《Java 网络编程基础》15.3 linkd v1 验收与故障复盘

package com.plume.linkd.app;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetSocketAddress;
import java.net.Socket;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.nio.charset.StandardCharsets;
import java.time.Duration;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

public final class AcceptanceChecklist {

    public enum Status { PASS, FAIL, SKIP }

    public record Item(String id, String chapter, String name, Status status, String detail) { }

    public static void main(String[] args) throws Exception {
        List<Item> items = run(args.length > 0 ? args[0] : "http://127.0.0.1:9090");
        System.out.printf("%-4s %-8s %-30s %-6s %s%n",
                "ID", "CHAPTER", "CHECK", "STATUS", "DETAIL");
        for (Item item : items) {
            System.out.printf("%-4s %-8s %-30s %-6s %s%n",
                    item.id(), item.chapter(), item.name(), item.status(), item.detail());
        }
        long failed = items.stream().filter(i -> i.status() == Status.FAIL).count();
        System.out.printf("total=%d pass=%d fail=%d skip=%d%n", items.size(),
                items.stream().filter(i -> i.status() == Status.PASS).count(), failed,
                items.stream().filter(i -> i.status() == Status.SKIP).count());
        if (failed > 0) System.exit(1);
    }

    public static List<Item> run(String base) throws Exception {
        List<Item> items = new ArrayList<>();
        URI uri = URI.create(base);
        int port = uri.getPort() > 0 ? uri.getPort() : 80;
        HttpClient client = HttpClient.newBuilder()
                .connectTimeout(Duration.ofSeconds(2)).build();
        items.add(expect(client, base + "/healthz", 200, "ok", "8.1", "H1"));
        items.add(expect(client, base + "/no-such-path", 404, null, "8.3", "H2"));
        items.add(keepAlive(uri.getHost(), port));
        items.add(new Item("M1", "14.3", "SIGINT graceful drain", Status.SKIP,
                "needs process control; see manual checklist"));
        items.add(new Item("M2", "10.1", "TLS handshake and ALPN", Status.SKIP,
                "needs keystore; manual keytool flow"));
        return items;
    }

    private static Item expect(HttpClient client, String url, int status,
                               String body, String chapter, String id) throws Exception {
        HttpRequest request = HttpRequest.newBuilder(URI.create(url))
                .timeout(Duration.ofSeconds(3)).GET().build();
        HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
        boolean ok = response.statusCode() == status
                && (body == null || body.equals(response.body()));
        return new Item(id, chapter, "GET " + URI.create(url).getPath(),
                ok ? Status.PASS : Status.FAIL,
                "status=" + response.statusCode() + " body=" + response.body());
    }

    private static Item keepAlive(String host, int port) {
        try (Socket socket = new Socket()) {
            socket.connect(new InetSocketAddress(host, port), 2000);
            socket.setSoTimeout(3000);
            OutputStream out = socket.getOutputStream();
            InputStream in = socket.getInputStream();
            int first = exchange(out, in, host, port);
            int second = exchange(out, in, host, port);
            boolean ok = first == 200 && second == 200;
            return new Item("H3", "8.2", "two requests, one connection",
                    ok ? Status.PASS : Status.FAIL, "first=" + first + " second=" + second);
        } catch (IOException e) {
            return new Item("H3", "8.2", "two requests, one connection",
                    Status.FAIL, e.toString());
        }
    }

    private static int exchange(OutputStream out, InputStream in, String host, int port)
            throws IOException {
        String request = "GET /healthz HTTP/1.1\r\nHost: " + host + ":" + port
                + "\r\nConnection: keep-alive\r\n\r\n";
        out.write(request.getBytes(StandardCharsets.US_ASCII));
        out.flush();
        ByteArrayOutputStream head = new ByteArrayOutputStream();
        int last4 = 0;
        while (true) {
            int b = in.read();
            if (b == -1) throw new IOException("EOF before headers");
            head.write(b);
            last4 = (last4 << 8) | b;
            if (last4 == 0x0D0A0D0A) break;
        }
        String[] lines = head.toString(StandardCharsets.ISO_8859_1).split("\r\n");
        int status = Integer.parseInt(lines[0].split(" ")[1]);
        Map<String, String> headers = new LinkedHashMap<>();
        for (int i = 1; i < lines.length; i++) {
            int colon = lines[i].indexOf(':');
            if (colon > 0) {
                headers.put(lines[i].substring(0, colon).toLowerCase(),
                        lines[i].substring(colon + 1).trim());
            }
        }
        in.readNBytes(Integer.parseInt(headers.getOrDefault("content-length", "0")));
        return status;
    }
}

java -cp out com.plume.linkd.app.AcceptanceChecklist http://127.0.0.1:9091

ID   CHAPTER  CHECK                          STATUS DETAIL
H1   8.1      GET /healthz                   PASS   status=200 body=ok
H2   8.3      GET /no-such-path              PASS   status=404 body=not found
H3   8.2      two requests, one connection   PASS   first=200 second=200
M1   14.3     SIGINT graceful drain          SKIP   needs process control; see manual checklist
M2   10.1     TLS handshake and ALPN         SKIP   needs keystore; manual keytool flow
total=5 pass=3 fail=0 skip=2

# <一句话标题>
## 影响
受影响接口、时间段、错误率、用户可见现象。
## 时间线
UTC+8 时间 | 事件 | 证据来源
## 根因
直接原因、触发条件、为什么现有测试没发现。
## 处置
止血动作、恢复时间、是否回滚。
## 改进项
动作 | 负责人 | 截止日期 | 对应章节

# linkd /books 延迟升高与 fd 耗尽

## 影响
21:40–22:05，/books/{id} p99 从 30ms 升到 8s，错误率 12%；
fd 从 800 涨到 6100，22:03 起新连接被拒。

## 时间线
21:40 | 监控告警 p99 > 1s | 指标面板
21:44 | netstat 显示 4200 条 CLOSE_WAIT | 现场快照
21:52 | jcmd 显示 8 个线程停在 read0 | 线程转储
22:01 | 确认 libraryd 在 21:38 重启过 | 发布记录
22:05 | 回滚 linkd 到上一版，fd 回落 | 部署系统

## 根因
onReadable 收到 -1 后只 return，没有调用 Connection.close()；
对端重启时大量连接同时半关闭，socket 停在 CLOSE_WAIT。
现有验收只测 /healthz，没有注入对端重启。

## 处置
22:05 回滚；22:20 补丁在 EOF 分支调用 close()；22:40 灰度 10%。

## 改进项
EOF 分支补 close() | 张 | 10-30 | 7.3、14.3
CLOSE_WAIT > 100 持续 1 分钟告警 | 李 | 10-31 | 15.1
验收加入对端重启注入 | 王 | 11-02 | 15.3