[elbe-devel] [PATCH] elbepack: initvm: print better errors if the initvm is missing

[Thomas Weißschuh]

Most "elbe initvm" subcommands require the initvm to exist.
Currently the code does not validate this and in case of an error prints a
fairly useless exception.

Add a dedicated exception with a clear message.

Reported-by: Javier Fernandez Pastrana <jfpastrana at linutronix.de>
Signed-off-by: Thomas Weißschuh <thomas.weissschuh at linutronix.de>
---
 elbepack/initvm.py                               | 9 ++++++---
 newsfragments/+missing-libvirt-domain.bugfix.rst | 1 +
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/elbepack/initvm.py b/elbepack/initvm.py
index e5ec0c299ffa3b9e6bb32ae62c223eb67d639656..52e3e118a6b03ccd2785f0297e1313cf17bd63df 100644
--- a/elbepack/initvm.py
+++ b/elbepack/initvm.py
@@ -158,13 +158,16 @@ class LibvirtInitVM(_InitVM):
                 # In case we get here, the exception is unknown, and we want to see it
                 raise
 
-    def _get_domain(self):
+    def _get_domain(self, allow_missing=False):
         doms = self._conn.listAllDomains()
 
         for d in doms:
             if d.name() == self._domain:
                 return d
 
+        if not allow_missing:
+            raise RuntimeError(f'no libvirt domain "{self._domain}" in "{self._conn.getURI()}"')
+
     @staticmethod
     def _state(domain):
         return domain.info()[0]
@@ -187,7 +190,7 @@ class LibvirtInitVM(_InitVM):
         vcpu_elem.text = str(cpus)
 
     def _build(self):
-        domain = self._get_domain()
+        domain = self._get_domain(allow_missing=True)
         if domain is not None:
             uri = self._conn.getURI()
             raise CliError(142, textwrap.dedent(f"""
@@ -311,7 +314,7 @@ class LibvirtInitVM(_InitVM):
                        check=True)
 
     def destroy(self):
-        domain = self._get_domain()
+        domain = self._get_domain(allow_missing=True)
         if domain is not None:
             with contextlib.suppress(self._libvirt.libvirtError):
                 domain.destroy()
diff --git a/newsfragments/+missing-libvirt-domain.bugfix.rst b/newsfragments/+missing-libvirt-domain.bugfix.rst
new file mode 100644
index 0000000000000000000000000000000000000000..f4e8d90cdbc6bb6f5f5f865c03c6ed5047b85ad9
--- /dev/null
+++ b/newsfragments/+missing-libvirt-domain.bugfix.rst
@@ -0,0 +1 @@
+Print better errors if the initvm libvirt domain is missing.

---
base-commit: de0899c708f2c0b3966daa604f97ceb3c23f4771
change-id: 20250404-libvirt-domain-missing-c01c8ce8b288

Best regards,
-- 
Thomas Weißschuh <thomas.weissschuh at linutronix.de>