Use stderr for logging messages (#228)

* Use stderr for logging messages

* Rename printerr into printError

Author: shabalind

Benchmarks/main.swift

@@ -13,6 +13,7 @@
 // limitations under the License.
 
 import Commander
+import ModelSupport
 
 func runBenchmark(
     _ name: String,
@@ -42,8 +43,8 @@ func runBenchmark(
             benchmark: bench,
             callback: logResults)
     } else {
-        print("No registered inference benchmark with a name: \(name)")
-        print("Consider running `list` command to see all available benchmarks.")
+        printError("No registered inference benchmark with a name: \(name)")
+        printError("Consider running `list` command to see all available benchmarks.")
     }
 }
 
@@ -98,11 +99,11 @@ let main =
                 iterations: iterations,
                 epochs: epochs)
             if !trainingFlag && !inferenceFlag {
-                print("Must specify either --training xor --inference benchmark variety.")
+                printError("Must specify either --training xor --inference benchmark variety.")
             } else if trainingFlag && inferenceFlag {
-                print("Can't specify both --training and --inference benchmark variety.")
+                printError("Can't specify both --training and --inference benchmark variety.")
             } else if name == "" {
-                print("Must provide a --benchmark to run.")
+                printError("Must provide a --benchmark to run.")
             } else {
                 var variety: BenchmarkVariety
                 if trainingFlag {

Datasets/CIFAR10/CIFAR10.swift

@@ -18,6 +18,7 @@
 // https://www.cs.toronto.edu/~kriz/cifar.html
 
 import Foundation
+import ModelSupport
 import TensorFlow
 
 #if canImport(FoundationNetworking)
@@ -41,23 +42,23 @@ func downloadCIFAR10IfNotPresent(to directory: String = ".") {
 
     guard !directoryExists else { return }
 
-    print("Downloading CIFAR dataset...")
+    printError("Downloading CIFAR dataset...")
     let archivePath = "\(directory)/cifar-10-binary.tar.gz"
     let archiveExists = FileManager.default.fileExists(atPath: archivePath)
     if !archiveExists {
-        print("Archive missing, downloading...")
+        printError("Archive missing, downloading...")
         do {
             let downloadedFile = try Data(
                 contentsOf: URL(
                     string: "https://www.cs.toronto.edu/~kriz/cifar-10-binary.tar.gz")!)
             try downloadedFile.write(to: URL(fileURLWithPath: archivePath))
         } catch {
-            print("Could not download CIFAR dataset, error: \(error)")
+            printError("Could not download CIFAR dataset, error: \(error)")
             exit(-1)
         }
     }
 
-    print("Archive downloaded, processing...")
+    printError("Archive downloaded, processing...")
 
     #if os(macOS)
         let tarLocation = "/usr/bin/tar"
@@ -72,17 +73,17 @@ func downloadCIFAR10IfNotPresent(to directory: String = ".") {
         try task.run()
         task.waitUntilExit()
     } catch {
-        print("CIFAR extraction failed with error: \(error)")
+        printError("CIFAR extraction failed with error: \(error)")
     }
 
     do {
         try FileManager.default.removeItem(atPath: archivePath)
     } catch {
-        print("Could not remove archive, error: \(error)")
+        printError("Could not remove archive, error: \(error)")
         exit(-1)
     }
 
-    print("Unarchiving completed")
+    printError("Unarchiving completed")
 }
 
 func loadCIFARFile(named name: String, in directory: String = ".") -> LabeledExample {
@@ -91,11 +92,11 @@ func loadCIFARFile(named name: String, in directory: String = ".") -> LabeledExa
 
     let imageCount = 10000
     guard let fileContents = try? Data(contentsOf: URL(fileURLWithPath: path)) else {
-        print("Could not read dataset file: \(name)")
+        printError("Could not read dataset file: \(name)")
         exit(-1)
     }
     guard fileContents.count == 30_730_000 else {
-        print(
+        printError(
             "Dataset file \(name) should have 30730000 bytes, instead had \(fileContents.count)")
         exit(-1)
     }

Datasets/DatasetUtilities.swift

@@ -13,6 +13,7 @@
 // limitations under the License.
 
 import Foundation
+import ModelSupport
 
 #if canImport(FoundationNetworking)
     import FoundationNetworking
@@ -27,7 +28,7 @@ public struct DatasetUtilities {
         remoteRoot: URL,
         localStorageDirectory: URL = currentWorkingDirectoryURL
     ) -> Data {
-        print("Loading resource: \(filename)")
+        printError("Loading resource: \(filename)")
 
         let resource = ResourceDefinition(
             filename: filename,
@@ -37,16 +38,16 @@ public struct DatasetUtilities {
         let localURL = resource.localURL
 
         if !FileManager.default.fileExists(atPath: localURL.path) {
-            print(
+            printError(
                 "File does not exist locally at expected path: \(localURL.path) and must be fetched"
             )
             fetchFromRemoteAndSave(resource)
         }
 
         do {
-            print("Loading local data at: \(localURL.path)")
+            printError("Loading local data at: \(localURL.path)")
             let data = try Data(contentsOf: localURL)
-            print("Succesfully loaded resource: \(filename)")
+            printError("Succesfully loaded resource: \(filename)")
             return data
         } catch {
             fatalError("Failed to contents of resource: \(localURL)")
@@ -76,20 +77,20 @@ public struct DatasetUtilities {
         let archiveLocation = resource.archiveURL
 
         do {
-            print("Fetching URL: \(remoteLocation)...")
+            printError("Fetching URL: \(remoteLocation)...")
             let archiveData = try Data(contentsOf: remoteLocation)
-            print("Writing fetched archive to: \(archiveLocation.path)")
+            printError("Writing fetched archive to: \(archiveLocation.path)")
             try archiveData.write(to: archiveLocation)
         } catch {
             fatalError("Failed to fetch and save resource with error: \(error)")
         }
-        print("Archive saved to: \(archiveLocation.path)")
+        printError("Archive saved to: \(archiveLocation.path)")
 
         extractArchive(for: resource)
     }
 
     static func extractArchive(for resource: ResourceDefinition) {
-        print("Extracting archive...")
+        printError("Extracting archive...")
 
         let archivePath = resource.archiveURL.path
 

Package.swift

@@ -25,7 +25,7 @@ let package = Package(
     ],
     targets: [
         .target(name: "ImageClassificationModels", path: "Models/ImageClassification"),
-        .target(name: "Datasets", path: "Datasets"),
+        .target(name: "Datasets", dependencies: ["ModelSupport"], path: "Datasets"),
         .target(name: "ModelSupport", path: "Support"),
         .target(
             name: "Autoencoder", dependencies: ["Datasets", "ModelSupport"], path: "Autoencoder"),

Support/Image.swift

@@ -81,10 +81,12 @@ public struct Image {
     }
 }
 
-public func saveImage(_ tensor: Tensor<Float>, size: (Int, Int), directory: String, name: String) throws {
+public func saveImage(_ tensor: Tensor<Float>, size: (Int, Int), directory: String, name: String)
+    throws
+{
     try createDirectoryIfMissing(at: directory)
     let reshapedTensor = tensor.reshaped(to: [size.0, size.1, 1])
     let image = Image(tensor: reshapedTensor)
-    let outputURL = URL(fileURLWithPath:"\(directory)\(name).jpg")
+    let outputURL = URL(fileURLWithPath: "\(directory)\(name).jpg")
     image.save(to: outputURL)
 }

Support/Stderr.swift

@@ -0,0 +1,14 @@
+import Foundation
+
+var stderr = FileHandle.standardError
+
+extension FileHandle: TextOutputStream {
+    public func write(_ string: String) {
+        guard let data = string.data(using: .utf8) else { return }
+        self.write(data)
+    }
+}
+
+public func printError(_ message: String) {
+    print(message, to: &stderr)
+}