dnf: Give advanced users some control over plugins

Let's add some environment variables to control plugins for cases
where users have some dnf plugin they can't touch on their host system
which doesn't behave properly in mkosi-sandbox and which they can't
remove themselves.

Author: daandemeyer

mkosi/installer/dnf.py

@@ -169,6 +169,11 @@ def cmd(
             "--setopt=persistdir=/buildroot/var/lib/dnf",
         ]
 
+        if plugins := context.config.environment.get("MKOSI_DNF_DISABLE_PLUGINS"):
+            cmdline += [f"--disableplugin={plugins}"]
+        if plugins := context.config.environment.get("MKOSI_DNF_ENABLE_PLUGINS"):
+            cmdline += [f"--enableplugin={plugins}"]
+
         if ARG_DEBUG.get():
             cmdline += ["--setopt=debuglevel=10"]
 

mkosi/resources/man/mkosi.1.md

@@ -3127,6 +3127,12 @@ repository.
 * `$MKOSI_DNF` can be used to override the executable used as **dnf**.
   This is particularly useful to select between **dnf** and **dnf5**.
 
+* `$MKOSI_DNF_DISABLE_PLUGINS` can be used to disable dnf plugins. The value
+  is forwarded to dnf's `--disableplugin=` option.
+
+* `$MKOSI_DNF_ENABLE_PLUGINS` can be used to enable dnf plugins. The value
+  is forwarded to dnf's `--enableplugin=` option.
+
 * `$EPEL_MIRROR` can be used to override the default mirror location
   used for the epel repositories when `Mirror=` is used. By default
   **mkosi** looks for the epel repositories in the `fedora` subdirectory of