--- /dev/null
+/*
+ * Copyright (c) 2017 Cisco and/or its affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.fd.honeycomb.infra.distro.activation;
+
+import com.google.inject.Inject;
+import com.google.inject.Module;
+import com.google.inject.Provider;
+import io.fd.honeycomb.infra.distro.schema.ResourceLoader;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
+import javax.annotation.Nonnull;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Provides list of active modules for distribution
+ */
+public class ActiveModuleProvider implements Provider<ActiveModules>, ResourceLoader {
+
+ private static final Logger LOG = LoggerFactory.getLogger(ActiveModuleProvider.class);
+
+ @Inject
+ private ActivationConfig config;
+
+ @Override
+ public ActiveModules get() {
+ return new ActiveModules(loadActiveModules(
+ aggregateResources(config.getModulesResourcePath())));
+ }
+
+ /**
+ * Provide unique set of active modules filtered from provided resources
+ */
+ static Set<Class<? extends Module>> loadActiveModules(@Nonnull final List<String> moduleNames) {
+ final ClassLoader classLoader = ActiveModuleProvider.class.getClassLoader();
+ LOG.info("Reading active modules configuration for distribution");
+
+ // process resources to resource modules
+ return moduleNames.stream()
+ .map(String::trim)
+ .filter(trimmedLine -> trimmedLine.length() != 0)
+ // filter out commented lines
+ .filter(nonEmptyLine -> !nonEmptyLine.startsWith("//"))
+ // filter duplicates
+ .distinct()
+ .map(validLine -> moduleNameToClass(validLine, classLoader))
+ // filters out classes that are not modules
+ .filter(ActiveModuleProvider::filterNonModules)
+ .collect(Collectors.toSet());
+ }
+
+ /**
+ * Aggregate all resources from provided relative path into a {@code List<String>}
+ */
+ public List<String> aggregateResources(final String relativePath) {
+ // must use universal approach of loading from folder/jar
+ // because of memory footprint benchmark
+ return new ArrayList<>(loadResourceContentsOnPath(relativePath));
+ }
+
+ private static boolean filterNonModules(final Class<?> clazz) {
+ final boolean isModule = Module.class.isAssignableFrom(clazz);
+ if (!isModule) {
+ LOG.warn("Class {} is provided in modules configuration, but is not a Module and will be ignored", clazz);
+ }
+ return isModule;
+ }
+
+ /**
+ * Loads class by provided name
+ */
+ private static Class<? extends Module> moduleNameToClass(final String name,
+ final ClassLoader classLoader) {
+ try {
+ LOG.debug("Loading module class {}", name);
+ return (Class<? extends Module>) classLoader.loadClass(name);
+ } catch (ClassNotFoundException e) {
+ LOG.error("Unable to convert {} to class, make sure you've provided sources to classpath", name);
+ throw new IllegalStateException(
+ "Unable to convert " + name + " to class, make sure you've provided sources to classpath", e);
+ }
+ }
+}