Expose combination of provider + core stats (#5696)

* Expose combination of provider + core stats

* Non-existing core stats

packages/rpc-core/src/bundle.ts

@@ -7,7 +7,7 @@ import type { StorageKey, Vec } from '@polkadot/types';
 import type { Hash } from '@polkadot/types/interfaces';
 import type { AnyJson, AnyNumber, Codec, DefinitionRpc, DefinitionRpcExt, DefinitionRpcSub, Registry } from '@polkadot/types/types';
 import type { Memoized } from '@polkadot/util/types';
-import type { RpcInterfaceMethod } from './types/index.js';
+import type { RpcCoreStats, RpcInterfaceMethod } from './types/index.js';
 
 import { Observable, publishReplay, refCount } from 'rxjs';
 
@@ -94,6 +94,8 @@ export class RpcCore {
   readonly #isPedantic: boolean;
   readonly #registryDefault: Registry;
   readonly #storageCache = new Map<string, Codec>();
+  #storageCacheHits = 0;
+  #storageCacheSize = 0;
 
   #getBlockRegistry?: (blockHash: Uint8Array) => Promise<{ registry: Registry }>;
   #getBlockHash?: (blockNumber: AnyNumber) => Promise<Uint8Array>;
@@ -147,6 +149,23 @@ export class RpcCore {
     return this.provider.disconnect();
   }
 
+  /**
+   * @description Returns the underlying core stats, including those from teh provider
+   */
+  public get stats (): RpcCoreStats | undefined {
+    const stats = this.provider.stats;
+
+    return stats
+      ? {
+        ...stats,
+        core: {
+          cacheHits: this.#storageCacheHits,
+          cacheSize: this.#storageCacheSize
+        }
+      }
+      : undefined;
+  }
+
   /**
    * @description Sets a registry swap (typically from Api)
    */
@@ -453,6 +472,8 @@ export class RpcCore {
       const cached = this.#storageCache.get(hexKey);
 
       if (cached) {
+        this.#storageCacheHits++;
+
         return cached;
       }
     }
@@ -470,6 +491,7 @@ export class RpcCore {
     // clearing of it, so very long running processes (not just a couple of hours, longer)
     // will increase memory beyond what is allowed.
     this.#storageCache.set(hexKey, codec);
+    this.#storageCacheSize++;
 
     return codec;
   }

packages/rpc-core/src/types/base.ts

@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import type { Observable } from 'rxjs';
+import type { ProviderInterface } from '@polkadot/rpc-provider/types';
 import type { AnyFunction, Codec, DefinitionRpc } from '@polkadot/types/types';
 
 export interface RpcInterfaceMethod {
@@ -14,3 +15,14 @@ export type AugmentedRpc<F extends AnyFunction> = F & {
   raw: <T> (...params: Parameters<F>) => Observable<T>;
   meta: DefinitionRpc;
 };
+
+/** Stats from the rpc-core layer, including the provider stats */
+export interface RpcCoreStats extends NonNullable<ProviderInterface['stats']> {
+  /** Internal stats for the rpc-core layer */
+  core: {
+    /** The number of values retrieved from the core cache */
+    cacheHits: number;
+    /** The number of entries in the core cache */
+    cacheSize: number;
+  }
+}