Update authentication and metrics logging

Package.swift

@@ -8,7 +8,7 @@ let package = Package(
     ],
     dependencies: [
         .package(url: "https://github.com/vapor/vapor", from: "4.0.0"),
-        .package(url: "https://github.com/christophhagen/Clairvoyant", from: "0.2.0"),
+        .package(url: "https://github.com/christophhagen/Clairvoyant", branch: "main"),
     ],
     targets: [
         .target(name: "App",

Sources/App/Authenticator.swift

@@ -0,0 +1,39 @@
+import Foundation
+import Clairvoyant
+import Vapor
+
+final class Authenticator: MetricAccessAuthenticator {
+
+    private var writers: Set<String>
+
+    init(writers: [String]) {
+        self.writers = Set(writers)
+    }
+
+
+    func hasAuthorization(for key: String) -> Bool {
+        // Note: This is not a constant-time compare, so there may be an opportunity
+        // for timing attack here. Sets perform hashed lookups, so this may be less of an issue,
+        // and we're not doing anything critical in this application.
+        // Worst case, an unauthorized person with a lot of free time and energy to hack this system
+        // is able to change contents of the database, which are backed up in any case.
+        writers.contains(key)
+    }
+
+    func metricAccess(isAllowedForToken accessToken: Data) -> Bool {
+        guard let key = String(data: accessToken, encoding: .utf8) else {
+            return false
+        }
+        return hasAuthorization(for: key)
+    }
+
+
+    func authorize(_ request: Request) throws {
+        guard let key = request.headers.first(name: "key") else {
+            throw Abort(.badRequest) // 400
+        }
+        guard hasAuthorization(for: key) else {
+            throw Abort(.forbidden) // 403
+        }
+    }
+}

Sources/App/CapServer+Routes.swift

@@ -0,0 +1,141 @@
+import Vapor
+import Foundation
+
+/// The decoder to extract caps from JSON payloads given to the `cap` route.
+private let decoder = JSONDecoder()
+
+/// The date formatter to decode dates in requests
+private let dateFormatter: DateFormatter = {
+    let df = DateFormatter()
+    df.dateFormat = "yy-MM-dd-HH-mm-ss"
+    return df
+}()
+
+extension CapServer {
+
+    private func ensureOperability() throws {
+        guard isOperational else {
+            throw Abort(.noContent)
+        }
+    }
+
+    func registerRoutes(with app: Application, authenticator: Authenticator) {
+        app.get("version") { _ in
+            try self.ensureOperability()
+            return "\(self.classifierVersion)"
+        }
+
+        // Add or change a cap
+        app.postCatching("cap") { request in
+            try self.ensureOperability()
+            try authenticator.authorize(request)
+            let data = try request.getBodyData()
+            let cap = try decoder.decode(Cap.self, from: data)
+            try self.addOrUpdate(cap)
+        }
+
+        // Upload an image
+        app.postCatching("images", ":n") { request in
+            try self.ensureOperability()
+            try authenticator.authorize(request)
+            guard let cap = request.parameters.get("n", as: Int.self) else {
+                log("Invalid parameter for cap")
+                throw Abort(.badRequest)
+            }
+            let data = try request.getBodyData()
+            try self.save(image: data, for: cap)
+        }
+        // Update the classifier
+        app.on(.POST, "classifier", ":version", body: .collect(maxSize: "50mb")) { request -> HTTPStatus in
+            guard let version = request.parameters.get("version", as: Int.self) else {
+                log("Invalid parameter for version")
+                throw Abort(.badRequest)
+            }
+            guard version > self.classifierVersion else {
+                throw Abort(.alreadyReported) // 208
+            }
+
+            try self.ensureOperability()
+            try authenticator.authorize(request)
+            let data = try request.getBodyData()
+            try self.save(classifier: data, version: version)
+            return .ok
+        }
+
+        // Update the trained classes
+        app.postCatching("classes", ":date") { request in
+            guard let dateString = request.parameters.get("date") else {
+                log("Invalid parameter for date")
+                throw Abort(.badRequest)
+            }
+            guard let date = dateFormatter.date(from: dateString) else {
+                log("Invalid date specification")
+                throw Abort(.badRequest)
+            }
+
+            try self.ensureOperability()
+            try authenticator.authorize(request)
+            let body = try request.getStringBody()
+
+            self.updateTrainedClasses(content: body)
+            self.removeAllEntriesInImageChangeList(before: date)
+        }
+
+        // Get the list of missing thumbnails
+        app.get("thumbnails", "missing") { request in
+            try self.ensureOperability()
+            let missingThumbnails = self.getListOfMissingThumbnails()
+            return missingThumbnails.map(String.init).joined(separator: ",")
+        }
+
+        // Upload the thumbnail of a cap
+        app.postCatching("thumbnails", ":cap") { request in
+            guard let cap = request.parameters.get("cap", as: Int.self) else {
+                log("Invalid cap parameter for thumbnail upload")
+                throw Abort(.badRequest)
+            }
+            try self.ensureOperability()
+            try authenticator.authorize(request)
+            let data = try request.getBodyData()
+            self.saveThumbnail(data, for: cap)
+        }
+
+        // Delete the image of a cap
+        app.postCatching("delete", ":cap", ":version") { request in
+            guard let cap = request.parameters.get("cap", as: Int.self) else {
+                log("Invalid cap parameter for image deletion")
+                throw Abort(.badRequest)
+            }
+            guard let version = request.parameters.get("version", as: Int.self) else {
+                log("Invalid version parameter for image deletion")
+                throw Abort(.badRequest)
+            }
+
+            try self.ensureOperability()
+            try authenticator.authorize(request)
+            guard self.deleteImage(version: version, for: cap) else {
+                throw Abort(.gone)
+            }
+        }
+    }
+}
+
+private extension Request {
+
+    func getBodyData() throws -> Data {
+        guard let buffer = body.data else {
+            log("Missing body data")
+            throw CapError.invalidBody
+        }
+        return Data(buffer: buffer)
+    }
+
+    func getStringBody() throws -> String {
+        let data = try getBodyData()
+        guard let content = String(data: data, encoding: .utf8) else {
+            log("Invalid string body")
+            throw CapError.invalidBody
+        }
+        return content
+    }
+}

Sources/App/CapServer.swift

@@ -2,7 +2,7 @@ import Foundation
 import Vapor
 import Clairvoyant
 
-final class CapServer: ServerOwner {
+final class CapServer {
     
     // MARK: Paths
     
@@ -28,10 +28,12 @@ final class CapServer: ServerOwner {
     private let fm = FileManager.default
     
     private let changedImageEntryDateFormatter: DateFormatter
+
+    /// Indicates that the data is loaded
+    private(set) var isOperational = false
     
     // MARK: Caps
 
-    private var writers: Set<String>
     
     /// The changed images not yet written to disk
     private var unwrittenImageChanges: [(cap: Int, image: Int)] = []
@@ -39,7 +41,7 @@ final class CapServer: ServerOwner {
     var classifierVersion: Int = 0 {
         didSet {
             writeClassifierVersion()
-            updateMonitoredClassifierVersionProperty()
+            classifierMetric.update(classifierVersion)
         }
     }
 
@@ -60,7 +62,8 @@ final class CapServer: ServerOwner {
     private var caps = [Int: Cap]() {
         didSet {
             scheduleSave()
-            updateMonitoredPropertiesOnCapChange()
+            capCountMetric.update(caps.count)
+            imageCountMetric.update(imageCount)
         }
     }
 
@@ -76,7 +79,7 @@ final class CapServer: ServerOwner {
         caps.reduce(0) { $0 + $1.value.count }
     }
 
-    init(in folder: URL, writers: [String]) {
+    init(in folder: URL) {
         self.imageFolder = folder.appendingPathComponent("images")
         self.thumbnailFolder = folder.appendingPathComponent("thumbnails")
         self.gridCountFile = folder.appendingPathComponent("count.js")
@@ -85,7 +88,6 @@ final class CapServer: ServerOwner {
         self.classifierVersionFile = folder.appendingPathComponent("classifier.version")
         self.classifierFile = folder.appendingPathComponent("classifier.mlmodel")
         self.changedImagesFile = folder.appendingPathComponent("changes.txt")
-        self.writers = Set(writers)
         self.changedImageEntryDateFormatter = DateFormatter()
         changedImageEntryDateFormatter.dateFormat = "yy-MM-dd-HH-mm-ss"
     }
@@ -97,6 +99,7 @@ final class CapServer: ServerOwner {
         updateGridCapCount()
         try ensureExistenceOfChangedImagesFile()
         organizeImages()
+        isOperational = true
     }
 
     private func loadClassifierVersion(at url: URL) {
@@ -234,17 +237,6 @@ final class CapServer: ServerOwner {
         folder(of: cap).appendingPathComponent(String(format: "%04d-%02d.jpg", cap, version))
     }
 
-    // MARK: Authentication
-
-    func hasAuthorization(for key: String) -> Bool {
-        // Note: This is not a constant-time compare, so there may be an opportunity
-        // for timing attack here. Sets perform hashed lookups, so this may be less of an issue,
-        // and we're not doing anything critical in this application.
-        // Worst case, an unauthorized person with a lot of free time and energy to hack this system
-        // is able to change contents of the database, which are backed up in any case.
-        writers.contains(key)
-    }
-    
     // MARK: Counts
 
     private func images(in folder: URL) throws -> [URL] {
@@ -466,82 +458,11 @@ final class CapServer: ServerOwner {
         }
     }
 
-    // MARK: ServerOwner
-
-    let authenticationMethod: PropertyAuthenticationMethod = .accessToken
-
-    func hasReadPermission(for property: UInt32, accessData: Data) -> Bool {
-        guard let key = String(data: accessData, encoding: .utf8) else {
-            return false
-        }
-        return writers.contains(key)
-    }
-
-    func hasWritePermission(for property: UInt32, accessData: Data) -> Bool {
-        guard let key = String(data: accessData, encoding: .utf8) else {
-            return false
-        }
-        return writers.contains(key)
-    }
-
-    func hasListAccessPermission(_ accessData: Data) -> Bool {
-        guard let key = String(data: accessData, encoding: .utf8) else {
-            return false
-        }
-        return writers.contains(key)
-    }
-
     // MARK: Monitoring
 
-    public let name = "caps"
+    private let capCountMetric = Metric<Int>("caps.count")
 
-    private let capCountPropertyId = PropertyId(owner: "caps", uniqueId: 2)
+    private let imageCountMetric = Metric<Int>("caps.images")
 
-    private let imageCountPropertyId = PropertyId(owner: "caps", uniqueId: 3)
+    private let classifierMetric = Metric<Int>("caps.classifier")
-
-    private let classifierVersionPropertyId = PropertyId(owner: "caps", uniqueId: 4)
-
-    func registerProperties(with monitor: PropertyManager) {
-        let capCountProperty = PropertyRegistration(
-            uniqueId: capCountPropertyId.uniqueId,
-            name: "caps",
-            updates: .continuous,
-            isLogged: true,
-            allowsManualUpdate: false,
-            read: { [weak self] in
-                return (self?.capCount ?? 0).timestamped()
-            })
-        monitor.register(capCountProperty, for: self)
-
-        let imageCountProperty = PropertyRegistration(
-            uniqueId: imageCountPropertyId.uniqueId,
-            name: "images",
-            updates: .continuous,
-            isLogged: true,
-            allowsManualUpdate: false,
-            read: { [weak self] in
-                return (self?.imageCount ?? 0).timestamped()
-            })
-        monitor.register(imageCountProperty, for: self)
-
-        let classifierVersionProperty = PropertyRegistration(
-            uniqueId: classifierVersionPropertyId.uniqueId,
-            name: "classifier",
-            updates: .continuous,
-            isLogged: true,
-            allowsManualUpdate: false,
-            read: { [weak self] in
-                return (self?.classifierVersion ?? 0).timestamped()
-            })
-        monitor.register(classifierVersionProperty, for: self)
-    }
-
-    private func updateMonitoredPropertiesOnCapChange() {
-        try? monitor.logChanged(property: capCountPropertyId, value: capCount.timestamped())
-        try? monitor.logChanged(property: imageCountPropertyId, value: imageCount.timestamped())
-    }
-
-    private func updateMonitoredClassifierVersionProperty() {
-        try? monitor.logChanged(property: classifierVersionPropertyId, value: classifierVersion.timestamped())
-    }
 }

Sources/App/Error.swift

@@ -45,6 +45,13 @@ enum CapError: Error {
      HTTP Code: 406
      */
     case invalidData
+
+    /**
+     The server failed to initialize the data and is not operational
+
+     HTTP Code: 204
+     */
+    case serviceUnavailable
     
     var response: HTTPResponseStatus {
         switch self {
@@ -60,6 +67,7 @@ enum CapError: Error {
         case .invalidFile: return .preconditionFailed
         /// 500
         case .invalidConfiguration: return .internalServerError
+        case .serviceUnavailable: return .noContent
         }
     }
 }

Sources/App/configure.swift

@@ -2,24 +2,27 @@ import Vapor
 import Foundation
 import Clairvoyant
 
-
-private(set) var server: CapServer!
-private(set) var monitor: PropertyManager!
-
 public func configure(_ app: Application) throws {
 
     let resourceDirectory = URL(fileURLWithPath: app.directory.resourcesDirectory)
     let publicDirectory = app.directory.publicDirectory
 
     let config = Config(loadFrom: resourceDirectory)
+    let authenticator = Authenticator(writers: config.writers)
 
-    server = CapServer(in: URL(fileURLWithPath: publicDirectory),
+    let monitor =  MetricObserver(
-                       writers: config.writers)
+        logFolder: config.logURL,
+        authenticator: authenticator,
+        logMetricId: "caps.log")
 
-    monitor = .init(logFolder: config.logURL, serverOwner: server)
+    // All new metrics are automatically registered with the standard observer
-    monitor.update(status: .initializing)
+    MetricObserver.standard = monitor
+
+    let status = Metric<ServerStatus>("caps.status")
+    status.update(.initializing)
+
+    let server = CapServer(in: URL(fileURLWithPath: publicDirectory))
 
-    server.registerProperties(with: monitor)
     monitor.registerRoutes(app)
 
     app.http.server.configuration.port = config.port
@@ -30,20 +33,19 @@ public func configure(_ app: Application) throws {
         app.middleware.use(middleware)
     }
 
+    // Register routes to the router
+    server.registerRoutes(with: app, authenticator: authenticator)
+
+    // Initialize the server data
     do {
         try server.loadData()
+        status.update(.nominal)
     } catch {
-        monitor.update(status: .initializationFailure)
+        status.update(.initializationFailure)
-        return
     }
-
-    // Register routes to the router
-    routes(app)
-
-    monitor.update(status: .nominal)
 }
 
 func log(_ message: String) {
-    monitor.log(message)
+    MetricObserver.standard?.log(message)
     print(message)
 }

Sources/App/routes.swift

@@ -1,133 +0,0 @@
-import Vapor
-import Foundation
-
-/// The decoder to extract caps from JSON payloads given to the `cap` route.
-private let decoder = JSONDecoder()
-
-/// The date formatter to decode dates in requests
-private let dateFormatter: DateFormatter = {
-    let df = DateFormatter()
-    df.dateFormat = "yy-MM-dd-HH-mm-ss"
-    return df
-}()
-
-private func authorize(_ request: Request) throws {
-    guard let key = request.headers.first(name: "key") else {
-        throw Abort(.badRequest) // 400
-    }
-    guard server.hasAuthorization(for: key) else {
-        throw Abort(.forbidden) // 403
-    }
-}
-
-func routes(_ app: Application) {
-    
-    app.get("version") { _ in
-        "\(server.classifierVersion)"
-    }
-
-    // Add or change a cap
-    app.postCatching("cap") { request in
-        try authorize(request)
-        let data = try request.getBodyData()
-        let cap = try decoder.decode(Cap.self, from: data)
-        try server.addOrUpdate(cap)
-    }
-    
-    // Upload an image
-    app.postCatching("images", ":n") { request in
-        try authorize(request)
-        guard let cap = request.parameters.get("n", as: Int.self) else {
-            log("Invalid parameter for cap")
-            throw Abort(.badRequest)
-        }
-        let data = try request.getBodyData()
-        try server.save(image: data, for: cap)
-    }
-    
-    // Update the classifier
-    app.on(.POST, "classifier", ":version", body: .collect(maxSize: "50mb")) { request -> HTTPStatus in
-        try authorize(request)
-        guard let version = request.parameters.get("version", as: Int.self) else {
-            log("Invalid parameter for version")
-            throw Abort(.badRequest)
-        }
-        guard version > server.classifierVersion else {
-            throw Abort(.alreadyReported) // 208
-        }
-        let data = try request.getBodyData()
-        try server.save(classifier: data, version: version)
-        return .ok
-    }
-    
-    // Update the trained classes
-    app.postCatching("classes", ":date") { request in
-        guard let dateString = request.parameters.get("date") else {
-            log("Invalid parameter for date")
-            throw Abort(.badRequest)
-        }
-        guard let date = dateFormatter.date(from: dateString) else {
-            log("Invalid date specification")
-            throw Abort(.badRequest)
-        }
-        
-        try authorize(request)
-        let body = try request.getStringBody()
-        
-        server.updateTrainedClasses(content: body)
-        server.removeAllEntriesInImageChangeList(before: date)
-    }
-    
-    // Get the list of missing thumbnails
-    app.get("thumbnails", "missing") { request in
-        let missingThumbnails = server.getListOfMissingThumbnails()
-        return missingThumbnails.map(String.init).joined(separator: ",")
-    }
-    
-    // Upload the thumbnail of a cap
-    app.postCatching("thumbnails", ":cap") { request in
-        guard let cap = request.parameters.get("cap", as: Int.self) else {
-            log("Invalid cap parameter for thumbnail upload")
-            throw Abort(.badRequest)
-        }
-        try authorize(request)
-        let data = try request.getBodyData()
-        server.saveThumbnail(data, for: cap)
-    }
-    
-    // Delete the image of a cap
-    app.postCatching("delete", ":cap", ":version") { request in
-        guard let cap = request.parameters.get("cap", as: Int.self) else {
-            log("Invalid cap parameter for image deletion")
-            throw Abort(.badRequest)
-        }
-        try authorize(request)
-        guard let version = request.parameters.get("version", as: Int.self) else {
-            log("Invalid version parameter for image deletion")
-            throw Abort(.badRequest)
-        }
-        guard server.deleteImage(version: version, for: cap) else {
-            throw Abort(.gone)
-        }
-    }
-}
-
-private extension Request {
-    
-    func getBodyData() throws -> Data {
-        guard let buffer = body.data else {
-            log("Missing body data")
-            throw CapError.invalidBody
-        }
-        return Data(buffer: buffer)
-    }
-    
-    func getStringBody() throws -> String {
-        let data = try getBodyData()
-        guard let content = String(data: data, encoding: .utf8) else {
-            log("Invalid string body")
-            throw CapError.invalidBody
-        }
-        return content
-    }
-}