Merge pull request #31 from Clearcals/susheel/master/pubsub_setup

Added support for Google PubSub

Package.swift

@@ -23,10 +23,13 @@ let package = Package(
         .library(
             name: "CloudTranslation",
             targets: ["CloudTranslation"]),
+        .library(
+            name: "CloudPubSub",
+            targets: ["CloudPubSub"]),
     ],
     dependencies: [
         .package(url: "https://github.com/vapor/vapor.git", from: "4.0.0"),
-        .package(url: "https://github.com/vapor-community/google-cloud-kit.git", from: "1.0.0-rc")
+        .package(url: "https://github.com/vapor-community/google-cloud-kit.git", from: "1.0.0-rc.7")
     ],
     targets: [
         .target(
@@ -64,5 +67,12 @@ let package = Package(
                 .product(name: "GoogleCloudTranslation", package: "google-cloud-kit"),
                 .target(name: "GoogleCloud")
         ]),
+        .target(
+            name: "CloudPubSub",
+            dependencies: [
+                .product(name: "Vapor", package: "vapor"),
+                .product(name: "GoogleCloudPubSub", package: "google-cloud-kit"),
+                .target(name: "GoogleCloud")
+        ]),
     ]
 )

README.md

@@ -26,5 +26,7 @@ You can check each supported API's README for a getting started guide.
 
 [x] [CloudTranslation](/Sources/CloudTranslation/README.md)
 
+[x] [CloudPubSub](/Sources/CloudPubSub/README.md)
+
 ### A More detailed guide can be found [here](https://github.com/vapor-community/google-cloud-kit).
 

Sources/CloudPubSub/GoogleCloudPubSubAPI.swift

@@ -0,0 +1,111 @@
+//
+//  GoogleCloudPubSubAPI.swift
+//  
+//
+//  Created by Susheel Athmakuri on 6/20/21.
+//
+
+import Vapor
+@_exported import PubSub
+@_exported import GoogleCloud
+
+extension Application.GoogleCloudPlatform {
+    private struct CloudPubSubAPIKey: StorageKey {
+        typealias Value = GoogleCloudPubSubAPI
+    }
+
+    private struct CloudPubSubConfigurationKey: StorageKey {
+        typealias Value = GoogleCloudPubSubConfiguration
+    }
+
+    private struct CloudSPubSubHTTPClientKey: StorageKey, LockKey {
+        typealias Value = HTTPClient
+    }
+
+    public var pubsub: GoogleCloudPubSubAPI {
+        get {
+            if let existing = self.application.storage[CloudPubSubAPIKey.self] {
+                return existing
+            } else {
+                return .init(application: self.application,
+                             eventLoop: self.application.eventLoopGroup.next())
+            }
+        }
+
+        nonmutating set {
+            self.application.storage[CloudPubSubAPIKey.self] = newValue
+        }
+    }
+
+    public struct GoogleCloudPubSubAPI {
+        public let application: Application
+        public let eventLoop: EventLoop
+
+        /// A client used to interact with the `GoogleCloudPubSub` API.
+        public var client: GoogleCloudPubSubClient {
+            do {
+                let new = try GoogleCloudPubSubClient(credentials: self.application.googleCloud.credentials, config: self.configuration, httpClient: self.http, eventLoop: self.eventLoop)
+                return new
+            } catch {
+                fatalError("\(error.localizedDescription)")
+            }
+        }
+
+        /// The configuration for using `GoogleCloudPubSub` APIs.
+        public var configuration: GoogleCloudPubSubConfiguration {
+            get {
+                if let configuration = application.storage[CloudPubSubConfigurationKey.self] {
+                   return configuration
+                } else {
+                    fatalError("Cloud PubSub configuration has not been set. Use app.googleCloud.pubsub.configuration = ...")
+                }
+            }
+            set {
+                if application.storage[CloudPubSubConfigurationKey.self] == nil {
+                    application.storage[CloudPubSubConfigurationKey.self] = newValue
+                } else {
+                    fatalError("Attempting to override credentials configuration after being set is not allowed.")
+                }
+            }
+        }
+
+        /// Custom `HTTPClient` that ignores unclean SSL shutdown.
+        public var http: HTTPClient {
+            if let existing = application.storage[CloudSPubSubHTTPClientKey.self] {
+                return existing
+            } else {
+                let lock = application.locks.lock(for: CloudSPubSubHTTPClientKey.self)
+                lock.lock()
+                defer { lock.unlock() }
+                if let existing = application.storage[CloudSPubSubHTTPClientKey.self] {
+                    return existing
+                }
+                let new = HTTPClient(
+                    eventLoopGroupProvider: .shared(application.eventLoopGroup),
+                    configuration: HTTPClient.Configuration(ignoreUncleanSSLShutdown: true)
+                )
+                application.storage.set(CloudSPubSubHTTPClientKey.self, to: new) {
+                    try $0.syncShutdown()
+                }
+                return new
+            }
+        }
+    }
+}
+
+extension Request {
+    private struct GoogleCloudPubSubKey: StorageKey {
+        typealias Value = GoogleCloudPubSubClient
+    }
+
+    /// A client used to interact with the `GoogleCloudPubSub` API
+    public var gcPubSub: GoogleCloudPubSubClient {
+        if let existing = application.storage[GoogleCloudPubSubKey.self] {
+            return existing.hopped(to: self.eventLoop)
+        } else {
+            let new = Application.GoogleCloudPlatform.GoogleCloudPubSubAPI(application: self.application, eventLoop: self.eventLoop).client
+            application.storage[GoogleCloudPubSubKey.self] = new
+            return new
+        }
+    }
+}

Sources/CloudPubSub/README.md

@@ -0,0 +1,64 @@
+#  GoogleCloudPubSubAPI
+
+## Getting Started
+If you only need to use the [Google Cloud PubSub API](https://cloud.google.com/pubsub), then this guide will help you get started.
+
+In your `Package.swift` file, make sure you have the following dependencies and targets
+
+```swift
+dependencies: [
+        //...
+        .package(url: "https://github.com/vapor-community/google-cloud.git", from: "1.0.0"),
+    ],
+    targets: [
+        .target(name: "MyAppName", dependencies: [
+            //...
+            .product(name: "CloudPubSub", package: "google-cloud"),
+        ]),
+    ]
+```
+
+Now you can setup the configuration for any GCP API globally via `Application`.
+
+In `configure.swift`
+
+```swift
+import CloudPubSub
+
+ app.googleCloud.credentials = try GoogleCloudCredentialsConfiguration(projectId: "myprojectid-12345",
+ credentialsFile: "~/path/to/service-account.json")
+```
+Next we setup the CloudlPubSub API configuration (specific to this API).
+
+```swift
+app.googleCloud.pubsub.configuration = .default()
+```
+
+Now we can start using the GoogleCloudPubSub API
+There's a handy extension on `Request` that you can use to get access to a pubsub client via a property named `gcPubsub`. 
+
+```swift
+func publishMessage(_ req: Request) throws -> EventLoopFuture<[String]> {
+    guard let topicId = req.parameters.get("topicId") else {
+        throw Abort(.badRequest, reason:"Missing Topic ID from the request")
+    }
+
+    try PubSubMessage.validate(content: req)
+    let message = try req.content.decode(PubSubMessage.self)
+
+    return req.gcPubSub.pubSubTopic.publish(topicId: topicId,
+                                            data: message.data,
+                                            attributes: nil,
+                                            orderingKey: nil)
+        .map { response in
+            return response.messageIds
+    }
+}
+
+struct PubSubMessage: Content {
+    let data: String
+    let attributes: [String: String]?
+    let orderingKey: String?
+}
+```
+