com.microsoft.ml.spark.core.env.NativeLoader Maven / Gradle / Ivy
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// Copyright (C) Microsoft Corporation. All rights reserved.
// Licensed under the MIT License. See LICENSE in project root for information.
package com.microsoft.ml.spark.core.env;
import java.io.*;
import java.nio.file.Files;
/**
* A helper class for loading native libraries from Java
*
* Some Java interfaces depend on native libraries that need to be loaded at runtime.
* This class is a simple utility that can load the native libraries from a jar in one of two ways:
*
*
* - By name: If a particular native library is needed, it will extract it to a temp folder
* (along with its dependencies) and load it from there.
* - All libraries: all libraries will be extracted to a temp folder and the libraries in the
* load manifest are loaded in the order provided, or loaded in the order specified in the
* native manifest if no load manifest is provided.
*
*
* The jar with the native libraries must contain a file name 'NATIVE_MANIFEST' that lists
* all native files (one per line, full name) to be extracted. If the loadAll() method is used,
* the libraries will be loaded in the order specified in the manifest. The native libraries should be
* in folders describing the OS they run on: linux, windows, mac.
* */
public class NativeLoader implements Serializable {
private String resourcesPath;
private Boolean extractionDone = false;
private File tempDir;
public NativeLoader(String topLevelResourcesPath) throws IOException {
this.resourcesPath = getResourcesPath(topLevelResourcesPath);
tempDir = Files.createTempDirectory("mml-natives").toFile();
tempDir.deleteOnExit();
}
/**
* Loads a named native library from the jar file
*
* This method will first try to load the library from java.library.path system property.
* Only if that fails, the named native library and its dependencies will be extracted to
* a temporary folder and loaded from there.
* */
public void loadLibraryByName(String libName) {
try {
// First try loading by name
// It's possible that the native library is already on a path java can discover
System.loadLibrary(libName);
}
catch (UnsatisfiedLinkError e) {
try {
// Get the OS specific library name
libName = System.mapLibraryName(libName);
extractNativeLibraries(libName);
// Try to load library from extracted native resources
System.load(tempDir.getAbsolutePath() + File.separator + libName);
}
catch (Exception ee) {
throw new UnsatisfiedLinkError(String.format(
"Could not load the native libraries because " +
"we encountered the following problems: %s and %s",
e.getMessage(), ee.getMessage()));
}
}
}
public static String getOSPrefix() {
String OS = System.getProperty("os.name").toLowerCase();
if (OS.contains("linux") || OS.contains("mac") || OS.contains("darwin")) {
return "";
} else if (OS.contains("windows")) {
return "lib";
} else {
throw new UnsatisfiedLinkError(
String.format("This component doesn't currently have native support for OS: %s", OS)
);
}
}
private void extractNativeLibraries(String libName) throws IOException {
if (!extractionDone) {
extractResourceFromPath(libName, resourcesPath);
}
extractionDone = true;
}
private static String getResourcesPath(String topLevelResourcesPath) {
String sep = "/";
String OS = System.getProperty("os.name").toLowerCase();
String resourcePrefix = topLevelResourcesPath + sep + "%s" + sep;
if (OS.contains("linux")) {
return String.format(resourcePrefix, "linux/x86_64");
} else if (OS.contains("windows")) {
return String.format(resourcePrefix, "windows/x86_64");
} else if (OS.contains("mac") || OS.contains("darwin")) {
return String.format(resourcePrefix, "osx/x86_64");
} else {
throw new UnsatisfiedLinkError(
String.format("This component doesn't currently have native support for OS: %s", OS)
);
}
}
private void extractResourceFromPath(String libName, String prefix) throws IOException {
File temp = new File(tempDir.getPath() + File.separator + libName);
temp.createNewFile();
temp.deleteOnExit();
if (!temp.exists()) {
throw new FileNotFoundException(String.format(
"Temporary file %s could not be created. Make sure you can write to this location.",
temp.getAbsolutePath())
);
}
String path = prefix + libName;
InputStream inStream = NativeLoader.class.getResourceAsStream(path);
if (inStream == null) {
throw new FileNotFoundException(String.format("Could not find resource %s in jar.", path));
}
FileOutputStream outStream = new FileOutputStream(temp);
byte[] buffer = new byte[1 << 18];
int bytesRead;
try {
while ((bytesRead = inStream.read(buffer)) >= 0) {
outStream.write(buffer, 0, bytesRead);
}
} finally {
outStream.close();
inStream.close();
}
}
}