fix: Adding exception block for missing env var

vars/slack_notify.groovy

 def call(String status) {
-       try {
-           ansiColor('xterm') {
-               String ANSI_GREEN = "\u001B[32m"
-               String ANSI_NORMAL = "\u001B[0m"
-               String ANSI_BOLD = "\u001B[1m"
-               String ANSI_RED = "\u001B[31m"
-               String ANSI_YELLOW = "\u001B[33m"
-               
-               stage('slack_notify') {
-                   mainDir = sh(returnStdout: true, script: "echo $JOB_NAME").split('/')[-4].trim()
-                   channel_env_name = mainDir.toUpperCase() + "_NOTIFY_SLACK_CHANNEL"
-                   slack_channel = evaluate "$channel_env_name"
-                   if(status == "FAILURE"){
-                     slack_status = 'danger'
-                     build_status = "Failed"
-                  }
-                   else {
-                     slack_status = 'good'
-                     build_status = "Succeded"
-                  }
-                   if (slack_channel != null)
-                   slackSend (
-                         channel: slack_channel,
-                         color: slack_status,
-                          message: "Build ${build_status} - ${env.JOB_NAME} ${env.BUILD_NUMBER} (<${env.BUILD_URL}|Open>)"
-                      )
-                        else if(env.GLOBAL_NOTIFY_SLACK_CHANNEL != null)
-                         slackSend (
+    try {
+        ansiColor('xterm') {
+            String ANSI_GREEN = "\u001B[32m"
+            String ANSI_NORMAL = "\u001B[0m"
+            String ANSI_BOLD = "\u001B[1m"
+            String ANSI_RED = "\u001B[31m"
+            String ANSI_YELLOW = "\u001B[33m"
+
+            stage('slack_notify') {
+                env = sh(returnStdout: true, script: "echo $JOB_NAME").split('/')[-3].trim()
+                channel_env_name = env.toUpperCase() + "_NOTIFY_SLACK_CHANNEL"
+                try {
+                    slack_channel = evaluate "$channel_env_name"
+                }
+                catch (MissingPropertyException ex) {
+                    println ANSI_YELLOW + ANSI_BOLD + "Could not find env specific Slack channel.." + ANSI_NORMAL
+                }
+                if(status == "FAILURE"){
+                    slack_status = 'danger'
+                    build_status = "Failed"
+                }
+                else {
+                    slack_status = 'good'
+                    build_status = "Succeded"
+                }
+                if (slack_channel != null)
+                    slackSend (
+                            channel: slack_channel,
+                            color: slack_status,
+                            message: "Build ${build_status} - ${env.JOB_NAME} ${env.BUILD_NUMBER} (<${env.BUILD_URL}|Open>)"
+                    )
+                else if(env.GLOBAL_NOTIFY_SLACK_CHANNEL != null)
+                    slackSend (
                             channel: "${env.GLOBAL_NOTIFY_SLACK_CHANNEL}",
                             color: slack_status,
                             message: "Build ${build_status} - ${env.JOB_NAME} ${env.BUILD_NUMBER} (<${env.BUILD_URL}|Open>)"
-                       )
-                        else
-                         println ANSI_YELLOW + ANSI_BOLD + "Could not find slack environment variable. Skipping slack notification.." + ANSI_NORMAL
-               }
+                    )
+                else
+                    println ANSI_YELLOW + ANSI_BOLD + "Could not find slack environment variable. Skipping slack notification.." + ANSI_NORMAL
             }
-         }
-      catch (err){
-            throw err
         }
-   }
+    }
+    catch (err){
+        throw err
+    }
+}