Redis hash 用一个键装多个字段

redis_lab=$(mktemp -d)
curl --fail --location --output "$redis_lab/redis.tar.gz" https://download.redis.io/releases/redis-8.10.1.tar.gz
tar -xzf "$redis_lab/redis.tar.gz" -C "$redis_lab"
make -C "$redis_lab/redis-8.10.1" build redis -j2 MALLOC=libc
export REDIS_SERVER="$redis_lab/redis-8.10.1/src/redis-server"
python3 -m venv "$redis_lab/venv"
"$redis_lab/venv/bin/python" -m pip install redis==8.1.0

from contextlib import contextmanager
import os
from pathlib import Path
import subprocess
from tempfile import TemporaryDirectory
import time

import redis
from redis.backoff import NoBackoff
from redis.retry import Retry


@contextmanager
def instance():
    with TemporaryDirectory(prefix="redis-hash-", dir="/tmp") as directory:
        endpoint = str(Path(directory) / "redis.sock")
        process = subprocess.Popen([
            os.environ["REDIS_SERVER"], "--port", "0",
            "--unixsocket", endpoint, "--unixsocketperm", "700",
            "--save", "", "--appendonly", "no", "--dir", directory,
            "--hash-max-listpack-entries", "4", "--hash-max-listpack-value", "8",
        ], stdout=subprocess.DEVNULL, stderr=subprocess.PIPE)
        client = redis.Redis(unix_socket_path=endpoint, decode_responses=False,
                             socket_timeout=2, retry=Retry(NoBackoff(), 0))
        try:
            deadline = time.monotonic() + 5
            while True:
                assert process.poll() is None, "Redis exited during startup"
                try:
                    if client.ping():
                        break
                except redis.ConnectionError:
                    if time.monotonic() >= deadline:
                        raise
                    time.sleep(0.02)
            yield client
        finally:
            client.close()
            if process.poll() is None:
                process.terminate()
            try:
                _, errors = process.communicate(timeout=5)
            except subprocess.TimeoutExpired:
                process.kill()
                process.communicate()
                raise
            assert process.returncode == 0, errors.decode()


with instance() as client:
    assert client.hset("profile", mapping={"name": "Ada", "visits": "0", "empty": b""}) == 3
    assert client.hset("profile", "name", "Ada L") == 0
    assert client.hmget("profile", ["visits", "name", "missing", "empty"]) == [
        b"0", b"Ada L", None, b"",
    ]
    assert client.hmget("absent", ["a", "b"]) == [None, None]
    assert client.hgetall("profile") == {b"name": b"Ada L", b"visits": b"0", b"empty": b""}
    assert client.hincrby("profile", "visits", 1) == 1
    assert client.hget("profile", "name") == b"Ada L"
    print("HSET counts new fields; HMGET preserves order and distinguishes missing from empty")

    client.set("json", '{"name":"Ada"}')
    try:
        client.hget("json", "name")
    except redis.ResponseError as error:
        assert "WRONGTYPE" in str(error)
    else:
        raise AssertionError("a JSON string is not a hash")
    client.hset("literal", "name.first", b"Ada")
    assert client.hget("literal", "name") is None
    assert client.hget("literal", "name.first") == b"Ada"
    client.hset("invalid", "counter", "3.5")
    try:
        client.hincrby("invalid", "counter", 1)
    except redis.ResponseError as error:
        assert "integer" in str(error)
    else:
        raise AssertionError("an integer counter cannot contain 3.5")
    assert client.hget("invalid", "counter") == b"3.5"
    client.hset("overflow", "counter", 2**63 - 1)
    try:
        client.hincrby("overflow", "counter", 1)
    except redis.ResponseError as error:
        assert "overflow" in str(error)
    else:
        raise AssertionError("signed 64-bit integer overflow must fail")
    assert client.hget("overflow", "counter") == str(2**63 - 1).encode()
    print("wrong types and invalid or overflowing counters fail; dotted fields are literal")

    assert client.object("ENCODING", "profile") == b"listpack"
    assert client.hset("profile", "fourth", "ok") == 1
    assert client.object("ENCODING", "profile") == b"listpack"
    assert client.hset("profile", "fifth", "ok") == 1
    assert client.object("ENCODING", "profile") == b"hashtable"
    client.hset("value-limit", "field", b"abcdefgh")
    assert client.object("ENCODING", "value-limit") == b"listpack"
    client.hset("value-limit", "field", b"abcdefghi")
    assert client.object("ENCODING", "value-limit") == b"hashtable"
    assert client.hget("profile", "visits") == b"1"
    assert client.hget("value-limit", "field") == b"abcdefghi"
    print("private 4-field and 8-byte thresholds each trigger listpack to hashtable conversion")

    assert client.hdel("value-limit", "absent") == 0
    assert client.hdel("value-limit", "field") == 1
    assert client.exists("value-limit") == 0
    print("deleting the last field removes the hash key")