org.springframework.boot.env.RandomValuePropertySource Maven / Gradle / Ivy
/*
* Copyright 2012-2021 the original author or authors.
*
* 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
*
* https://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.springframework.boot.env;
import java.util.OptionalInt;
import java.util.OptionalLong;
import java.util.Random;
import java.util.UUID;
import java.util.function.Function;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.core.env.ConfigurableEnvironment;
import org.springframework.core.env.MutablePropertySources;
import org.springframework.core.env.PropertySource;
import org.springframework.core.env.StandardEnvironment;
import org.springframework.core.log.LogMessage;
import org.springframework.util.Assert;
import org.springframework.util.DigestUtils;
import org.springframework.util.StringUtils;
/**
* {@link PropertySource} that returns a random value for any property that starts with
* {@literal "random."}. Where the "unqualified property name" is the portion of the
* requested property name beyond the "random." prefix, this {@link PropertySource}
* returns:
*
* - When {@literal "int"}, a random {@link Integer} value, restricted by an optionally
* specified range.
* - When {@literal "long"}, a random {@link Long} value, restricted by an optionally
* specified range.
* - Otherwise, a {@code byte[]}.
*
* The {@literal "random.int"} and {@literal "random.long"} properties supports a range
* suffix whose syntax is:
*
* {@code OPEN value (,max) CLOSE} where the {@code OPEN,CLOSE} are any character and
* {@code value,max} are integers. If {@code max} is not provided, then 0 is used as the
* lower bound and {@code value} is the upper bound. If {@code max} is provided then
* {@code value} is the minimum value and {@code max} is the maximum (exclusive).
*
* @author Dave Syer
* @author Matt Benson
* @author Madhura Bhave
* @since 1.0.0
*/
public class RandomValuePropertySource extends PropertySource {
/**
* Name of the random {@link PropertySource}.
*/
public static final String RANDOM_PROPERTY_SOURCE_NAME = "random";
private static final String PREFIX = "random.";
private static final Log logger = LogFactory.getLog(RandomValuePropertySource.class);
public RandomValuePropertySource() {
this(RANDOM_PROPERTY_SOURCE_NAME);
}
public RandomValuePropertySource(String name) {
super(name, new Random());
}
@Override
public Object getProperty(String name) {
if (!name.startsWith(PREFIX)) {
return null;
}
logger.trace(LogMessage.format("Generating random property for '%s'", name));
return getRandomValue(name.substring(PREFIX.length()));
}
private Object getRandomValue(String type) {
if (type.equals("int")) {
return getSource().nextInt();
}
if (type.equals("long")) {
return getSource().nextLong();
}
String range = getRange(type, "int");
if (range != null) {
return getNextIntInRange(Range.of(range, Integer::parseInt));
}
range = getRange(type, "long");
if (range != null) {
return getNextLongInRange(Range.of(range, Long::parseLong));
}
if (type.equals("uuid")) {
return UUID.randomUUID().toString();
}
return getRandomBytes();
}
private String getRange(String type, String prefix) {
if (type.startsWith(prefix)) {
int startIndex = prefix.length() + 1;
if (type.length() > startIndex) {
return type.substring(startIndex, type.length() - 1);
}
}
return null;
}
private int getNextIntInRange(Range range) {
OptionalInt first = getSource().ints(1, range.getMin(), range.getMax()).findFirst();
assertPresent(first.isPresent(), range);
return first.getAsInt();
}
private long getNextLongInRange(Range range) {
OptionalLong first = getSource().longs(1, range.getMin(), range.getMax()).findFirst();
assertPresent(first.isPresent(), range);
return first.getAsLong();
}
private void assertPresent(boolean present, Range range) {
Assert.state(present, () -> "Could not get random number for range '" + range + "'");
}
private Object getRandomBytes() {
byte[] bytes = new byte[32];
getSource().nextBytes(bytes);
return DigestUtils.md5DigestAsHex(bytes);
}
public static void addToEnvironment(ConfigurableEnvironment environment) {
addToEnvironment(environment, logger);
}
static void addToEnvironment(ConfigurableEnvironment environment, Log logger) {
MutablePropertySources sources = environment.getPropertySources();
PropertySource existing = sources.get(RANDOM_PROPERTY_SOURCE_NAME);
if (existing != null) {
logger.trace("RandomValuePropertySource already present");
return;
}
RandomValuePropertySource randomSource = new RandomValuePropertySource(RANDOM_PROPERTY_SOURCE_NAME);
if (sources.get(StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME) != null) {
sources.addAfter(StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME, randomSource);
}
else {
sources.addLast(randomSource);
}
logger.trace("RandomValuePropertySource add to Environment");
}
static final class Range {
private final String value;
private final T min;
private final T max;
private Range(String value, T min, T max) {
this.value = value;
this.min = min;
this.max = max;
}
T getMin() {
return this.min;
}
T getMax() {
return this.max;
}
@Override
public String toString() {
return this.value;
}
static > Range of(String value, Function parse) {
T zero = parse.apply("0");
String[] tokens = StringUtils.commaDelimitedListToStringArray(value);
T min = parse.apply(tokens[0]);
if (tokens.length == 1) {
Assert.isTrue(min.compareTo(zero) > 0, "Bound must be positive.");
return new Range<>(value, zero, min);
}
T max = parse.apply(tokens[1]);
Assert.isTrue(min.compareTo(max) < 0, "Lower bound must be less than upper bound.");
return new Range<>(value, min, max);
}
}
}