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Improved resilience of registry communication.

This commit is contained in:
Andrew Lalis 2021-06-30 13:06:11 +02:00
parent b0a289e35f
commit b72a5a8b7a
8 changed files with 146 additions and 23 deletions
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43
server-registry/src/main/java/nl/andrewlalis/aos_server_registry/servlet/ServerInfoServlet.java
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@ -7,7 +7,6 @@ import nl.andrewlalis.aos_server_registry.servlet.dto.ServerStatusUpdate;
import nl.andrewlalis.aos_server_registry.util.Requests;
import nl.andrewlalis.aos_server_registry.util.Responses;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@ -22,7 +21,7 @@ import java.util.Map;
public class ServerInfoServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException {
int page = Requests.getIntParam(req, "page", 0, i -> i >= 0);
int size = Requests.getIntParam(req, "size", 20, i -> i >= 5 && i <= 50);
String searchQuery = Requests.getStringParam(req, "q", null, s -> !s.isBlank());
@ -44,7 +43,7 @@ public class ServerInfoServlet extends HttpServlet {
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
var info = Requests.getBody(req, ServerInfoUpdate.class);
try {
this.saveNewServer(info);
@ -56,15 +55,9 @@ public class ServerInfoServlet extends HttpServlet {
}
@Override
protected void doPut(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
protected void doPut(HttpServletRequest req, HttpServletResponse resp) throws IOException {
var status = Requests.getBody(req, ServerStatusUpdate.class);
try {
this.updateServerStatus(status);
Responses.ok(resp, Map.of("message", "Server status updated."));
} catch (SQLException e) {
e.printStackTrace();
Responses.internalServerError(resp, "Database error.");
}
this.updateServerStatus(status, resp);
}
private List<ServerInfoResponse> getData(int size, int page, String searchQuery, String order, String orderDir) throws SQLException {
@ -146,18 +139,26 @@ public class ServerInfoServlet extends HttpServlet {
}
}
private void updateServerStatus(ServerStatusUpdate status) throws SQLException {
var con = DataManager.getInstance().getConnection();
PreparedStatement stmt = con.prepareStatement("""
private void updateServerStatus(ServerStatusUpdate status, HttpServletResponse resp) throws IOException {
try {
var con = DataManager.getInstance().getConnection();
PreparedStatement stmt = con.prepareStatement("""
UPDATE servers SET current_players = ?
WHERE name = ? AND address = ?
""");
stmt.setInt(1, status.currentPlayers());
stmt.setString(2, status.name());
stmt.setString(3, status.address());
int rowCount = stmt.executeUpdate();
stmt.close();
if (rowCount != 1) throw new SQLException("Could not update server status.");
System.out.println("Updated server status for " + status.name() + " @ " + status.address());
stmt.setInt(1, status.currentPlayers());
stmt.setString(2, status.name());
stmt.setString(3, status.address());
int rowCount = stmt.executeUpdate();
stmt.close();
if (rowCount != 1) {
Responses.notFound(resp);
} else {
Responses.ok(resp);
}
} catch (SQLException e) {
e.printStackTrace();
Responses.internalServerError(resp, "Database error.");
}
}
}

4
server-registry/src/main/java/nl/andrewlalis/aos_server_registry/util/Responses.java
View File

@ -11,6 +11,10 @@ import static nl.andrewlalis.aos_server_registry.ServerRegistry.mapper;
* JSON responses.
*/
public class Responses {
public static void ok(HttpServletResponse resp) {
resp.setStatus(HttpServletResponse.SC_OK);
}
public static void ok(HttpServletResponse resp, Object body) throws IOException {
resp.setStatus(HttpServletResponse.SC_OK);
resp.setContentType("application/json");

1
server/src/main/java/module-info.java
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@ -2,6 +2,7 @@ module aos_server {
requires java.logging;
requires aos_core;
requires java.desktop;
requires java.net.http;
requires com.fasterxml.jackson.databind;
requires com.fasterxml.jackson.dataformat.yaml;

97
server/src/main/java/nl/andrewlalis/aos_server/RegistryManager.java Normal file
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@ -0,0 +1,97 @@
package nl.andrewlalis.aos_server;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.time.Duration;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
/**
* The registry manager is responsible for keeping the server registry up to
* date with this server's information, by sending periodic update HTTP messages.
*/
public class RegistryManager {
private final ScheduledExecutorService executorService;
private final Server server;
private final ObjectMapper mapper;
private final HttpClient httpClient;
public RegistryManager(Server server) {
this.server = server;
this.mapper = new ObjectMapper();
this.executorService = Executors.newScheduledThreadPool(3);
this.httpClient = HttpClient.newBuilder()
.executor(this.executorService)
.connectTimeout(Duration.ofSeconds(3))
.build();
this.executorService.submit(this::sendInfo);
this.executorService.scheduleAtFixedRate(
this::sendUpdate,
server.getSettings().getRegistrySettings().getUpdateInterval(),
server.getSettings().getRegistrySettings().getUpdateInterval(),
TimeUnit.SECONDS
);
}
public void sendInfo() {
try {
Map<String, Object> data = new HashMap<>();
data.put("name", this.server.getSettings().getRegistrySettings().getName());
data.put("address", this.server.getSettings().getRegistrySettings().getAddress());
data.put("description", this.server.getSettings().getRegistrySettings().getDescription());
data.put("location", this.server.getSettings().getRegistrySettings().getLocation());
data.put("maxPlayers", this.server.getSettings().getMaxPlayers());
data.put("currentPlayers", 0);
HttpRequest request = HttpRequest.newBuilder()
.uri(new URI(this.server.getSettings().getRegistrySettings().getRegistryUri() + "/serverInfo"))
.POST(HttpRequest.BodyPublishers.ofByteArray(this.mapper.writeValueAsBytes(data)))
.header("Content-Type", "application/json")
.build();
this.httpClient.sendAsync(request, HttpResponse.BodyHandlers.discarding());
} catch (Exception e) {
e.printStackTrace();
}
}
private void sendUpdate() {
try {
Map<String, Object> data = new HashMap<>();
data.put("name", this.server.getSettings().getRegistrySettings().getName());
data.put("address", this.server.getSettings().getRegistrySettings().getAddress());
data.put("currentPlayers", server.getPlayerCount());
HttpRequest request = HttpRequest.newBuilder()
.uri(new URI(this.server.getSettings().getRegistrySettings().getRegistryUri() + "/serverInfo"))
.PUT(HttpRequest.BodyPublishers.ofByteArray(this.mapper.writeValueAsBytes(data)))
.header("Content-Type", "application/json")
.build();
this.httpClient.sendAsync(request, responseInfo -> {
if (responseInfo.statusCode() == 404) {
System.out.println("Received 404 when sending registry update. Re-sending registry info...");
this.sendInfo();
}
return null;
});
} catch (Exception e) {
e.printStackTrace();
}
}
public void shutdown() {
this.executorService.shutdown();
try {
while (!this.executorService.awaitTermination(3, TimeUnit.SECONDS)) {
System.out.println("Waiting for scheduler to terminate.");
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}

12
server/src/main/java/nl/andrewlalis/aos_server/Server.java
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@ -25,7 +25,9 @@ import java.net.Socket;
import java.net.SocketException;
import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.TimeUnit;
public class Server {
private final ServerSettings settings;
@ -37,6 +39,7 @@ public class Server {
private final WorldUpdater worldUpdater;
private final ServerCli cli;
private final ChatManager chatManager;
private RegistryManager registryManager;
private volatile boolean running;
@ -50,6 +53,9 @@ public class Server {
this.initWorld();
this.worldUpdater = new WorldUpdater(this, this.world);
this.chatManager = new ChatManager(this);
if (settings.getRegistrySettings().isDiscoverable()) {
this.registryManager = new RegistryManager(this);
}
}
public ServerSettings getSettings() {
@ -230,7 +236,7 @@ public class Server {
handler.send(new Message(Type.SERVER_SHUTDOWN));
handler.shutdown();
}
} catch (IOException e) {
} catch (Exception e) {
System.err.println("Could not close server socket on shutdown: " + e.getMessage());
}
}
@ -252,6 +258,10 @@ public class Server {
System.out.println("Stopped CLI interface.");
this.dataTransceiver.shutdown();
System.out.println("Stopped data transceiver.");
if (this.registryManager != null) {
this.registryManager.shutdown();
System.out.println("Stopped registry communications.");
}
}

5
server/src/main/java/nl/andrewlalis/aos_server/settings/RegistrySettings.java
View File

@ -3,6 +3,7 @@ package nl.andrewlalis.aos_server.settings;
public class RegistrySettings {
private boolean discoverable;
private String registryUri;
private long updateInterval;
private String name;
private String address;
private String description;
@ -16,6 +17,10 @@ public class RegistrySettings {
return registryUri;
}
public long getUpdateInterval() {
return updateInterval;
}
public String getName() {
return name;
}

4
server/src/main/java/nl/andrewlalis/aos_server/settings/ServerSettings.java
View File

@ -24,6 +24,10 @@ public class ServerSettings {
return ticksPerSecond;
}
public RegistrySettings getRegistrySettings() {
return registrySettings;
}
public PlayerSettings getPlayerSettings() {
return playerSettings;
}

3
server/src/main/resources/default_settings.yaml
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@ -3,9 +3,10 @@ max-players: 32
ticks-per-second: 120
# Information for the public server registry.
registry-data:
registry-settings:
discoverable: true
registry-uri: "http://localhost:8567"
update-interval: 10
name: "Testing Server"
address: "localhost:8035"
description: "A simple testing server for development."