基本上，我正在编写一些程序来测试给定表增长情况下PostgreSQL的插入性能，并且我想确保在使用Marten插入数据时，数据库是完全准备好接受插入。
我正在使用Docker.DotNet生成一个运行最新PostgreSQL映像的新容器，但是即使该容器处于running状态，在该容器中运行Postgre有时也并非如此
当然，我可以添加一个Thread. Sleep，但这有点随机，所以我希望确定性地找出数据库何时准备接受插入？
public static class Program
{
public static async Task Main(params string[] args)
{
const string imageName = "postgres:latest";
const string containerName = "MyProgreSQL";
var client = new DockerClientConfiguration(Docker.DefaultLocalApiUri).CreateClient();
var containers = await client.Containers.SearchByNameAsync(containerName);
var container = containers.SingleOrDefault();
if (container != null)
{
await client.Containers.StopAndRemoveContainerAsync(container);
}
var createdContainer = await client.Containers.RunContainerAsync(new CreateContainerParameters
{
Image = imageName,
HostConfig = new HostConfig
{
PortBindings = new Dictionary<string, IList<PortBinding>>
{
{"5432/tcp", new List<PortBinding>
{
new PortBinding
{
HostPort = "5432"
}
}}
},
PublishAllPorts = true
},
Env = new List<string>
{
"POSTGRES_PASSWORD=root",
"POSTGRES_USER=root"
},
Name = containerName
});
var containerState = string.Empty;
while (containerState != "running")
{
containers = await client.Containers.SearchByNameAsync(containerName);
container = containers.Single();
containerState = container.State;
}
var store = DocumentStore.For("host=localhost;database=postgres;password=root;username=root");
var stopwatch = new Stopwatch();
using (var session = store.LightweightSession())
{
var orders = OrderHelpers.FakeOrders(10000);
session.StoreObjects(orders);
stopwatch.Start();
await session.SaveChangesAsync();
var elapsed = stopwatch.Elapsed;
// Whatever else needs to be done...
}
}
}
仅供参考，如果我正在运行上面的程序而没有暂停await session.SaveChangesAsync();行之前，则发生以下异常：
Unhandled Exception: Npgsql.NpgsqlException: Exception while reading from stream ---> System.IO.EndOfStreamException: Attempted to read past the end of the streams.
at Npgsql.NpgsqlReadBuffer.<>c__DisplayClass31_0.<<Ensure>g__EnsureLong|0>d.MoveNext() in C:\projects\npgsql\src\Npgsql\NpgsqlReadBuffer.cs:line 154
--- End of inner exception stack trace ---
at Npgsql.NpgsqlReadBuffer.<>c__DisplayClass31_0.<<Ensure>g__EnsureLong|0>d.MoveNext() in C:\projects\npgsql\src\Npgsql\NpgsqlReadBuffer.cs:line 175
--- End of stack trace from previous location where exception was thrown ---
at Npgsql.NpgsqlConnector.<>c__DisplayClass161_0.<<ReadMessage>g__ReadMessageLong|0>d.MoveNext() in C:\projects\npgsql\src\Npgsql\NpgsqlConnector.cs:l
ine 955
--- End of stack trace from previous location where exception was thrown ---
at Npgsql.NpgsqlConnector.Authenticate(String username, NpgsqlTimeout timeout, Boolean async) in C:\projects\npgsql\src\Npgsql\NpgsqlConnector.Auth.cs
:line 26
at Npgsql.NpgsqlConnector.Open(NpgsqlTimeout timeout, Boolean async, CancellationToken cancellationToken) in C:\projects\npgsql\src\Npgsql\NpgsqlConne
ctor.cs:line 425
at Npgsql.ConnectorPool.AllocateLong(NpgsqlConnection conn, NpgsqlTimeout timeout, Boolean async, CancellationToken cancellationToken) in C:\projects\
npgsql\src\Npgsql\ConnectorPool.cs:line 246
at Npgsql.NpgsqlConnection.<>c__DisplayClass32_0.<<Open>g__OpenLong|0>d.MoveNext() in C:\projects\npgsql\src\Npgsql\NpgsqlConnection.cs:line 300
--- End of stack trace from previous location where exception was thrown ---
at Npgsql.NpgsqlConnection.Open() in C:\projects\npgsql\src\Npgsql\NpgsqlConnection.cs:line 153
at Marten.Storage.Tenant.generateOrUpdateFeature(Type featureType, IFeatureSchema feature)
at Marten.Storage.Tenant.ensureStorageExists(IList`1 types, Type featureType)
at Marten.Storage.Tenant.ensureStorageExists(IList`1 types, Type featureType)
at Marten.Storage.Tenant.StorageFor(Type documentType)
at Marten.DocumentSession.Store[T](T[] entities)
at Baseline.GenericEnumerableExtensions.Each[T](IEnumerable`1 values, Action`1 eachAction)
at Marten.DocumentSession.StoreObjects(IEnumerable`1 documents)
at Benchmark.Program.Main(String[] args) in C:\Users\eperret\Desktop\Benchmark\Benchmark\Program.cs:line 117
at Benchmark.Program.<Main>(String[] args)
[编辑]
我接受了一个答案，但是由于Docker.DotNet中有关健康参数等效的错误，我无法利用答案中给出的解决方案（我仍然认为在.NET客户端中该docker命令的正确翻译，如果实际可能）将是最好的解决方案。同时，这就是我解决问题的方式，基本上，我会轮询预期在运行状况检查中运行的命令，直到结果正常：
Program.cs，代码的实际内容：
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Threading.Tasks;
using Benchmark.DockerClient;
using Benchmark.Domain;
using Benchmark.Utils;
using Docker.DotNet;
using Docker.DotNet.Models;
using Marten;
using Microsoft.Extensions.Configuration;
namespace Benchmark
{
public static class Program
{
public static async Task Main(params string[] args)
{
var configurationBuilder = new ConfigurationBuilder()
.SetBasePath(Directory.GetCurrentDirectory())
.AddJsonFile("appsettings.json");
var configuration = new Configuration();
configurationBuilder.Build().Bind(configuration);
var client = new DockerClientConfiguration(DockerClient.Docker.DefaultLocalApiUri).CreateClient();
var containers = await client.Containers.SearchByNameAsync(configuration.ContainerName);
var container = containers.SingleOrDefault();
if (container != null)
{
await client.Containers.StopAndRemoveContainerAsync(container.ID);
}
var createdContainer = await client.Containers.RunContainerAsync(new CreateContainerParameters
{
Image = configuration.ImageName,
HostConfig = new HostConfig
{
PortBindings = new Dictionary<string, IList<PortBinding>>
{
{$@"{configuration.ContainerPort}/{configuration.ContainerPortProtocol}", new List<PortBinding>
{
new PortBinding
{
HostPort = configuration.HostPort
}
}}
},
PublishAllPorts = true
},
Env = new List<string>
{
$"POSTGRES_USER={configuration.Username}",
$"POSTGRES_PASSWORD={configuration.Password}"
},
Name = configuration.ContainerName
});
var isContainerReady = false;
while (!isContainerReady)
{
var result = await client.Containers.RunCommandInContainerAsync(createdContainer.ID, "pg_isready -U postgres");
if (result.stdout.TrimEnd('\n') == $"/var/run/postgresql:{configuration.ContainerPort} - accepting connections")
{
isContainerReady = true;
}
}
var store = DocumentStore.For($"host=localhost;" +
$"database={configuration.DatabaseName};" +
$"username={configuration.Username};" +
$"password={configuration.Password}");
// Whatever else needs to be done...
}
}
扩展名在ContainerOperationsExtensions.cs中定义：
using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;
using Docker.DotNet;
using Docker.DotNet.Models;
namespace Benchmark.DockerClient
{
public static class ContainerOperationsExtensions
{
public static async Task<IList<ContainerListResponse>> SearchByNameAsync(this IContainerOperations source, string name, bool all = true)
{
return await source.ListContainersAsync(new ContainersListParameters
{
All = all,
Filters = new Dictionary<string, IDictionary<string, bool>>
{
{"name", new Dictionary<string, bool>
{
{name, true}
}
}
}
});
}
public static async Task StopAndRemoveContainerAsync(this IContainerOperations source, string containerId)
{
await source.StopContainerAsync(containerId, new ContainerStopParameters());
await source.RemoveContainerAsync(containerId, new ContainerRemoveParameters());
}
public static async Task<CreateContainerResponse> RunContainerAsync(this IContainerOperations source, CreateContainerParameters parameters)
{
var createdContainer = await source.CreateContainerAsync(parameters);
await source.StartContainerAsync(createdContainer.ID, new ContainerStartParameters());
return createdContainer;
}
public static async Task<(string stdout, string stderr)> RunCommandInContainerAsync(this IContainerOperations source, string containerId, string command)
{
var commandTokens = command.Split(" ", StringSplitOptions.RemoveEmptyEntries);
var createdExec = await source.ExecCreateContainerAsync(containerId, new ContainerExecCreateParameters
{
AttachStderr = true,
AttachStdout = true,
Cmd = commandTokens
});
var multiplexedStream = await source.StartAndAttachContainerExecAsync(createdExec.ID, false);
return await multiplexedStream.ReadOutputToEndAsync(CancellationToken.None);
}
}
}
Docker.cs以获取本地docker api uri：
using System;
using System.Runtime.InteropServices;
namespace Benchmark.DockerClient
{
public static class Docker
{
static Docker()
{
DefaultLocalApiUri = RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
? new Uri("npipe://./pipe/docker_engine")
: new Uri("unix:/var/run/docker.sock");
}
public static Uri DefaultLocalApiUri { get; }
}
}
答案 0 :(得分：2)
我建议您使用自定义healtcheck来检查数据库是否准备好接受连接。
我不熟悉Docker的.NET客户端，但是以下docker run命令显示了您应该尝试的操作：
docker run --name postgres \
--health-cmd='pg_isready -U postgres' \
--health-interval='10s' \
--health-timeout='5s' \
--health-start-period='10s' \
postgres:latest
时间参数应根据您的需要进行更新。
配置了此healtcheck后，您的应用程序必须等待容器处于“ 健康”状态，然后才能尝试连接数据库。在这种情况下，状态为“ 健康”表示命令pg_isready -U postgres成功执行（因此数据库已准备好接受连接）。
可以通过以下方式检索容器的状态：
docker inspect --format "{{json .State.Health.Status }}" postgres