feat: allow passing values to writePipelineEnv (#5261)

vars/writePipelineEnv.groovy

@@ -6,20 +6,27 @@ import groovy.transform.Field
 void call(Map parameters = [:]) {
     final script = checkScript(this, parameters) ?: this
     String piperGoPath = parameters?.piperGoPath ?: './piper'
+    String command = "${piperGoPath} writePipelineEnv"
+
+    if (parameters.value) {
+        command += " --value '${parameters.value}'"
+    }
     Map cpe = script?.commonPipelineEnvironment?.getCPEMap(script)
-    if (cpe == null) {
+    if (cpe == null) return
+
+    def jsonMap = groovy.json.JsonOutput.toJson(cpe)
+    if (!jsonMap) {
+        script.echo("can't write pipelineEnvironment: empty environment")
         return
     }
+    withEnv(["PIPER_pipelineEnv=${jsonMap}"]) {
+        executeCommand(script, command, parameters?.verbose)
+    }
+}
 
-    def jsonMap = groovy.json.JsonOutput.toJson(cpe)
-    if (piperGoPath && jsonMap) {
-        withEnv(["PIPER_pipelineEnv=${jsonMap}"]) {
-            def output = script.sh(returnStdout: true, script: "${piperGoPath} writePipelineEnv")
-            if (parameters?.verbose) {
-                script.echo("wrote commonPipelineEnvironment: ${output}")
-            }
-        }
-    } else {
-        script.echo("can't write pipelineEnvironment: piperGoPath: ${piperGoPath} piperEnvironment ${jsonMap}")
+private void executeCommand(script, String command, boolean verbose) {
+    def output = script.sh(returnStdout: true, script: command)
+    if (verbose) {
+        script.echo("wrote commonPipelineEnvironment: ${output}")
     }
 }