make logging optional and update docs

Author: nervenes

README.md

@@ -62,6 +62,8 @@ Furthermore, the group will setup signal listeners for the configured signals an
 on each service.
 
 ```swift
+import ServiceLifecycle
+
 actor FooService: Service {
     func run() async throws {
         print("FooService starting")
@@ -78,13 +80,12 @@ struct Application {
 
         let serviceGroup = ServiceGroup(
             services: [service1, service2],
-            configuration: .init(gracefulShutdownSignals: [.sigterm]),
-            logger: logger
+            gracefulShutdownSignals: [.sigterm]
         )
+        
         try await serviceGroup.run()
     }
 }
-
 ```
 
 ## Security

Sources/ServiceLifecycle/Docs.docc/How to adopt ServiceLifecycle in applications.md

@@ -77,13 +77,7 @@ struct Application {
 
     let serviceGroup = ServiceGroup(
       // We are encoding the dependency hierarchy here by listing the fooService first
-      configuration: .init(
-        services: [
-          .init(service: fooService),
-          .init(service: barService)
-        ],
-        logger: logger
-      ),
+      services: [fooService, barService]
     )
 
     try await serviceGroup.run()
@@ -148,11 +142,8 @@ struct Application {
     })
 
     let serviceGroup = ServiceGroup(
-      configuration: .init(
-        services: [.init(service: streamingService)],
-        gracefulShutdownSignals: [.sigterm],
-        logger: logger
-      )
+      services: [streamingService],
+      gracefulShutdownSignals: [.sigterm]
     )
 
     try await serviceGroup.run()
@@ -210,11 +201,8 @@ struct Application {
     })
 
     let serviceGroup = ServiceGroup(
-      configuration: .init(
-        services: [.init(service: streamingService)],
-        gracefulShutdownSignals: [.sigterm],
-        logger: logger
-      )
+      services: [streamingService],
+      gracefulShutdownSignals: [.sigterm]
     )
 
     try await serviceGroup.run()
@@ -266,8 +254,7 @@ struct Application {
             successTerminationBehavior: .shutdownGracefully,
             failureTerminationBehavior: .shutdownGracefully
           )
-        ],
-        logger: logger
+        ]
       ),
     )
 

Sources/ServiceLifecycle/ServiceGroup.swift

@@ -76,19 +76,23 @@ public actor ServiceGroup: Sendable, Service {
         services: [any Service],
         gracefulShutdownSignals: [UnixSignal] = [],
         cancellationSignals: [UnixSignal] = [],
-        logger: Logger
+        logger: Logger? = nil
     ) {
+        if logger == nil {
+            LoggingSystem.bootstrap { SwiftLogNoOpLogHandler($0) }
+        }
+        
         let configuration = ServiceGroupConfiguration(
             services: services.map { ServiceGroupConfiguration.ServiceConfiguration(service: $0) },
             gracefulShutdownSignals: gracefulShutdownSignals,
             cancellationSignals: cancellationSignals,
-            logger: logger
+            logger: logger ?? .init(label: "")
         )
 
         self.init(configuration: configuration)
     }
 
-    @available(*, deprecated)
+    @available(*, deprecated, renamed: "init(services:gracefulShutdownSignals:cancellationSignals:logger:)")
     public init(
         services: [any Service],
         configuration: ServiceGroupConfiguration,

Sources/ServiceLifecycle/ServiceGroupConfiguration.swift

@@ -172,10 +172,14 @@ public struct ServiceGroupConfiguration: Sendable {
     ///   - logger: The group's logger.
     public init(
         services: [ServiceConfiguration],
-        logger: Logger
+        logger: Logger? = nil
     ) {
+        if logger == nil {
+            LoggingSystem.bootstrap { SwiftLogNoOpLogHandler($0) }
+        }
+        
         self.services = services
-        self.logger = logger
+        self.logger = logger ?? .init(label: "")
     }
 
     /// Initializes a new ``ServiceGroupConfiguration``.
@@ -189,10 +193,14 @@ public struct ServiceGroupConfiguration: Sendable {
         services: [ServiceConfiguration],
         gracefulShutdownSignals: [UnixSignal] = [],
         cancellationSignals: [UnixSignal] = [],
-        logger: Logger
+        logger: Logger? = nil
     ) {
+        if logger == nil {
+            LoggingSystem.bootstrap { SwiftLogNoOpLogHandler($0) }
+        }
+        
         self.services = services
-        self.logger = logger
+        self.logger = logger ?? .init(label: "")
         self.gracefulShutdownSignals = gracefulShutdownSignals
         self.cancellationSignals = cancellationSignals
     }
@@ -204,10 +212,14 @@ public struct ServiceGroupConfiguration: Sendable {
     ///   - logger: The group's logger.
     public init(
         services: [Service],
-        logger: Logger
+        logger: Logger? = nil
     ) {
+        if logger == nil {
+            LoggingSystem.bootstrap { SwiftLogNoOpLogHandler($0) }
+        }
+        
         self.services = Array(services.map { ServiceConfiguration(service: $0) })
-        self.logger = logger
+        self.logger = logger ?? .init(label: "")
     }
 
     /// Initializes a new ``ServiceGroupConfiguration``.
@@ -221,10 +233,14 @@ public struct ServiceGroupConfiguration: Sendable {
         services: [Service],
         gracefulShutdownSignals: [UnixSignal] = [],
         cancellationSignals: [UnixSignal] = [],
-        logger: Logger
+        logger: Logger? = nil
     ) {
+        if logger == nil {
+            LoggingSystem.bootstrap { SwiftLogNoOpLogHandler($0) }
+        }
+        
         self.services = Array(services.map { ServiceConfiguration(service: $0) })
-        self.logger = logger
+        self.logger = logger ?? .init(label: "")
         self.gracefulShutdownSignals = gracefulShutdownSignals
         self.cancellationSignals = cancellationSignals
     }