Groovy - Define variable where the variable name is passed by another variable

Question

I want define a variable in groovy with where the variable name is passed by another variable.

Something like.

def runExtFunc(varName){
    def varName  // => def abc
    varName = load 'someFile.groovy'   // abc = load 'someFile.groovy'

    varName."$varName"() // -> abc.abc() (run function defined in File)
}

    [...]
runExtFunc('abc')  // -> abc.abc() (Function abc defined in File)
    [...]
runExtFunc('xyz')  // -> xyz.xyz() (Function xyz defined in File)
    [...]

Sadly def varName defines the variable varName and not abc. When I call runExtFunc twice an error occoures bacause varName is already defined.

I also tried

def runExtFunc(varName){
    def "${varName}"  // => def abc
       [...]
    "${varName}" =  load 'someFile.groovy'
       [...]
}

which doesn't work either.

Any suggestions?

Answer 1

This is the wrong approach. Normally you would use List, Map or Set data structures, which allow you to save a collection and access specific elements in the collection.

List allows you to hold specific values (unique or non-unique). Set allows you to hold specific values (all unique). Map allows you to have Key, Value pairs (Key must be unique) .

Read more here groovy list, groovy map

Answer 2

Try this (if I understand you correctly):

def dummyFunc(varName) {
  new GroovyShell(this.binding).evaluate("${varName}")
}

dummyFunc('abc')

abc = "Hello there"
println abc

Prints

Hello there

Answer 3

See here https://godless-internets.org/2020/02/14/extracting-jenkins-credentials-for-use-in-another-place/

secret_var="SECRET_VALUE_${secret_index}" aws ssm put-parameter --name ${param_arn} --type "SecureString" --value ${!secret_var} --region us-east-2 --overwrite

Answer 4

I'm entering here a code sample we've done.

Please, feel free to comment.

http://groovy-lang.org/syntax.html https://godless-internets.org/2020/02/14/extracting-jenkins-credentials-for-use-in-another-place/

def int fileContentReplaceDynamic(String filePathVar, String envTail = "", 
String [] keysToIgnore = new String[0]){

def filePath = readFile filePathVar
def lines = filePath.readLines()

//def regex = ~/\b__\w*\b/
String regex = "__(.*?)__"
ArrayList credentialsList = new ArrayList();
ArrayList<String> keysToIgnoreList = new ArrayList<String>(Arrays.asList(keysToIgnore));

for (line in lines){
    Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE)
    Matcher matcher = pattern.matcher(line)

    while (matcher.find()){
        String credKeyName = matcher.group().replaceAll("__","")
        if ((! credentialsList.contains(credKeyName)) && 
            (! keysToIgnoreList.contains(credKeyName))) {
            credentialsList.add(credKeyName)
        } else {
            log.info("Credencial ignorada o ya incluida: ${credKeyName}")
        }
    }       
}


if(credentialsList.size() <= 0){
    log.info("No hay variables para aplicar transformada")
    return 0
}

log.info("Numero de credenciales encontradas a sustituir: " + credentialsList.size())
String credentialsListString = String.join(", ", credentialsList);
log.info("Credenciales: " + credentialsListString)

def credsRequest = null
for(def credKeyName in credentialsList){
    // Retrieve the values of the variables by environment tail name.
    String credKeyNameByEnv = "${credKeyName}";
    if ((envTail != null) && (! envTail.trim().isEmpty())) {
        credKeyNameByEnv = credKeyNameByEnv + "-" + envTail.trim().toUpperCase();
    }
    
    // Now define the name of the variable we'll use
    // List<org.jenkinsci.plugins.credentialsbinding.MultiBinding>
    // Tip: java.lang.ClassCastException: 
    // org.jenkinsci.plugins.credentialsbinding.impl.BindingStep.bindings 
    // expects class org.jenkinsci.plugins.credentialsbinding.MultiBinding
    String varName = "var_${credKeyNameByEnv}"
    if (credsRequest == null) {
        // Initialize
        credsRequest = [string(credentialsId: "${credKeyNameByEnv}", variable: "${varName}")]
    } else {
        // Add element
        credsRequest << string(credentialsId: "${credKeyNameByEnv}", variable: "${varName}")
    }
}

int credsProcessed = 0
def passwordsRequest = null
StringBuilder sedReplacements = new StringBuilder();

// Now ask jenkins to fill in all variables with values
withCredentials(credsRequest) {
    for(def credKeyName in credentialsList){
        String credKeyVar = "var_${credKeyName}"
        log.info("Replacing value for credential ${credKeyName} stored in ${credKeyVar}")
        
        String credKeyValueIn = "${!credKeyVar}"
        String credKeyValue = null;
        if ("empty_string_value".equals(credKeyValueIn.trim())) {
            credKeyValue = "";
        } else {
            credKeyValue = credKeyValueIn.replaceAll(/(!|"|@|#|\$|%|&|\/|\(|\)|=|\?)/, /\\$0/)
        }
        
        if (passwordsRequest == null) {
            // Initialize
            passwordsRequest = [[password: "${credKeyValue}" ]]
        } else {
            // Add element
            passwordsRequest << [password: "${credKeyValue}" ]
        }
        
        sedReplacements.append("s/__${credKeyName}__/${credKeyValue}/; ")
        
        credsProcessed++
    }
}

wrap([$class: "MaskPasswordsBuildWrapper", varPasswordPairs: passwordsRequest ]){
    
    String sedReplacementsString = sedReplacements.toString().trim();
    if (sedReplacementsString.endsWith(";")) {
        sedReplacementsString = sedReplacementsString.substring(0, sedReplacementsString.length() -1);
        sedReplacementsString = sedReplacementsString + "g;"
    }
    
    sh """sed -i "${sedReplacementsString}" ${filePathVar}"""
}

log.info("Finaliza la transformada. Transformados: ${credsProcessed}/${credentialsList.size()} ")

if (credsProcessed != credentialsList.size()) {
    log.info("Hay credenciales que no se han podido encontrar en el vault de Jenkins.")
    log.info("Si estas guardando cadenas vacias en credenciales, guarda en su lugar el valor 'empty_string_value'.");
    return -1
}
return 0;
}