Pipeline Utility Steps plugin
env.WEATHER = props.WEATHER //assuming the key name is WEATHER in properties file
}

new File("path/tmp.txt") at Jenkins node

I have a very simple pipeline which works on a master. I was reading a line in a tmp.txt which works on Jenkins (master).
stage ('Stage 1'){
node('master') {
File file1 = new File("env.Workspace/tmp.txt")
def String my_line = file1.readLines().get(0)
…
}
}
I’ve have to move the stage to other one node (slave) and it doesn’t work anymore. If there is a tmp.txt in a workspace of master – pipeline reads it. But I want to read the tmp.txt in a workspace of node, not from master!
stage ('Stage 1'){
node('Agent_1') {
File file1 = new File("env.Workspace/tmp.txt")
def String my_line = file1.readLines().get(0)
…
}
}
I've found an info that:
“File always implies a file path on the current computer”.
What does it mean? It must be possible to read a file from node..
Can anybody help there?
Do not use native Groovy/Java IO functions, but use pipeline steps instead. The reason for this is that the pipeline code itself is always executed on the master!
The correct (pseudo) code, using the readFile step, would be like:
stage ('Stage 1'){
node('Agent_1') {
def String my_line = readFile("tmp.txt")
…
}
}

Jenkins: "Execute system groovy script" in a pipeline step (SCM committed)

Is there a way to use the Jenkins "Execute system groovy script" step from a pipeline file which is SCM commited ?
If yes, how would I access the predefined variables (like build) in it ?
If no, would I be able to replicate the functionality otherwise, using for example the Shared Library Plugin ?
Thanks !
You can put groovy code in a pipeline in a (always-source-controlled) Jenkinsfile, like this:
pipeline {
agent { label 'docker' }
stages {
stage ('build') {
steps {
script {
// i used a script block because you can jam arbitrary groovy in here
// without being constrained by the declarative Jenkinsfile DSL
def awesomeVar = 'so_true'
print "look at this: ${awesomeVar}"
// accessing a predefined variable:
echo "currentBuild.number: ${currentBuild.number}"
}
}
}
}
}
Produces console log:
[Pipeline] echo
look at this: so_true
[Pipeline] echo
currentBuild.number: 84
Click on the "Pipeline Syntax" link in the left navigation of any of pipeline job to get a bunch of examples of things you can access in the "Global Variables Reference."

Load file with environment variables Jenkins Pipeline

I am doing a simple pipeline:
Build -> Staging -> Production
I need different environment variables for staging and production, so i am trying to source variables.
sh 'source $JENKINS_HOME/.envvars/stacktest-staging.sh'
But it returns Not found
[Stack Test] Running shell script
+ source /var/jenkins_home/.envvars/stacktest-staging.sh
/var/jenkins_home/workspace/Stack Test#tmp/durable-bcbe1515/script.sh: 2: /var/jenkins_home/workspace/Stack Test#tmp/durable-bcbe1515/script.sh: source: not found
The path is right, because i run the same command when i log via ssh, and it works fine.
Here is the pipeline idea:
node {
stage name: 'Build'
// git and gradle build OK
echo 'My build stage'
stage name: 'Staging'
sh 'source $JENKINS_HOME/.envvars/stacktest-staging.sh' // PROBLEM HERE
echo '$DB_URL' // Expects http://production_url/my_db
sh 'gradle flywayMigrate' // To staging
input message: "Does Staging server look good?"
stage name: 'Production'
sh 'source $JENKINS_HOME/.envvars/stacktest-production.sh'
echo '$DB_URL' // Expects http://production_url/my_db
sh 'gradle flywayMigrate' // To production
sh './deploy.sh'
}
What should i do?
I was thinking about not using pipeline (but i will not be able to use my Jenkinsfile).
Or make different jobs for staging and production, using EnvInject Plugin (But i lose my stage view)
Or make withEnv (but the code gets big, because today i am working with 12 env vars)
One way you could load environment variables from a file is to load a Groovy file.
For example:
Let's say you have a groovy file in '$JENKINS_HOME/.envvars' called 'stacktest-staging.groovy'.
Inside this file, you define 2 environment variables you want to load
env.DB_URL="hello"
env.DB_URL2="hello2"
You can then load this in using
load "$JENKINS_HOME/.envvars/stacktest-staging.groovy"
Then you can use them in subsequent echo/shell steps.
For example, here is a short pipeline script:
node {
load "$JENKINS_HOME/.envvars/stacktest-staging.groovy"
echo "${env.DB_URL}"
echo "${env.DB_URL2}"
}
From the comments to the accepted answer
Don't use global 'env' but use 'withEnv' construct, eg see:
issue #9: don't set env vars with global env in top 10 best practices jenkins pipeline plugin
In the following example: VAR1 is a plain java string (no groovy variable expansion), VAR2 is a groovy string (so variable 'someGroovyVar' is expanded).
The passed script is a plain java string, so $VAR1 and $VAR2 are passed literally to the shell, and the echo's are accessing environment variables VAR1 and VAR2.
stage('build') {
def someGroovyVar = 'Hello world'
withEnv(['VAR1=VALUE ONE',
"VAR2=${someGroovyVar}"
]) {
def result = sh(script: 'echo $VAR1; echo $VAR2', returnStdout: true)
echo result
}
}
For secrets / passwords you can use credentials binding plugin
Example:
NOTE: CREDENTIALS_ID1 is a registered username/password secret on the Jenkins settings.
stage('Push') {
withCredentials([usernamePassword(
credentialsId: 'CREDENTIALS_ID1',
passwordVariable: 'PASSWORD',
usernameVariable: 'USER')]) {
echo "User name: $USER"
echo "Password: $PASSWORD"
}
}
The jenkisn console log output hides the real values:
[Pipeline] echo
User name: ****
[Pipeline] echo
Password: ****
Jenkins and credentials is a big issue, probably see: credentials plugin
For completeness: Most of the time, we need the secrets in environment variables, as we use them from shell scripts, so we combine the withCredentials and withEnv like follows:
stage('Push') {
withCredentials([usernamePassword(
credentialsId: 'CREDENTIALS_ID1',
passwordVariable: 'PASSWORD',
usernameVariable: 'USER')]) {
withEnv(["ENV_USERNAME=${USER}",
"ENV_PASSWORD=${PASSWORD}"
]) {
def result = sh(script: 'echo $ENV_USERNAME', returnStdout: true)
echo result
}
}
}
Another way to resolve this install 'Pipeline Utility Steps' plugin that provides us readProperties method ( for reference please go to the link https://jenkins.io/doc/pipeline/steps/pipeline-utility-steps/#pipeline-utility-steps)
Here in the example we can see that they are storing the keys into an array and using the keys to retrieve the value.
But in that case the in production the problem will be like if we add any variable later into property file that variable needs to be added into the array of Jenkins file as well.
To get rid of this tight coupling, we can write code in such a way so that the Jenkins build environment can get information automatically about all the existing keys which presents currently in the Property file. Here is an example for the reference
def loadEnvironmentVariables(path){
def props = readProperties file: path
keys= props.keySet()
for(key in keys) {
value = props["${key}"]
env."${key}" = "${value}"
}
}
And the client code looks like
path = '\\ABS_Output\\EnvVars\\pic_env_vars.properties'
loadEnvironmentVariables(path)
With declarative pipeline, you can do it in one line ( change path by your value):
script {
readProperties(file: path).each {key, value -> env[key] = value }
}
Using withEnv() to pass environment variables from file splitted by new line and casted to List:
writeFile file: 'version.txt', text: 'version=6.22.0'
withEnv(readFile('version.txt').split('\n') as List) {
sh "echo ${version}"
}
If you are using Jenkins 2.0 you can load the property file (which consists of all required Environment variables along with their corresponding values) and read all the environment variables listed there automatically and inject it into the Jenkins provided env entity.
Here is a method which performs the above stated action.
def loadProperties(path) {
properties = new Properties()
File propertiesFile = new File(path)
properties.load(propertiesFile.newDataInputStream())
Set<Object> keys = properties.keySet();
for(Object k:keys){
String key = (String)k;
String value =(String) properties.getProperty(key)
env."${key}" = "${value}"
}
}
To call this method we need to pass the path of property file as a string variable For example, in our Jenkins file using groovy script we can call like
path = "${workspace}/pic_env_vars.properties"
loadProperties(path)
Please ask me if you have any doubt
Here is a complete example of externalizing environment variables and loading them in Jenkins pipeline execution. The pipeline is written in a declarative style.
stage('Reading environment variable defined in groovy file') {
steps {
script {
load "./pipeline/basics/extenvvariable/env.groovy"
echo "${env.env_var1}"
echo "${env.env_var2}"
}
}
}
Complete code example:
https://github.com/dhruv-bansal/jenkins-pipeline-exploration/blob/master/pipeline/basics/extenvvariable/Jenkinsfile
Where variables are loaded from a groovy file placed with the pipeline code only.
https://github.com/dhruv-bansal/jenkins-pipeline-exploration/blob/master/pipeline/basics/extenvvariable/env.groovy
This pattern comes very handy when you are creating a generic pipeline that could be used across teams.
You can externalize the dependent variable in such groovy file and each team can define their values according to their ecosystem.
Another solution is to use a custom method without allowing extra permissions such as for new Properties() which leads to this error before allowing:
org.jenkinsci.plugins.scriptsecurity.sandbox.RejectedAccessException: Scripts not permitted to use new java.util.Properties
or adding extra plugin methods such as readProperties.
here is a method which reads a simple file named env_vars in this format:
FOO=bar
FOO2=bar
pipeline {
<... skipped lines ...>
script {
loadEnvironmentVariablesFromFile("env_vars")
echo "show time! ${BAR} ${BAR2}"
}
<... skipped lines ...>
}
private void loadEnvironmentVariablesFromFile(String path) {
def file = readFile(path)
file.split('\n').each { envLine ->
def (key, value) = envLine.tokenize('=')
env."${key}" = "${value}"
}
}

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