From 0c298ce189143b671cda50447db4dca05afc09e8 Mon Sep 17 00:00:00 2001
From: Arne Luenser <arne.luenser@ory.sh>
Date: Fri, 15 Sep 2023 12:16:43 +0200
Subject: [PATCH] feat: cache OPL when loading from HTTP(S)

---
 internal/driver/config/opl_cache_test.go      | 52 +++++++++++++++++++
 .../config/opl_config_namespace_watcher.go    | 30 ++++++++++-
 2 files changed, 80 insertions(+), 2 deletions(-)
 create mode 100644 internal/driver/config/opl_cache_test.go

diff --git a/internal/driver/config/opl_cache_test.go b/internal/driver/config/opl_cache_test.go
new file mode 100644
index 000000000..61dd4d8ac
--- /dev/null
+++ b/internal/driver/config/opl_cache_test.go
@@ -0,0 +1,52 @@
+// Copyright © 2023 Ory Corp
+// SPDX-License-Identifier: Apache-2.0
+
+package config
+
+import (
+	"context"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/ory/x/configx"
+	"github.com/ory/x/logrusx"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNewOPLConfigWatcher(t *testing.T) {
+	hits := 0
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		hits++
+		io.WriteString(w, testOPL)
+	}))
+	t.Cleanup(ts.Close)
+	ctx := context.Background()
+	cfg, err := NewDefault(ctx, nil, logrusx.New("", ""), configx.SkipValidation())
+	require.NoError(t, err)
+	cw, err := newOPLConfigWatcher(ctx, cfg, ts.URL)
+	require.NoError(t, err)
+	require.Equal(t, 1, hits, "HTTP request made")
+	_, err = cw.GetNamespaceByName(ctx, "User")
+	require.NoError(t, err)
+	_, err = cw.GetNamespaceByName(ctx, "Document")
+	require.NoError(t, err)
+
+	cache.Wait()
+
+	cw, err = newOPLConfigWatcher(ctx, cfg, ts.URL)
+	require.NoError(t, err)
+	require.Equal(t, 1, hits, "content was cached")
+	_, err = cw.GetNamespaceByName(ctx, "User")
+	require.NoError(t, err)
+	_, err = cw.GetNamespaceByName(ctx, "Document")
+	require.NoError(t, err)
+}
+
+var testOPL = `
+import { Namespace } from "@ory/keto-namespace-types"
+
+class User implements Namespace {}
+class Document implements Namespace {}
+`
diff --git a/internal/driver/config/opl_config_namespace_watcher.go b/internal/driver/config/opl_config_namespace_watcher.go
index f07e21344..bca9086a7 100644
--- a/internal/driver/config/opl_config_namespace_watcher.go
+++ b/internal/driver/config/opl_config_namespace_watcher.go
@@ -4,11 +4,14 @@
 package config
 
 import (
+	"bytes"
 	"context"
 	"fmt"
 	"io"
 	"sync"
+	"time"
 
+	"github.com/dgraph-io/ristretto"
 	"github.com/ory/x/logrusx"
 	"github.com/ory/x/urlx"
 	"github.com/ory/x/watcherx"
@@ -33,7 +36,14 @@ type (
 	}
 )
 
-var _ namespace.Manager = (*oplConfigWatcher)(nil)
+var (
+	_        namespace.Manager = (*oplConfigWatcher)(nil)
+	cache, _                   = ristretto.NewCache(&ristretto.Config{
+		MaxCost:     20_000_000, // 20 MB max size, each item ca. 10 KB => max 2000 items
+		NumCounters: 20_000,     // max 2000 items => 20000 counters
+		BufferItems: 64,
+	})
+)
 
 func newOPLConfigWatcher(ctx context.Context, c *Config, target string) (*oplConfigWatcher, error) {
 	nw := &oplConfigWatcher{
@@ -51,7 +61,7 @@ func newOPLConfigWatcher(ctx context.Context, c *Config, target string) (*oplCon
 	switch targetUrl.Scheme {
 	case "file", "":
 		return nw, watchTarget(ctx, target, nw, c.l)
-	case "http", "https", "base64":
+	case "base64":
 		file, err := c.Fetcher().FetchContext(ctx, target)
 		if err != nil {
 			return nil, err
@@ -59,6 +69,22 @@ func newOPLConfigWatcher(ctx context.Context, c *Config, target string) (*oplCon
 		nw.files.byPath[targetUrl.String()] = file
 		nw.parseFiles()
 		return nw, err
+	case "http", "https":
+		var file io.Reader
+		if item, ok := cache.Get(target); ok {
+			file = bytes.NewReader(item.([]byte))
+		} else {
+			buf, err := c.Fetcher().FetchContext(ctx, target)
+			if err != nil {
+				return nil, err
+			}
+			b := buf.Bytes()
+			cache.SetWithTTL(target, b, int64(cap(b)), 30*time.Minute)
+			file = bytes.NewReader(b)
+		}
+		nw.files.byPath[targetUrl.String()] = file
+		nw.parseFiles()
+		return nw, err
 	default:
 		return nil, fmt.Errorf("unexpected url scheme: %q", targetUrl.Scheme)
 	}