[pve-devel] [PATCH] pve-rs: fabrics: handle missing running-config and no fabrics config

[Gabriel Goller]

Correctly handle if there is a missing `/etc/pve/sdn/.running-config`
file. This happens, e.g. on a clean installation without any sdn "apply"
activation. Also handle a config where there is no fabric configured.
The `status()` functions gets called every few seconds to populate the
network resources in pve, so don't return an error if there is no
running-config or no fabric config. The other functions (neighbors,
interfaces, routes) only get called by the api, so we can return an
error on those.

Reported-by: Thomas Lamprecht <t.lamprecht at proxmox.com>
Reported-by: Stoiko Ivanov <s.ivanov at proxmox.com>
Signed-off-by: Gabriel Goller <g.goller at proxmox.com>
---
 pve-rs/src/bindings/sdn/fabrics.rs | 36 ++++++++++++++++++++++++------
 pve-rs/src/sdn/status.rs           | 10 ++++++---
 2 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/pve-rs/src/bindings/sdn/fabrics.rs b/pve-rs/src/bindings/sdn/fabrics.rs
index c9e5cf526c77..54606e7b6bb9 100644
--- a/pve-rs/src/bindings/sdn/fabrics.rs
+++ b/pve-rs/src/bindings/sdn/fabrics.rs
@@ -595,14 +595,21 @@ pub mod pve_rs_sdn_fabrics {
     /// Read and parse the running-config and get the fabrics section
     ///
     /// This will return a valid FabricConfig. Note that we read the file manually and not through
-    /// the cluster filesystem as with perl, so this will be slower.
-    fn get_fabrics_config() -> Result<Valid<FabricConfig>, anyhow::Error> {
+    /// the cluster filesystem as with perl, so this will be slower. If the running config exists,
+    /// but no fabric is configured, `Ok(None)` is returned.
+    fn get_fabrics_config() -> Result<Option<Valid<FabricConfig>>, anyhow::Error> {
         let raw_config = std::fs::read_to_string("/etc/pve/sdn/.running-config")?;
         let running_config: RunningConfig =
             serde_json::from_str(&raw_config).with_context(|| "error parsing running-config")?;
-        let section_config = SectionConfigData::from_iter(running_config.fabrics.ids);
-        FabricConfig::from_section_config(section_config)
-            .with_context(|| "error converting section config to fabricconfig")
+        let Some(fabrics) = running_config.fabrics else {
+            return Ok(None);
+        };
+        let section_config = SectionConfigData::from_iter(fabrics.ids);
+        Some(
+            FabricConfig::from_section_config(section_config)
+                .with_context(|| "error converting section config to fabricconfig"),
+        )
+        .transpose()
     }
 
     /// Get the routes that have been learned and distributed by this specific fabric on this node.
@@ -614,6 +621,9 @@ pub mod pve_rs_sdn_fabrics {
     fn routes(fabric_id: FabricId) -> Result<Vec<status::RouteStatus>, Error> {
         // Read fabric config to get protocol of fabric
         let config = get_fabrics_config()?;
+        let Some(config) = config else {
+            anyhow::bail!("no fabrics configured");
+        };
 
         let fabric = config.get_fabric(&fabric_id)?;
         match fabric {
@@ -679,6 +689,9 @@ pub mod pve_rs_sdn_fabrics {
     fn neighbors(fabric_id: FabricId) -> Result<status::NeighborStatus, Error> {
         // Read fabric config to get protocol of fabric
         let config = get_fabrics_config()?;
+        let Some(config) = config else {
+            anyhow::bail!("no fabrics configured");
+        };
 
         let fabric = config.get_fabric(&fabric_id)?;
 
@@ -734,6 +747,9 @@ pub mod pve_rs_sdn_fabrics {
     fn interfaces(fabric_id: FabricId) -> Result<status::InterfaceStatus, Error> {
         // Read fabric config to get protocol of fabric
         let config = get_fabrics_config()?;
+        let Some(config) = config else {
+            anyhow::bail!("no fabrics configured");
+        };
 
         let fabric = config.get_fabric(&fabric_id)?;
 
@@ -789,6 +805,14 @@ pub mod pve_rs_sdn_fabrics {
     /// config. If there are, show "ok" as status, otherwise "not ok".
     #[export]
     fn status() -> Result<HashMap<FabricId, status::Status>, Error> {
+        // This gets called every few seconds from pve to get the status of the fabrics into the
+        // network resources. It is possible that the .running-config doesn't exist or no fabric is
+        // configured -- in that case just return nothing.
+        let config = get_fabrics_config();
+        let Ok(Some(config)) = config else {
+            return Ok(HashMap::new());
+        };
+
         let openfabric_ipv4_routes_string = String::from_utf8(
             Command::new("sh")
                 .args(["-c", "vtysh -c 'show ip route openfabric json'"])
@@ -831,8 +855,6 @@ pub mod pve_rs_sdn_fabrics {
                 .with_context(|| "error parsing ospf routes")?
         };
 
-        let config = get_fabrics_config()?;
-
         let route_status = status::RoutesParsed {
             openfabric: openfabric_routes,
             ospf: ospf_routes,
diff --git a/pve-rs/src/sdn/status.rs b/pve-rs/src/sdn/status.rs
index 78b55502b837..e1e336297ac9 100644
--- a/pve-rs/src/sdn/status.rs
+++ b/pve-rs/src/sdn/status.rs
@@ -178,7 +178,7 @@ pub struct RoutesParsed {
 /// Config used to parse the fabric part of the running-config
 #[derive(Deserialize)]
 pub struct RunningConfig {
-    pub fabrics: FabricsRunningConfig,
+    pub fabrics: Option<FabricsRunningConfig>,
 }
 
 /// Map of ids for all the fabrics in the running-config
@@ -647,7 +647,9 @@ mod tests {
 
         let running_config: RunningConfig =
             serde_json::from_str(raw_config).expect("error parsing running-config");
-        let section_config = SectionConfigData::from_iter(running_config.fabrics.ids);
+        let section_config = SectionConfigData::from_iter(
+            running_config.fabrics.expect("no fabrics configured").ids,
+        );
         FabricConfig::from_section_config(section_config)
             .expect("error converting section config to fabricconfig")
     }
@@ -695,7 +697,9 @@ mod tests {
             "#;
         let running_config: RunningConfig =
             serde_json::from_str(raw_config).expect("error parsing running-config");
-        let section_config = SectionConfigData::from_iter(running_config.fabrics.ids);
+        let section_config = SectionConfigData::from_iter(
+            running_config.fabrics.expect("no fabrics configured").ids,
+        );
         FabricConfig::from_section_config(section_config)
             .expect("error converting section config to fabricconfig")
     }
-- 
2.47.3