openstack provider: ignore ec2 metadata if not present

Signed-off-by: Riccardo Piccoli <rpiccoli@redhat.com>

Author: rccrdpccl

docs/release-notes.md

@@ -11,6 +11,7 @@ Major changes:
 Minor changes:
 
 - ProxmoxVE: Fixed instance boot without config drive
+- OpenStack: do not fail if ec2 metadata is not found
 
 Packaging changes:
 

src/providers/openstack/configdrive.rs

@@ -101,13 +101,19 @@ impl OpenstackConfigDrive {
     }
 
     /// The metadata is stored as key:value pair in ec2/latest/meta-data.json file
-    fn read_metadata_ec2(&self) -> Result<MetadataEc2JSON> {
+    fn read_metadata_ec2(&self) -> Result<Option<MetadataEc2JSON>> {
+        use std::io::ErrorKind::NotFound;
+
         let filename = self.metadata_dir("ec2").join("meta-data.json");
-        let file =
-            File::open(&filename).with_context(|| format!("failed to open file '{filename:?}'"))?;
+        let file = match File::open(&filename) {
+            Ok(file) => file,
+            Err(e) if e.kind() == NotFound => return Ok(None),
+            Err(e) => return Err(e).with_context(|| format!("failed to open file '{filename:?}'")),
+        };
         let bufrd = BufReader::new(file);
         Self::parse_metadata_ec2(bufrd)
             .with_context(|| format!("failed to parse file '{filename:?}'"))
+            .map(Some)
     }
 
     /// The metadata is stored as key:value pair in openstack/latest/meta_data.json file
@@ -144,17 +150,20 @@ impl OpenstackConfigDrive {
 impl MetadataProvider for OpenstackConfigDrive {
     fn attributes(&self) -> Result<HashMap<String, String>> {
         let mut out = HashMap::with_capacity(6);
-        let metadata_ec2: MetadataEc2JSON = self.read_metadata_ec2()?;
         let metadata_openstack: MetadataOpenstackJSON = self.read_metadata_openstack()?;
         if let Some(hostname) = metadata_openstack.hostname {
             out.insert("OPENSTACK_HOSTNAME".to_string(), hostname);
         }
-        if let Some(instance_id) = metadata_ec2.instance_id {
-            out.insert("OPENSTACK_INSTANCE_ID".to_string(), instance_id);
-        }
         if let Some(uuid) = metadata_openstack.uuid {
             out.insert("OPENSTACK_INSTANCE_UUID".to_string(), uuid);
         }
+
+        let Some(metadata_ec2) = self.read_metadata_ec2()? else {
+            return Ok(out);
+        };
+        if let Some(instance_id) = metadata_ec2.instance_id {
+            out.insert("OPENSTACK_INSTANCE_ID".to_string(), instance_id);
+        }
         if let Some(instance_type) = metadata_ec2.instance_type {
             out.insert("OPENSTACK_INSTANCE_TYPE".to_string(), instance_type);
         }