Add CLI arg to skip the update of the local registry

.github/workflows/msd-diff.yaml

@@ -34,11 +34,9 @@ jobs:
         run: |
           set -exuo pipefail
           REGISTRY_DIR_MAIN="$HOME/tmp/main-registry"
-          REGISTRY_DIR_BRANCH="$HOME/tmp/branch-registry"
           TARGETS_DIR_MAIN="$HOME/main-targets"
           TARGETS_DIR_BRANCH="$HOME/branch-targets"
           mkdir -p "$REGISTRY_DIR_MAIN" \
-                  "$REGISTRY_DIR_BRANCH" \
                   "$TARGETS_DIR_MAIN" \
                   "$TARGETS_DIR_BRANCH"
           chmod +x multiservice-discovery
@@ -48,7 +46,8 @@ jobs:
               --render-prom-targets-to-stdout > "$TARGETS_DIR_MAIN/targets.json"
           # Run multiservice-discovery for branch targets with bazel
           bazel run //rs/ic-observability/multiservice-discovery -- \
-              --targets-dir "$REGISTRY_DIR_BRANCH" \
+              --targets-dir "$REGISTRY_DIR_MAIN" \
+              --skip-update-local-registry \
               --render-prom-targets-to-stdout > "$TARGETS_DIR_BRANCH/targets.json"
           echo "targets_main=$TARGETS_DIR_MAIN" >> $GITHUB_OUTPUT
           echo "targets_branch=$TARGETS_DIR_BRANCH" >> $GITHUB_OUTPUT

rs/ic-observability/multiservice-discovery/src/definition.rs

@@ -11,6 +11,7 @@ use service_discovery::IcServiceDiscovery;
 use service_discovery::IcServiceDiscoveryError;
 use service_discovery::TargetGroup;
 use service_discovery::{registry_sync::sync_local_registry, IcServiceDiscoveryImpl};
+use slog::error;
 use slog::{debug, info, warn, Logger};
 use std::collections::BTreeMap;
 use std::collections::BTreeSet;
@@ -143,13 +144,27 @@ impl TestDefinition {
     }
 
     /// Syncs the registry update the in-memory cache then stops.
-    pub async fn sync_and_stop(&self) {
-        let _ = self.running_def.initial_registry_sync().await;
-        // if self.initial_registry_sync().await.is_err() {
-        // FIXME: Error has been logged, but ideally, it should be handled.
-        // E.g. telemetry should collect this.
-        // return;
-        // }
+    pub async fn sync_and_stop(&self, skip_update_local_registry: bool) {
+        if let Err(e) = if skip_update_local_registry {
+            sync_local_registry(
+                self.running_def.definition.log.clone(),
+                self.running_def.definition.registry_path.join("targets"),
+                self.running_def.definition.nns_urls.clone(),
+                true,
+                self.running_def.definition.public_key,
+                &self.running_def.stop_signal,
+            )
+            .await
+        } else {
+            self.running_def.initial_registry_sync().await
+        } {
+            error!(
+                self.running_def.definition.log,
+                "Error while running initial sync for definition named '{}': {:?}", self.running_def.definition.name, e
+            );
+            return; 
+        };
+
         let _ = self
             .running_def
             .definition

rs/ic-observability/multiservice-discovery/src/main.rs

@@ -50,7 +50,7 @@ fn main() {
         ) -> Option<RunningDefinition> {
             let def = get_mainnet_definition(cli_args, log.clone());
             let mut test_def = TestDefinition::new(def, RunningDefinitionsMetrics::new());
-            let sync_fut = test_def.sync_and_stop();
+            let sync_fut = test_def.sync_and_stop(cli_args.skip_update_local_registry);
             tokio::select! {
                 _ = sync_fut => {
                     info!(log, "Synchronization done");
@@ -207,6 +207,16 @@ the Prometheus targets of mainnet as a JSON structure on stdout.
     )]
     render_prom_targets_to_stdout: bool,
 
+    #[clap(
+        long = "skip-update-local-registry",
+        default_value = "false",
+        action,
+        help = r#"
+Used for testing: Whether to skip the update of the local mainnet registry.
+"#
+    )]
+    skip_update_local_registry: bool,
+
     #[clap(
         long = "networks-state-file",
         default_value = None,