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Revise TestSocketUtils and tests

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Closes gh-29132
This commit is contained in:
Sam Brannen
2022-11-14 20:00:22 +01:00
parent ee51dab1f3
commit 698f8995f7
3 changed files with 83 additions and 48 deletions
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92
spring-test/src/main/java/org/springframework/test/util/TestSocketUtils.java
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@@ -22,23 +22,24 @@ import java.util.Random;
import javax.net.ServerSocketFactory;
import org.springframework.util.Assert;
/**
* Simple utility methods for finding available ports on {@code localhost} for
* use in integration testing scenarios.
* Simple utility for finding available TCP ports on {@code localhost} for use in
* integration testing scenarios.
*
* <p>This is a limited form of {@code SocketUtils} which is deprecated in Spring
* Framework 5.3 and removed in Spring Framework 6.0.
* <p>This is a limited form of {@link org.springframework.util.SocketUtils} which
* has been deprecated since Spring Framework 5.3.16 and removed in Spring
* Framework 6.0.
*
* <p>{@code SocketUtils} was introduced in Spring Framework 4.0, primarily to
* assist in writing integration tests which start an external server on an
* available random port. However, these utilities make no guarantee about the
* subsequent availability of a given port and are therefore unreliable (the reason
* for deprecation and removal).
*
* <p>Instead of using {@code TestSocketUtils} to find an available local port for a server,
* it is recommended that you rely on a server's ability to start on a random port
* that it selects or is assigned by the operating system. To interact with that
* server, you should query the server for the port it is currently using.
* <p>{@code TestSocketUtils} can be used in integration tests which start an
* external server on an available random port. However, these utilities make no
* guarantee about the subsequent availability of a given port and are therefore
* unreliable. Instead of using {@code TestSocketUtils} to find an available local
* port for a server, it is recommended that you rely on a server's ability to
* start on a random <em>ephemeral</em> port that it selects or is assigned by the
* operating system. To interact with that server, you should query the server
* for the port it is currently using.
*
* @author Sam Brannen
* @author Ben Hale
@@ -46,45 +47,73 @@ import javax.net.ServerSocketFactory;
* @author Gunnar Hillert
* @author Gary Russell
* @author Chris Bono
* @since 5.3
* @since 5.3.24
*/
public final class TestSocketUtils {
public class TestSocketUtils {
/**
* The minimum value for port ranges used when finding an available TCP port.
*/
private static final int PORT_RANGE_MIN = 1024;
static final int PORT_RANGE_MIN = 1024;
/**
* The maximum value for port ranges used when finding an available TCP port.
*/
private static final int PORT_RANGE_MAX = 65535;
static final int PORT_RANGE_MAX = 65535;
private static final int PORT_RANGE = PORT_RANGE_MAX - PORT_RANGE_MIN;
private static final int PORT_RANGE_PLUS_ONE = PORT_RANGE_MAX - PORT_RANGE_MIN + 1;
private static final int MAX_ATTEMPTS = 1_000;
private static final Random random = new Random(System.nanoTime());
private TestSocketUtils() {
private static final TestSocketUtils INSTANCE = new TestSocketUtils();
/**
* Although {@code TestSocketUtils} consists solely of static utility methods,
* this constructor is intentionally {@code public}.
* <h4>Rationale</h4>
* <p>Static methods from this class may be invoked from within XML
* configuration files using the Spring Expression Language (SpEL) and the
* following syntax.
* <pre><code>
* &lt;bean id="myBean" ... p:port="#{T(org.springframework.test.util.TestSocketUtils).findAvailableTcpPort()}" /&gt;</code>
* </pre>
* <p>If this constructor were {@code private}, you would be required to supply
* the fully qualified class name to SpEL's {@code T()} function for each usage.
* Thus, the fact that this constructor is {@code public} allows you to reduce
* boilerplate configuration with SpEL as can be seen in the following example.
* <pre><code>
* &lt;bean id="socketUtils" class="org.springframework.test.util.TestSocketUtils" /&gt;
* &lt;bean id="myBean" ... p:port="#{socketUtils.findAvailableTcpPort()}" /&gt;</code>
* </pre>
*/
public TestSocketUtils() {
}
/**
* Find an available TCP port randomly selected from the range [1024, 65535].
* @return an available TCP port number
* @throws IllegalStateException if no available port could be found within max attempts
* @throws IllegalStateException if no available port could be found
*/
public static int findAvailableTcpPort() {
return INSTANCE.findAvailableTcpPortInternal();
}
/**
* Internal implementation of {@link #findAvailableTcpPort()}.
* <p>Package-private solely for testing purposes.
*/
int findAvailableTcpPortInternal() {
int candidatePort;
int searchCounter = 0;
do {
if (searchCounter > MAX_ATTEMPTS) {
throw new IllegalStateException(String.format(
"Could not find an available TCP port in the range [%d, %d] after %d attempts",
PORT_RANGE_MIN, PORT_RANGE_MAX, MAX_ATTEMPTS));
}
candidatePort = PORT_RANGE_MIN + random.nextInt(PORT_RANGE + 1);
searchCounter++;
Assert.state(++searchCounter <= MAX_ATTEMPTS, () -> String.format(
"Could not find an available TCP port in the range [%d, %d] after %d attempts",
PORT_RANGE_MIN, PORT_RANGE_MAX, MAX_ATTEMPTS));
candidatePort = PORT_RANGE_MIN + random.nextInt(PORT_RANGE_PLUS_ONE);
}
while (!isPortAvailable(candidatePort));
@@ -93,11 +122,12 @@ public final class TestSocketUtils {
/**
* Determine if the specified TCP port is currently available on {@code localhost}.
* <p>Package-private solely for testing purposes.
*/
private static boolean isPortAvailable(int port) {
boolean isPortAvailable(int port) {
try {
ServerSocket serverSocket = ServerSocketFactory.getDefault().createServerSocket(
port, 1, InetAddress.getByName("localhost"));
ServerSocket serverSocket = ServerSocketFactory.getDefault()
.createServerSocket(port, 1, InetAddress.getByName("localhost"));
serverSocket.close();
return true;
}