Check for obvious conflict with already running apt/dpkg commands when running yunohost upgrade

locales/en.json

@@ -157,6 +157,7 @@
     "diagnosis_monitor_system_error": "Can't monitor system: {error}",
     "diagnosis_no_apps": "No installed application",
     "dpkg_is_broken": "You cannot do this right now because dpkg/apt (the system package managers) seems to be in a broken state... You can try to solve this issue by connecting through SSH and running `sudo dpkg --configure -a`.",
+    "dpkg_lock_not_available": "This command can't be ran right now because another program seems to be using the lock of dpkg (the system package manager)",
     "dnsmasq_isnt_installed": "dnsmasq does not seem to be installed, please run 'apt-get remove bind9 && apt-get install dnsmasq'",
     "domain_cannot_remove_main": "Cannot remove main domain. Set a new main domain first",
     "domain_cert_gen_failed": "Unable to generate certificate",

src/yunohost/tools.py

@@ -553,6 +553,10 @@ def tools_upgrade(operation_logger, apps=None, system=False):
     if packages.dpkg_is_broken():
         raise YunohostError("dpkg_is_broken")
 
+    # Check for obvious conflict with other dpkg/apt commands already running in parallel
+    if not packages.dpkg_lock_available():
+        raise YunohostError("dpkg_lock_not_available")
+
     if system is not False and apps is not None:
         raise YunohostError("tools_upgrade_cant_both")
 

src/yunohost/utils/packages.py

@@ -482,6 +482,8 @@ def dpkg_is_broken():
     return any(re.match("^[0-9]+$", f)
                for f in os.listdir("/var/lib/dpkg/updates/"))
 
+def dpkg_lock_available():
+    return os.system("lsof /var/lib/dpkg/lock >/dev/null") != 0
 
 def _list_upgradable_apt_packages():