115 lines
3.7 KiB
C#
115 lines
3.7 KiB
C#
using System;
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using System.Data.Common;
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using System.Linq;
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using System.Net;
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using System.Net.Sockets;
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using System.Threading;
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using Newtonsoft.Json;
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using Npgsql;
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using StackExchange.Redis;
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namespace Worker
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{
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public class Program
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{
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public static int Main(string[] args)
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{
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try
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{
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var pgsql = OpenDbConnection("Server=db;Username=postgres;");
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var redis = OpenRedisConnection("redis").GetDatabase();
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var definition = new { vote = "", voter_id = "" };
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while (true)
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{
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string json = redis.ListLeftPopAsync("votes").Result;
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if (json != null)
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{
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var vote = JsonConvert.DeserializeAnonymousType(json, definition);
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Console.WriteLine($"Processing vote for '{vote.vote}' by '{vote.voter_id}'");
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UpdateVote(pgsql, vote.voter_id, vote.vote);
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}
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}
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}
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catch (Exception ex)
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{
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Console.Error.WriteLine(ex.ToString());
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return 1;
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}
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}
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private static NpgsqlConnection OpenDbConnection(string connectionString)
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{
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var connection = new NpgsqlConnection(connectionString);
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while (true)
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{
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try
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{
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connection.Open();
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break;
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}
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catch (DbException)
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{
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Console.Error.WriteLine("Failed to connect to db - retrying");
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}
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}
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var command = connection.CreateCommand();
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command.CommandText = @"CREATE TABLE IF NOT EXISTS votes (
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id VARCHAR(255) NOT NULL UNIQUE,
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vote VARCHAR(255) NOT NULL
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)";
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command.ExecuteNonQuery();
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return connection;
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}
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private static ConnectionMultiplexer OpenRedisConnection(string hostname)
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{
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// Use IP address to workaround hhttps://github.com/StackExchange/StackExchange.Redis/issues/410
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var ipAddress = GetIp(hostname);
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Console.WriteLine($"Found redis at {ipAddress}");
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while (true)
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{
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try
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{
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return ConnectionMultiplexer.Connect(ipAddress);
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}
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catch (RedisConnectionException)
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{
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Console.Error.WriteLine("Failed to connect to redis - retrying");
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Thread.Sleep(1000);
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}
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}
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}
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private static string GetIp(string hostname)
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=> Dns.GetHostEntryAsync(hostname)
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.Result
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.AddressList
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.First(a => a.AddressFamily == AddressFamily.InterNetwork)
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.ToString();
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private static void UpdateVote(NpgsqlConnection connection, string voterId, string vote)
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{
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var command = connection.CreateCommand();
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try
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{
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command.CommandText = "INSERT INTO votes (id, vote) VALUES (@id, @vote)";
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command.Parameters.AddWithValue("@id", voterId);
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command.Parameters.AddWithValue("@vote", vote);
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command.ExecuteNonQuery();
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}
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catch (DbException)
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{
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command.CommandText = "UPDATE votes SET vote = @vote WHERE id = @id";
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command.ExecuteNonQuery();
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}
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finally
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{
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command.Dispose();
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}
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}
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}
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} |