dsmiley commented on code in PR #1935: URL: https://github.com/apache/solr/pull/1935#discussion_r1435763892
########## solr/core/src/java/org/apache/solr/util/EnvUtils.java: ########## @@ -0,0 +1,279 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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 org.apache.solr.util; + +import java.io.IOException; +import java.io.InputStream; +import java.io.InputStreamReader; +import java.nio.charset.StandardCharsets; +import java.util.HashMap; +import java.util.List; +import java.util.Locale; +import java.util.Map; +import java.util.Objects; +import java.util.Properties; +import java.util.SortedMap; +import java.util.TreeMap; +import java.util.stream.Collectors; +import org.apache.solr.common.SolrException; +import org.apache.solr.common.util.StrUtils; +import org.apache.solr.common.util.Utils; + +/** + * This class is a unified provider of environment variables and system properties. It exposes a + * mutable copy of the environment variables. It also converts 'SOLR_FOO' variables to system + * properties 'solr.foo' and provide various convenience accessors for them. + */ +public class EnvUtils { + private static final SortedMap<String, String> ENV = new TreeMap<>(System.getenv()); + private static final Map<String, String> CUSTOM_MAPPINGS = new HashMap<>(); + private static boolean initialized = false; + + static { + try { + Properties props = new Properties(); + try (InputStream stream = + EnvUtils.class.getClassLoader().getResourceAsStream("EnvToSyspropMappings.properties")) { + props.load(new InputStreamReader(Objects.requireNonNull(stream), StandardCharsets.UTF_8)); + for (String key : props.stringPropertyNames()) { + CUSTOM_MAPPINGS.put(key, props.getProperty(key)); + } + init(false); + } + } catch (IOException e) { + throw new SolrException( + SolrException.ErrorCode.INVALID_STATE, "Failed loading env.var->properties mapping", e); + } + } + + /** + * Get Solr's mutable copy of all environment variables. + * + * @return sorted map of environment variables + */ + public static SortedMap<String, String> getEnvs() { + return ENV; + } + + /** Get a single environment variable as string */ + public static String getEnv(String key) { + return ENV.get(key); + } + + /** Get a single environment variable as string, or default */ + public static String getEnv(String key, String defaultValue) { + return ENV.getOrDefault(key, defaultValue); + } + + /** Get an environment variable as long */ + public static long getEnvAsLong(String key) { + return Long.parseLong(ENV.get(key)); + } + + /** Get an environment variable as long, or default value */ + public static long getEnvAsLong(String key, long defaultValue) { + String value = ENV.get(key); + if (value == null) { + return defaultValue; + } + return Long.parseLong(value); + } + + /** Get an env var as boolean */ + public static boolean getEnvAsBool(String key) { + return StrUtils.parseBool(ENV.get(key)); + } + + /** Get an env var as boolean, or default value */ + public static boolean getEnvAsBool(String key, boolean defaultValue) { + String value = ENV.get(key); + if (value == null) { + return defaultValue; + } + return StrUtils.parseBool(value); + } + + /** Get comma separated strings from env as List */ + public static List<String> getEnvAsList(String key) { + return getEnv(key) != null ? stringValueToList(getEnv(key)) : null; + } + + /** Get comma separated strings from env as List */ + public static List<String> getEnvAsList(String key, List<String> defaultValue) { + return ENV.get(key) != null ? getEnvAsList(key) : defaultValue; + } + + /** Set an environment variable */ + public static void setEnv(String key, String value) { + ENV.put(key, value); + } + + /** Set all environment variables */ + public static synchronized void setEnvs(Map<String, String> env) { + ENV.clear(); + ENV.putAll(env); + } + + /** Get all Solr system properties as a sorted map */ + public static SortedMap<String, String> getProps() { + ensureInitialized(); + SortedMap<String, String> props = new TreeMap<>(); + for (String key : System.getProperties().stringPropertyNames()) { + props.put(key, System.getProperty(key)); + } + return props; + } + + /** Get a property as string */ + public static String getProp(String key) { + return getProp(key, null); + } + + /** + * Get a property as string with a fallback value. All other getProp* methods use this. + * + * @param key property key, which treats 'camelCase' the same as 'camel.case' + */ + public static String getProp(String key, String defaultValue) { + ensureInitialized(); // Avoid race condition with init() + String value = getPropWithCamelCaseFallback(key); + return value != null ? value : defaultValue; + } + + /** + * Get a property from given key or an alias key converted from CamelCase to dot separated. + * + * @return property value or value of dot-separated alias key or null if not found + */ + private static String getPropWithCamelCaseFallback(String key) { + String value = System.getProperty(key); + if (value != null) { + return value; + } else { + // Figure out if string is CamelCase and convert to dot separated + String altKey = camelCaseToDotSeparated(key); + return System.getProperty(altKey); + } + } + + private static String camelCaseToDotSeparated(String key) { + return String.join(".", key.split("(?=[A-Z])")).replace("..", ".").toLowerCase(Locale.ROOT); + } + + /** Get property as integer */ + public static Long getPropAsLong(String key) { + return getPropAsLong(key, null); + } + + /** Get property as long, or default value */ + public static Long getPropAsLong(String key, Long defaultValue) { + String value = getProp(key); + if (value == null) { + return defaultValue; + } + return Long.parseLong(value); + } + + /** Get property as boolean */ + public static Boolean getPropAsBool(String key) { + return getPropAsBool(key, null); + } + + /** Get property as boolean, or default value */ + public static Boolean getPropAsBool(String key, Boolean defaultValue) { + String value = getProp(key); + if (value == null) { + return defaultValue; + } + return StrUtils.parseBool(value); + } + + /** + * Get comma separated strings from sysprop as List + * + * @return list of strings, or null if not found + */ + public static List<String> getPropAsList(String key) { + return getPropAsList(key, null); + } + + /** + * Get comma separated strings from sysprop as List, or default value + * + * @return list of strings, or provided default if not found + */ + public static List<String> getPropAsList(String key, List<String> defaultValue) { + return getProp(key) != null ? stringValueToList(getProp(key)) : defaultValue; + } + + /** Set a system property. Shim to {@link System#setProperty(String, String)} */ + public static void setProp(String key, String value) { + System.setProperty(key, value); + System.setProperty(camelCaseToDotSeparated(key), value); + } + + /** + * Re-reads environment variables and updates the internal map. + * + * @param overwrite if true, overwrite existing system properties with environment variables + */ + public static synchronized void init(boolean overwrite) { + // Convert eligible environment variables to system properties + for (String key : ENV.keySet().toArray(String[]::new)) { + if (key.startsWith("SOLR_") || CUSTOM_MAPPINGS.containsKey(key)) { + String sysPropKey = envNameToSyspropName(key); + // Existing system properties take precedence + if (!sysPropKey.isBlank() && (overwrite || getProp(sysPropKey) == null)) { + setProp(sysPropKey, ENV.get(key)); + } + } + } + initialized = true; + } + + protected static String envNameToSyspropName(String envName) { + return CUSTOM_MAPPINGS.containsKey(envName) + ? CUSTOM_MAPPINGS.get(envName) + : envName.toLowerCase(Locale.ROOT).replace("_", "."); + } + + @SuppressWarnings("unchecked") + private static List<String> stringValueToList(String string) { + if (string.startsWith("[") && string.endsWith("]")) { + // Convert a JSON string to a List<String> using Noggit parser + return (List<String>) Utils.fromJSONString(string); + } else { + return StrUtils.splitSmart(string, ",", true).stream() + .map(String::trim) + .collect(Collectors.toList()); + } + } + + private static synchronized void ensureInitialized() { Review Comment: The JVM will block any thread from calling `getProp` (or accessing `EnvUtils` in any way) until `EnvUtils` is initialized. Initialization of this class calls init(). See [section 12.4.2 of the Java Language Specification](https://docs.oracle.com/javase/specs/jls/se8/html/jls-12.html#jls-12.4.2), particularly references to "LC". I'm aware init() indirectly calls getProp but it proceeds because this thread holds the LC lock. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@solr.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@solr.apache.org For additional commands, e-mail: issues-h...@solr.apache.org
