[ISSUE-35] Be more resilient against unexpected cluster specs

Fixes #35

When deserializing clusters discovered in the MCC instance, try
each one independently rather than in bulk, and keep the ones
that succeed instead of throwing them all out if just one fails.

Also, this implicitly ignores clusters that do not yet have any
nodes, presumably because they have just been provisioned and
nodes haven't been created yet. This is because those clusters
will not have a `providerStatus` object which contains information
required to generate kubeconfig files, such as the
`apiServerCertificate`.

src/cc/store/ClustersProvider.js

@@ -120,16 +120,22 @@ const _deserializeClustersList = function (body) {
     return { error: strings.clusterProvider.error.invalidClusterPayload() };
   }
 
-  try {
-    return { data: body.items.map((item) => new Cluster(item)) };
-  } catch (err) {
-    // eslint-disable-next-line no-console -- OK to show errors
-    console.error(
-      `[${pkg.name}/ClustersProvider._deserializeClustersList()] ERROR: ${err.message}`,
-      err
-    );
-    return { error: strings.clustersProvider.errors.invalidCluster() };
-  }
+  return {
+    data: body.items
+      .map((item, idx) => {
+        try {
+          return new Cluster(item);
+        } catch (err) {
+          // eslint-disable-next-line no-console -- OK to show errors
+          console.error(
+            `[${pkg.name}/ClustersProvider._deserializeClustersList()] ERROR with cluster ${idx}: ${err.message}`,
+            err
+          );
+          return undefined;
+        }
+      })
+      .filter((cl) => !!cl), // eliminate failed clusters (`undefined` items)
+  };
 };
 
 /**

src/strings.ts

@@ -160,8 +160,6 @@ export const clustersProvider: Dict = {
       'Encountered at least one namespace with unexpected or missing metadata.',
     invalidClusterPayload: () =>
       'Failed to parse cluster payload: Unexpected data format.',
-    invalidCluster: () =>
-      'Encountered at least one cluster with unexpected or missing metadata.',
   },
 };