key_value: structure for prefs based key value store

envoy_build_config/extensions_build_config.bzl

@@ -15,6 +15,7 @@ EXTENSIONS = {
     "envoy.filters.http.router":                           "//source/extensions/filters/http/router:config",
     "envoy.filters.network.http_connection_manager":       "//source/extensions/filters/network/http_connection_manager:config",
     "envoy.http.original_ip_detection.xff":                "//source/extensions/http/original_ip_detection/xff:config",
+    "envoy.key_value.platform":                            "@envoy_mobile//library/common/extensions/key_value/platform:config",
     "envoy.network.dns_resolver.apple":                    "//source/extensions/network/dns_resolver/apple:config",
     "envoy.retry.options.network_configuration":           "@envoy_mobile//library/common/extensions/retry/options/network_configuration:config",
     "envoy.stat_sinks.metrics_service":                    "//source/extensions/stat_sinks/metrics_service:config",

library/common/extensions/key_value/platform/BUILD

@@ -0,0 +1,31 @@
+load(
+    "@envoy//bazel:envoy_build_system.bzl",
+    "envoy_cc_extension",
+    "envoy_extension_package",
+    "envoy_proto_library",
+)
+
+licenses(["notice"])  # Apache 2
+
+envoy_extension_package()
+
+envoy_proto_library(
+    name = "platform",
+    srcs = ["platform.proto"],
+)
+
+envoy_cc_extension(
+    name = "config",
+    srcs = ["config.cc"],
+    hdrs = ["config.h"],
+    repository = "@envoy",
+    deps = [
+        ":platform_cc_proto",
+        "@envoy//envoy/common:key_value_store_interface",
+        "@envoy//envoy/event:dispatcher_interface",
+        "@envoy//envoy/filesystem:filesystem_interface",
+        "@envoy//envoy/registry",
+        "@envoy//source/common/common:key_value_store_lib",
+        "@envoy_api//envoy/config/common/key_value/v3:pkg_cc_proto",
+    ],
+)

library/common/extensions/key_value/platform/config.cc

@@ -0,0 +1,52 @@
+#include "library/common/extensions/key_value/platform/config.h"
+
+#include "envoy/config/common/key_value/v3/config.pb.h"
+#include "envoy/config/common/key_value/v3/config.pb.validate.h"
+#include "envoy/registry/registry.h"
+
+namespace Envoy {
+namespace Extensions {
+namespace KeyValue {
+
+PlatformKeyValueStore::PlatformKeyValueStore(Event::Dispatcher& dispatcher,
+                                             std::chrono::milliseconds save_interval,
+                                             PlatformInterface& platform_interface,
+                                             const std::string& key)
+    : KeyValueStoreBase(dispatcher, save_interval), platform_interface_(platform_interface),
+      key_(key) {
+  const std::string contents = platform_interface.read(key);
+  if (!parseContents(contents, store_)) {
+    ENVOY_LOG(warn, "Failed to parse key value store contents {}", key);
+  }
+}
+
+void PlatformKeyValueStore::flush() {
+  std::string output;
+  for (const auto& it : store_) {
+    absl::StrAppend(&output, it.first.length(), "\n", it.first, it.second.length(), "\n",
+                    it.second);
+  }
+  platform_interface_.save(key_, output);
+}
+
+KeyValueStorePtr
+PlatformKeyValueStoreFactory::createStore(const Protobuf::Message& config,
+                                          ProtobufMessage::ValidationVisitor& validation_visitor,
+                                          Event::Dispatcher& dispatcher, Filesystem::Instance&) {
+  const auto& typed_config = MessageUtil::downcastAndValidate<
+      const ::envoy::config::common::key_value::v3::KeyValueStoreConfig&>(config,
+                                                                          validation_visitor);
+  const auto file_config = MessageUtil::anyConvertAndValidate<
+      envoymobile::extensions::key_value::platform::PlatformKeyValueStoreConfig>(
+      typed_config.config().typed_config(), validation_visitor);
+  auto milliseconds =
+      std::chrono::milliseconds(DurationUtil::durationToMilliseconds(file_config.save_interval()));
+  return std::make_unique<PlatformKeyValueStore>(
+      dispatcher, milliseconds, platform_interface_.value().get(), file_config.key());
+}
+
+REGISTER_FACTORY(PlatformKeyValueStoreFactory, KeyValueStoreFactory);
+
+} // namespace KeyValue
+} // namespace Extensions
+} // namespace Envoy

library/common/extensions/key_value/platform/config.h

@@ -0,0 +1,64 @@
+#include "envoy/common/key_value_store.h"
+
+#include "source/common/common/key_value_store_base.h"
+
+#include "library/common/extensions/key_value/platform/platform.pb.h"
+#include "library/common/extensions/key_value/platform/platform.pb.validate.h"
+
+namespace Envoy {
+namespace Extensions {
+namespace KeyValue {
+
+class PlatformInterface {
+public:
+  virtual ~PlatformInterface() {}
+  // Save the contents to the key provided. This may be done asynchronously.
+  virtual void save(const std::string& key, const std::string& contents) PURE;
+  // Read the contents of the key provided.
+  virtual std::string read(const std::string& key) const PURE;
+};
+
+// A platform file based key value store, which reads from and saves from based on
+// a key. An example implementation would be flushing to the android prefs file.
+//
+// All keys and values are flushed to a single entry as
+// [length]\n[key][length]\n[value]
+class PlatformKeyValueStore : public KeyValueStoreBase {
+public:
+  PlatformKeyValueStore(Event::Dispatcher& dispatcher, std::chrono::milliseconds save_interval,
+                        PlatformInterface& platform_interface, const std::string& key);
+  // KeyValueStore
+  void flush() override;
+
+private:
+  PlatformInterface& platform_interface_;
+  const std::string key_;
+};
+
+class PlatformKeyValueStoreFactory : public KeyValueStoreFactory {
+public:
+  PlatformKeyValueStoreFactory() {}
+  PlatformKeyValueStoreFactory(PlatformInterface& platform_interface)
+      : platform_interface_(platform_interface) {}
+
+  // KeyValueStoreFactory
+  KeyValueStorePtr createStore(const Protobuf::Message& config,
+                               ProtobufMessage::ValidationVisitor& validation_visitor,
+                               Event::Dispatcher& dispatcher,
+                               Filesystem::Instance& file_system) override;
+
+  // TypedFactory
+  ProtobufTypes::MessagePtr createEmptyConfigProto() override {
+    return ProtobufTypes::MessagePtr{
+        new envoymobile::extensions::key_value::platform::PlatformKeyValueStoreConfig()};
+  }
+
+  std::string name() const override { return "envoy.key_value.platform"; }
+  // TODO(alyssawilk, goaway) the default PlatformInterface should do up calls through Java and this
+  // can be moved to a non-optional reference.
+  OptRef<PlatformInterface> platform_interface_;
+};
+
+} // namespace KeyValue
+} // namespace Extensions
+} // namespace Envoy

library/common/extensions/key_value/platform/platform.proto

@@ -0,0 +1,15 @@
+syntax = "proto3";
+
+package envoymobile.extensions.key_value.platform;
+
+import "google/protobuf/duration.proto";
+
+import "validate/validate.proto";
+
+message PlatformKeyValueStoreConfig {
+  // The key to save the contents to.
+  string key = 1 [(validate.rules).string = {min_len: 1}];
+
+  // The interval at which the key value store should be saved.
+  google.protobuf.Duration save_interval = 2;
+}

test/common/extensions/key_value/platform/BUILD

@@ -0,0 +1,22 @@
+load("@envoy//bazel:envoy_build_system.bzl", "envoy_package")
+load(
+    "@envoy//test/extensions:extensions_build_system.bzl",
+    "envoy_extension_cc_test",
+)
+
+licenses(["notice"])  # Apache 2
+
+envoy_package()
+
+envoy_extension_cc_test(
+    name = "platform_store_test",
+    srcs = ["platform_store_test.cc"],
+    extension_names = ["envoy.key_value.platform"],
+    repository = "@envoy",
+    deps = [
+        "//library/common/extensions/key_value/platform:config",
+        "@envoy//source/common/common:key_value_store_lib",
+        "@envoy//test/mocks/event:event_mocks",
+        "@envoy//test/test_common:file_system_for_test_lib",
+    ],
+)

test/common/extensions/key_value/platform/platform_store_test.cc

@@ -0,0 +1,120 @@
+#include <memory>
+#include <string>
+
+#include "test/mocks/event/mocks.h"
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "library/common/extensions/key_value/platform/config.h"
+#include "library/common/extensions/key_value/platform/platform.pb.h"
+
+using testing::NiceMock;
+
+namespace Envoy {
+namespace Extensions {
+namespace KeyValue {
+namespace {
+
+class TestPlatformInterface : public PlatformInterface {
+  virtual void save(const std::string& key, const std::string& contents) {
+    store_.erase(key);
+    store_.emplace(key, contents);
+  }
+  virtual std::string read(const std::string& key) const {
+    auto it = store_.find(key);
+    if (it == store_.end()) {
+      return "";
+    }
+    return it->second;
+  }
+
+  absl::flat_hash_map<std::string, std::string> store_;
+};
+
+class PlatformStoreTest : public testing::Test {
+protected:
+  PlatformStoreTest() { createStore(); }
+
+  void createStore() {
+    flush_timer_ = new NiceMock<Event::MockTimer>(&dispatcher_);
+    store_ =
+        std::make_unique<PlatformKeyValueStore>(dispatcher_, save_interval_, mock_platform_, key_);
+  }
+  NiceMock<Event::MockDispatcher> dispatcher_;
+  std::string key_{"key"};
+  std::unique_ptr<PlatformKeyValueStore> store_{};
+  std::chrono::seconds save_interval_{5};
+  Event::MockTimer* flush_timer_ = nullptr;
+  TestPlatformInterface mock_platform_;
+};
+
+TEST_F(PlatformStoreTest, Basic) {
+  EXPECT_EQ(absl::nullopt, store_->get("foo"));
+  store_->addOrUpdate("foo", "bar");
+  EXPECT_EQ("bar", store_->get("foo").value());
+  store_->addOrUpdate("foo", "eep");
+  EXPECT_EQ("eep", store_->get("foo").value());
+  store_->remove("foo");
+  EXPECT_EQ(absl::nullopt, store_->get("foo"));
+}
+
+TEST_F(PlatformStoreTest, Persist) {
+  store_->addOrUpdate("foo", "bar");
+  store_->addOrUpdate("by\nz", "ee\np");
+  ASSERT_TRUE(flush_timer_->enabled_);
+  flush_timer_->invokeCallback(); // flush
+  EXPECT_TRUE(flush_timer_->enabled_);
+  // Not flushed as 5ms didn't pass.
+  store_->addOrUpdate("baz", "eep");
+
+  save_interval_ = std::chrono::seconds(0);
+  createStore();
+  KeyValueStore::ConstIterateCb validate = [](const std::string& key, const std::string&) {
+    EXPECT_TRUE(key == "foo" || key == "by\nz");
+    return KeyValueStore::Iterate::Continue;
+  };
+
+  EXPECT_EQ("bar", store_->get("foo").value());
+  EXPECT_EQ("ee\np", store_->get("by\nz").value());
+  EXPECT_FALSE(store_->get("baz").has_value());
+  store_->iterate(validate);
+
+  // This will flush due to 0ms flush interval
+  store_->addOrUpdate("baz", "eep");
+  createStore();
+  EXPECT_TRUE(store_->get("baz").has_value());
+
+  // This will flush due to 0ms flush interval
+  store_->remove("bar");
+  createStore();
+  EXPECT_FALSE(store_->get("bar").has_value());
+}
+
+TEST_F(PlatformStoreTest, Iterate) {
+  store_->addOrUpdate("foo", "bar");
+  store_->addOrUpdate("baz", "eep");
+
+  int full_counter = 0;
+  KeyValueStore::ConstIterateCb validate = [&full_counter](const std::string& key,
+                                                           const std::string&) {
+    ++full_counter;
+    EXPECT_TRUE(key == "foo" || key == "baz");
+    return KeyValueStore::Iterate::Continue;
+  };
+  store_->iterate(validate);
+  EXPECT_EQ(2, full_counter);
+
+  int stop_early_counter = 0;
+  KeyValueStore::ConstIterateCb stop_early = [&stop_early_counter](const std::string&,
+                                                                   const std::string&) {
+    ++stop_early_counter;
+    return KeyValueStore::Iterate::Break;
+  };
+  store_->iterate(stop_early);
+  EXPECT_EQ(1, stop_early_counter);
+}
+
+} // namespace
+} // namespace KeyValue
+} // namespace Extensions
+} // namespace Envoy