Create ETCD get / set functions (#4)

* Doc: Added a proposal for swift-etcd-client API

* Update 0001-swift-etcd-api.md: made the doc for get function

* updated key-val operation

* feat: added docke-compose and dockerfile

* feat: added docke-compose and dockerfile

* fix: update dockerfile

* feat: add proto and create etcd client

* fix: Create correct proto files and add http and annotations

* fix: fixed package.swift and created main entrypoint

* fix: create get / set and executable target in package.swift

* fix: Update ETCD client with PR comments

* fix: PR comment fixes

* fix: make ETCDValue conform to generic types

* fix: Update ETCDClient and Example to use Sequence<UInt8>

* Added tests to ETCD get / set methods

* Add documentation for get / set

* Cleaned up ETCDClient files and updated with copyright information. Deleted ETCDValue as it was no longer being used.

* Rename ETCDGetSetTests

* Update eventLoopGroup to singleton in test

* Remove forced unwrap of Etcdserverpb_KVNIOClient

---------

Co-authored-by: “Ayushi <“[email protected]”>

Author: ayushi2103

Package.swift

@@ -33,6 +33,8 @@ let package = Package(
         .package(url: "https://github.com/apple/swift-nio.git", from: "2.56.0"),
         .package(url: "https://github.com/apple/swift-log.git", from: "1.0.0"),
         .package(url: "https://github.com/swift-server/swift-service-lifecycle.git", from: "2.0.0"),
+        .package(url: "https://github.com/grpc/grpc-swift.git", from: "1.21.0"),
+        .package(url: "https://github.com/apple/swift-protobuf.git", from: "1.14.0"),
     ],
     targets: [
         .target(
@@ -43,6 +45,8 @@ let package = Package(
                 .product(name: "NIOEmbedded", package: "swift-nio"),
                 .product(name: "Logging", package: "swift-log"),
                 .product(name: "ServiceLifecycle", package: "swift-service-lifecycle"),
+                .product(name: "GRPC", package: "grpc-swift"),
+                .product(name: "SwiftProtobuf", package: "swift-protobuf"),
             ]
         ),
         .testTarget(
@@ -51,9 +55,7 @@ let package = Package(
         ),
         .executableTarget(
             name: "ETCDExample",
-            dependencies: [
-                .target(name: "ETCD"),
-            ]
+            dependencies: ["ETCD"]
         ),
     ]
 )

Sources/ETCD/ETCDClient.swift

@@ -0,0 +1,88 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the swift-etcd-client-gsoc open source project
+//
+// Copyright (c) 2024 Apple Inc. and the swift-etcd-client-gsoc project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of swift-etcd-client-gsoc project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import Foundation
+import GRPC
+import NIO
+import SwiftProtobuf
+
+public final class EtcdClient: @unchecked Sendable {
+    private let host: String
+    private let port: Int
+    private var group: EventLoopGroup
+    private var connection: ClientConnection
+    private var client: Etcdserverpb_KVNIOClient
+
+    /// Initialize a new ETCD Connection.
+    ///
+    /// - Parameters:
+    ///   - host: The host address of the ETCD server.
+    ///   - port: The port number of the ETCD server.
+    ///   - eventLoopGroup: The event loop group to use for this connection.
+    public init(host: String, port: Int, eventLoopGroup: EventLoopGroup) {
+        self.host = host
+        self.port = port
+        self.group = eventLoopGroup
+        self.connection = ClientConnection.insecure(group: self.group)
+            .connect(host: host, port: port)
+        self.client = Etcdserverpb_KVNIOClient(channel: self.connection)
+    }
+
+    /// Sets a value for a specified key in the ETCD server.
+    ///
+    /// - Parameters:
+    ///   - key: The key for which the value is to be set. Parameter is of type Sequence<UInt8>.
+    ///   - value: The ETCD value to set for the key. Parameter is of type Sequence<UInt8>.
+    public func set(_ key: some Sequence<UInt8>, value: some Sequence<UInt8>) async throws {
+        var putRequest = Etcdserverpb_PutRequest()
+        putRequest.key = Data(key)
+        putRequest.value = Data(value)
+        let call = client.put(putRequest)
+        _ = try await call.response.get()
+    }
+    
+    /// Sets a value for a specified key in the ETCD server.
+    ///
+    /// - Parameters:
+    ///   - key: The key for which the value is to be set. Parameter is of type String,
+    ///   - value: The ETCD value to set for the key. Parameter is of type String.
+    public func set(_ key: String, value: String) async throws {
+        try await set(key.utf8, value: value.utf8)
+    }
+
+    /// Fetch the value for a key from the ETCD server.
+    ///
+    /// - Parameter key: The key to fetch the value for. Parameter is of type Sequence<UInt8>.
+    /// - Returns: A `Value` containing the fetched value, or `nil` if no value was found.
+    public func get(_ key: some Sequence<UInt8>) async throws -> Data? {
+        var rangeRequest = Etcdserverpb_RangeRequest()
+        rangeRequest.key = Data(key)
+
+        let call = client.range(rangeRequest)
+        let response = try await call.response.get()
+        
+        guard let kv = response.kvs.first else {
+            return nil
+        }
+        return kv.value
+    }
+    
+    /// Fetch the value for a key from the ETCD server.
+    ///
+    /// - Parameter key: The key to fetch the value for. Parameter is of type Sequence<UInt8>.
+    /// - Returns: A `Value` containing the fetched value, or `nil` if no value was found.
+    public func get(_ key: String) async throws -> Data? {
+        return try await get(key.utf8)
+    }
+}

Sources/ETCD/empty.swift

@@ -0,0 +1,31 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+syntax = "proto3";
+
+package google.api;
+
+import "http.proto";
+import "google/protobuf/descriptor.proto";
+
+option go_package = "google.golang.org/genproto/googleapis/api/annotations;annotations";
+option java_multiple_files = true;
+option java_outer_classname = "AnnotationsProto";
+option java_package = "com.google.api";
+option objc_class_prefix = "GAPI";
+
+extend google.protobuf.MethodOptions {
+  // See `HttpRule`.
+  HttpRule http = 72295728;
+}