minimizing Downtime

ee/cli/plugins/stack.py

@@ -1699,15 +1699,21 @@ class EEStackController(CementBaseController):
                                           'operation.')
                         ee_prompt = input("Type \"YES\" or \"yes\" to continue [n]: ")
                         if ee_prompt == 'YES' or ee_prompt == 'yes':
-                            EEService.stop_service(self, 'nginx')
-                            Log.debug(self, "Removing apt_packages variable of Nginx")
-                            Log.info(self, "Removing packages, please wait...")
-                            EEAptGet.remove(self, EEVariables.ee_nginx_dev)
-                            EEAptGet.auto_remove(self)
-                            Log.info(self, "Removing repository for NGINX MAINLINE,")
+                            Log.info(self,"Initializing... Please Wait")
                             EERepo.remove(self, repo_url=EEVariables.ee_nginx_dev_repo)
-                            Log.info(self, "Successfully removed packages")
-                            apt_packages = apt_packages + EEVariables.ee_nginx
+                            if EEAptGet.download_only(self,EEVariables.ee_nginx,EEVariables.ee_nginx_repo,EEVariables.ee_nginx_key):
+                                EEService.stop_service(self, 'nginx')
+                                Log.debug(self, "Removing apt_packages variable of NGINX")
+                                Log.info(self, "Removing packages, please wait...")
+                                EEAptGet.remove(self, EEVariables.ee_nginx_dev)
+                                EEAptGet.auto_remove(self)
+                                Log.info(self, "Removing repository for NGINX MAINLINE,")
+                                Log.info(self, "Successfully removed packages")
+                                apt_packages = apt_packages + EEVariables.ee_nginx
+                            else:
+                                #revert the changes
+                                EERepo.add(self, repo_url=EEVariables.ee_nginx_dev_repo)
+                                Log.error(self,"Skipped installing NGINX Stable")
 
             if self.app.pargs.nginxmainline:
                 if EEVariables.ee_nginx_dev_repo == None:
@@ -1731,13 +1737,17 @@ class EEStackController(CementBaseController):
                                           'operation.')
                         ee_prompt = input("Type \"YES\" or \"yes\" to continue [n]: ")
                         if ee_prompt == 'YES' or ee_prompt == 'yes':
-                            EEService.stop_service(self, 'nginx')
-                            Log.debug(self, "Removing apt_packages variable of Nginx")
-                            Log.info(self, "Removing packages, please wait...")
-                            EEAptGet.remove(self, EEVariables.ee_nginx)
-                            EEAptGet.auto_remove(self)
-                            Log.info(self, "Successfully removed packages")
-                            apt_packages = apt_packages + EEVariables.ee_nginx_dev
+                            Log.info(self,"Initializing... Please Wait")
+                            if EEAptGet.download_only(self,EEVariables.ee_nginx_dev,EEVariables.ee_nginx_dev_repo,EEVariables.ee_nginx_key):
+                                EEService.stop_service(self, 'nginx')
+                                Log.debug(self, "Removing apt_packages variable of Nginx")
+                                Log.info(self, "Removing packages, please wait...")
+                                EEAptGet.remove(self, EEVariables.ee_nginx)
+                                EEAptGet.auto_remove(self)
+                                Log.info(self, "Successfully removed packages")
+                                apt_packages = apt_packages + EEVariables.ee_nginx_dev
+                            else:
+                                Log.error(self,"Skipped installing NGINX Mainline")
 
             if self.app.pargs.php:
                 Log.debug(self, "Setting apt_packages variable for PHP")

ee/core/aptget.py

@@ -195,3 +195,36 @@ class EEAptGet():
             return True
         # apt_cache.close()
         return False
+
+    def download_only(self,package_name,repo_url=None,repo_key=None):
+        """
+        Similar to `apt-get install  --download-only`
+        """
+        try:
+            with open('/var/log/ee/ee.log', 'a') as f:
+                if repo_url is not None:
+                    EERepo.add(self, repo_url=repo_url)
+                if repo_key is not None:
+                    EERepo.add_key(self, repo_key)
+                proc = subprocess.Popen("DEBIAN_FRONTEND=noninteractive "
+                                        "apt-get install -o "
+                                        "Dpkg::Options::=\"--force-confdef\""
+                                        " -o "
+                                        "Dpkg::Options::=\"--force-confold\""
+                                        " -y  --download-only {0}"
+                                        .format(package_name), shell=True,
+                                        stdin=None, stdout=f, stderr=f,
+                                        executable="/bin/bash")
+                proc.wait()
+
+            if proc.returncode == 0:
+                return True
+            else:
+                Log.error(self,"Error in fetching dpkg package.\nReverting changes ..",False)
+                if repo_url is not None:
+                    EERepo.remove(self, repo_url=repo_url)
+                return False
+        except Exception as e:
+            Log.error(self, "Error while downloading packages, "
+                      "apt-get exited with error")
+