extension/WebJobs.Extensions.RabbitMQ/Config/RabbitMQExtensionConfigProvider.cs

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the MIT License. See License.txt in the project root for license information.

using System;
using System.Collections.Concurrent;
using System.Text;
using Microsoft.Azure.WebJobs.Description;
using Microsoft.Azure.WebJobs.Host;
using Microsoft.Azure.WebJobs.Host.Bindings;
using Microsoft.Azure.WebJobs.Host.Config;
using Microsoft.Azure.WebJobs.Logging;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;

namespace Microsoft.Azure.WebJobs.Extensions.RabbitMQ;

[Extension("RabbitMQ")]
internal class RabbitMQExtensionConfigProvider(IOptions<RabbitMQOptions> options, INameResolver nameResolver, IRabbitMQServiceFactory rabbitMQServiceFactory, ILoggerFactory loggerFactory, IConfiguration configuration, IDrainModeManager drainModeManager) : IExtensionConfigProvider
{
    private readonly IOptions<RabbitMQOptions> options = options;
    private readonly INameResolver nameResolver = nameResolver;
    private readonly IRabbitMQServiceFactory rabbitMQServiceFactory = rabbitMQServiceFactory;
    private readonly ILogger logger = loggerFactory?.CreateLogger(LogCategories.CreateTriggerCategory("RabbitMQ"));
    private readonly IConfiguration configuration = configuration;
    private readonly ConcurrentDictionary<string, IRabbitMQService> connectionParametersToService = new();
    private readonly IDrainModeManager drainModeManager = drainModeManager;

    public void Initialize(ExtensionConfigContext context)
    {
        _ = context ?? throw new ArgumentNullException(nameof(context));

#pragma warning disable 0618
        FluentBindingRule<RabbitMQAttribute> rule = context.AddBindingRule<RabbitMQAttribute>();
#pragma warning restore 0618

        rule.BindToCollector((attr) =>
        {
            return new RabbitMQAsyncCollector(this.CreateContext(attr), this.logger);
        });
        rule.BindToInput(new RabbitMQClientBuilder(this, this.options));
        rule.AddConverter<string, ReadOnlyMemory<byte>>(arg => Encoding.UTF8.GetBytes(arg));
        rule.AddConverter<byte[], ReadOnlyMemory<byte>>(arg => arg);
        rule.AddOpenConverter<OpenType.Poco, ReadOnlyMemory<byte>>(typeof(PocoToBytesConverter<>));

#pragma warning disable 0618
        FluentBindingRule<RabbitMQTriggerAttribute> triggerRule = context.AddBindingRule<RabbitMQTriggerAttribute>();
#pragma warning restore 0618

        // More details about why the BindToTrigger was chosen instead of BindToTrigger<BasicDeliverEventArgs> detailed here https://github.com/Azure/azure-functions-rabbitmq-extension/issues/110
        triggerRule.BindToTrigger(new RabbitMQTriggerAttributeBindingProvider(
                this.nameResolver,
                this,
                this.logger,
                this.options,
                this.configuration,
                this.drainModeManager));
    }

    internal RabbitMQContext CreateContext(RabbitMQAttribute attribute)
    {
        string connectionString = Utility.FirstOrDefault(attribute.ConnectionStringSetting, this.options.Value.ConnectionString);
        string queueName = Utility.FirstOrDefault(attribute.QueueName, this.options.Value.QueueName);
        bool disableCertificateValidation = Utility.FirstOrDefault(attribute.DisableCertificateValidation, this.options.Value.DisableCertificateValidation);

        var resolvedAttribute = new RabbitMQAttribute
        {
            ConnectionStringSetting = connectionString,
            QueueName = queueName,
            DisableCertificateValidation = disableCertificateValidation,
        };

        IRabbitMQService service = this.GetService(connectionString, queueName, disableCertificateValidation);

        return new RabbitMQContext
        {
            ResolvedAttribute = resolvedAttribute,
            Service = service,
        };
    }

    internal IRabbitMQService GetService(string connectionString, string queueName, bool disableCertificateValidation)
    {
        string[] keyArray =
            [connectionString, queueName, disableCertificateValidation.ToString()];
        string key = string.Join(",", keyArray);
        return this.connectionParametersToService.GetOrAdd(key, _ => this.rabbitMQServiceFactory.CreateService(connectionString, queueName, disableCertificateValidation));
    }

    // Overloaded method used only for getting the RabbitMQ client.
    internal IRabbitMQService GetService(string connectionString, bool disableCertificateValidation)
    {
        string[] keyArray =
            [connectionString, disableCertificateValidation.ToString()];
        string key = string.Join(",", keyArray);
        return this.connectionParametersToService.GetOrAdd(key, _ => this.rabbitMQServiceFactory.CreateService(connectionString, disableCertificateValidation));
    }
}