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Handle providers of optional services in ubermodule classloader (#91217)
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* When scanning a jar bundle for services to add to the
ubermodule descriptor, we must make sure that any optional
dependencies match up to services that are defined in the
code. If we naively declare that our module uses any service
that is implemented by one of its jars, we might fail to load
the plugin because the original implementation is not included
in our bundle.

Here we add a fairly detailed test scenario for required and
optional services defined outside the bundle, as well as for
services defined within the bundle, either by module declaration
or by META-INF/services entry.
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@williamrandolph
williamrandolph committed Nov 15, 2022
1 parent 143828e commit e144722
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Showing 3 changed files with 408 additions and 36 deletions.
52 changes: 37 additions & 15 deletions server/src/main/java/org/elasticsearch/plugins/ModuleSupport.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -45,27 +45,41 @@ private ModuleSupport() {
throw new AssertionError("Utility class, should not be instantiated");
}

static ModuleFinder ofSyntheticPluginModule(String name, Path[] jarPaths, Set<String> requires, Set<String> uses) {
static ModuleFinder ofSyntheticPluginModule(
String name,
Path[] jarPaths,
Set<String> requires,
Set<String> uses,
Predicate<String> isPackageInParentLayers
) {
try {
return new InMemoryModuleFinder(
new InMemoryModuleReference(createModuleDescriptor(name, jarPaths, requires, uses), URI.create("module:/" + name))
new InMemoryModuleReference(
createModuleDescriptor(name, jarPaths, requires, uses, isPackageInParentLayers),
URI.create("module:/" + name)
)
);
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}

@SuppressForbidden(reason = "need access to the jar file")
static ModuleDescriptor createModuleDescriptor(String name, Path[] jarPaths, Set<String> requires, Set<String> uses)
throws IOException {
static ModuleDescriptor createModuleDescriptor(
String name,
Path[] jarPaths,
Set<String> requires,
Set<String> uses,
Predicate<String> isPackageInParentLayers
) throws IOException {
var builder = ModuleDescriptor.newOpenModule(name); // open module, for now
requires.stream().forEach(builder::requires);
uses.stream().forEach(builder::uses);

// scan the names of the entries in the JARs
Set<String> pkgs = new HashSet<>();
Map<String, List<String>> allBundledProviders = new HashMap<>();
Set<String> allBundledServices = new HashSet<>();
Set<String> servicesUsedInBundle = new HashSet<>();
for (Path path : jarPaths) {
assert path.getFileName().toString().endsWith(".jar") : "expected jars suffix, in path: " + path;
try (JarFile jf = new JarFile(path.toFile(), true, ZipFile.OPEN_READ, Runtime.version())) {
Expand All @@ -74,13 +88,13 @@ static ModuleDescriptor createModuleDescriptor(String name, Path[] jarPaths, Set
if (moduleInfo != null) {
var descriptor = getDescriptorForModularJar(path);
pkgs.addAll(descriptor.packages());
allBundledServices.addAll(descriptor.uses());
servicesUsedInBundle.addAll(descriptor.uses());
for (ModuleDescriptor.Provides p : descriptor.provides()) {
String serviceName = p.service();
List<String> providersInModule = p.providers();

allBundledProviders.compute(serviceName, (k, v) -> createListOrAppend(v, providersInModule));
allBundledServices.add(serviceName);
servicesUsedInBundle.add(serviceName);
}
} else {
var scan = scan(jf);
Expand All @@ -92,21 +106,29 @@ static ModuleDescriptor createModuleDescriptor(String name, Path[] jarPaths, Set
List<String> providersInJar = getProvidersFromServiceFile(jf, serviceFileName);

allBundledProviders.compute(serviceName, (k, v) -> createListOrAppend(v, providersInJar));
allBundledServices.add(serviceName);
servicesUsedInBundle.add(serviceName);
}
}
}
}

builder.packages(pkgs);

// the module needs to use all services it provides, for the case of internal use
allBundledServices.addAll(allBundledProviders.keySet());
// but we don't want to add any services we already got from the parent layer
allBundledServices.removeAll(uses);
// we don't want to add any services we already got from the parent layer
servicesUsedInBundle.removeAll(uses);

allBundledServices.forEach(builder::uses);
allBundledProviders.forEach(builder::provides);
// Services that aren't exported in the parent layer or defined in our
// bundle. This can happen for optional (compile-time) dependencies
Set<String> missingServices = servicesUsedInBundle.stream()
.filter(s -> isPackageInParentLayers.test(toPackageName(s, ".").orElseThrow()) == false)
.filter(s -> pkgs.contains(toPackageName(s, ".").orElseThrow()) == false)
.collect(Collectors.toSet());

servicesUsedInBundle.stream().filter(s -> missingServices.contains(s) == false).forEach(builder::uses);
allBundledProviders.entrySet()
.stream()
.filter(e -> missingServices.contains(e.getKey()) == false)
.forEach(e -> builder.provides(e.getKey(), e.getValue()));
return builder.build();
}

Expand Down Expand Up @@ -246,7 +268,7 @@ static boolean isJavaPlatformModule(ModuleDescriptor md) {
@SuppressForbidden(reason = "need access to the jar file")
private static List<String> getProvidersFromServiceFile(JarFile jf, String sf) throws IOException {
try (BufferedReader bf = new BufferedReader(new InputStreamReader(jf.getInputStream(jf.getEntry(sf)), StandardCharsets.UTF_8))) {
return bf.lines().toList();
return bf.lines().filter(Predicate.not(l -> l.startsWith("#"))).filter(Predicate.not(String::isEmpty)).toList();
}
}

Expand Down
50 changes: 33 additions & 17 deletions server/src/main/java/org/elasticsearch/plugins/UberModuleClassLoader.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -57,21 +57,16 @@ public class UberModuleClassLoader extends SecureClassLoader implements AutoClos
private final ModuleLayer.Controller moduleController;
private final Set<String> packageNames;

private static final Map<String, Set<String>> platformModulesToServices;

static {
Set<String> unqualifiedExports = ModuleLayer.boot()
.modules()
private static Map<String, Set<String>> getModuleToServiceMap(ModuleLayer moduleLayer) {
Set<String> unqualifiedExports = moduleLayer.modules()
.stream()
.flatMap(module -> module.getDescriptor().exports().stream())
.filter(Predicate.not(ModuleDescriptor.Exports::isQualified))
.map(ModuleDescriptor.Exports::source)
.collect(Collectors.toSet());
platformModulesToServices = ModuleLayer.boot()
.modules()
return moduleLayer.modules()
.stream()
.map(Module::getDescriptor)
.filter(ModuleSupport::isJavaPlatformModule)
.filter(ModuleSupport::hasAtLeastOneUnqualifiedExport)
.collect(
Collectors.toMap(
Expand All @@ -86,27 +81,38 @@ public class UberModuleClassLoader extends SecureClassLoader implements AutoClos
}

static UberModuleClassLoader getInstance(ClassLoader parent, String moduleName, Set<URL> jarUrls) {
return getInstance(parent, moduleName, jarUrls, Set.of());
return getInstance(parent, ModuleLayer.boot(), moduleName, jarUrls, Set.of());
}

@SuppressWarnings("removal")
static UberModuleClassLoader getInstance(ClassLoader parent, String moduleName, Set<URL> jarUrls, Set<String> moduleDenyList) {
static UberModuleClassLoader getInstance(
ClassLoader parent,
ModuleLayer parentLayer,
String moduleName,
Set<URL> jarUrls,
Set<String> moduleDenyList
) {
Path[] jarPaths = jarUrls.stream().map(UberModuleClassLoader::urlToPathUnchecked).toArray(Path[]::new);

Set<String> requires = platformModulesToServices.keySet()
var parentLayerModuleToServiceMap = getModuleToServiceMap(parentLayer);
Set<String> requires = parentLayerModuleToServiceMap.keySet()
.stream()
.filter(Predicate.not(moduleDenyList::contains))
.collect(Collectors.toSet());
Set<String> uses = platformModulesToServices.entrySet()
Set<String> uses = parentLayerModuleToServiceMap.entrySet()
.stream()
.filter(Predicate.not(entry -> moduleDenyList.contains(entry.getKey())))
.flatMap(entry -> entry.getValue().stream())
.collect(Collectors.toSet());

ModuleFinder finder = ModuleSupport.ofSyntheticPluginModule(moduleName, jarPaths, requires, uses);
ModuleLayer mparent = ModuleLayer.boot();
ModuleFinder finder = ModuleSupport.ofSyntheticPluginModule(
moduleName,
jarPaths,
requires,
uses,
s -> isPackageInLayers(s, parentLayer)
);
// TODO: check that denied modules are not brought as transitive dependencies (or switch to allow-list?)
Configuration cf = mparent.configuration().resolve(finder, ModuleFinder.of(), Set.of(moduleName));
Configuration cf = parentLayer.configuration().resolve(finder, ModuleFinder.of(), Set.of(moduleName));

Set<String> packageNames = finder.find(moduleName).map(ModuleReference::descriptor).map(ModuleDescriptor::packages).orElseThrow();

Expand All @@ -115,12 +121,22 @@ static UberModuleClassLoader getInstance(ClassLoader parent, String moduleName,
moduleName,
jarUrls.toArray(new URL[0]),
cf,
mparent,
parentLayer,
packageNames
);
return AccessController.doPrivileged(pa);
}

private static boolean isPackageInLayers(String packageName, ModuleLayer moduleLayer) {
if (moduleLayer.modules().stream().map(Module::getPackages).anyMatch(p -> p.contains(packageName))) {
return true;
}
if (moduleLayer.parents().equals(List.of(ModuleLayer.empty()))) {
return false;
}
return moduleLayer.parents().stream().anyMatch(ml -> isPackageInLayers(packageName, ml));
}

/**
* Constructor
*/
Expand Down

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