pool: add GetInstances method, that returns current instances connections state

CHANGELOG.md

@@ -11,6 +11,8 @@ Versioning](http://semver.org/spec/v2.0.0.html) except to the first release.
 ### Added
 
 - Extend box with replication information (#427).
+- The GetConnections method has been added,
+which is necessary to monitor the current state of the pool (#428).
 
 ### Changed
 

pool/connection_pool.go

@@ -1506,3 +1506,21 @@ func isFeatureInSlice(expected iproto.Feature, actualSlice []iproto.Feature) boo
 	}
 	return false
 }
+
+// GetInstances retrieves a slice of Instance objects representing the connections in the pool.
+func (p *ConnectionPool) GetInstances() []Instance {
+	p.endsMutex.Lock()
+	defer p.endsMutex.Unlock()
+
+	res := make([]Instance, 0, len(p.ends))
+
+	for _, end := range p.ends {
+		res = append(res, Instance{
+			Name:   end.name,
+			Dialer: end.dialer,
+			Opts:   end.opts,
+		})
+	}
+
+	return res
+}

pool/connection_pool_test.go

@@ -3449,6 +3449,27 @@ func TestWatcher_Unregister_concurrent(t *testing.T) {
 	wg.Wait()
 }
 
+func TestConnectionPool_GetInstances(t *testing.T) {
+	var tCases [][]pool.Instance
+
+	tCases = append(tCases, makeInstances([]string{servers[0], servers[1]}, connOpts))
+	tCases = append(tCases, makeInstances([]string{servers[0], servers[1], servers[3]}, connOpts))
+	tCases = append(tCases, makeInstances([]string{servers[0]}, connOpts))
+
+	for _, tc := range tCases {
+		ctx, cancel := test_helpers.GetPoolConnectContext()
+		connPool, err := pool.Connect(ctx, tc)
+		cancel()
+		require.Nilf(t, err, "failed to connect")
+		require.NotNilf(t, connPool, "conn is nil after Connect")
+
+		poolInstns := connPool.GetInstances()
+		require.ElementsMatch(t, tc, poolInstns)
+		connPool.Close()
+	}
+
+}
+
 // runTestMain is a body of TestMain function
 // (see https://pkg.go.dev/testing#hdr-Main).
 // Using defer + os.Exit is not works so TestMain body