Why is my ASP.NET Core Web API not connecting to Elastic Cache Valkey

Question

I am working on an ASP.NET Core Web API that is deployed to AWS. I am trying to integrate Elastic Cache using Valkey and working locally at the moment. This is my Program.cs:

using Amazon;
using Amazon.S3;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.EntityFrameworkCore;
using Microsoft.IdentityModel.Tokens;
using Microsoft.OpenApi.Models;
using smart_qualify_api.Entities;
using smart_qualify_api.Services.ResumeTemplates;
using StackExchange.Redis;
using System.Security.Authentication;
using System.Text;

var builder = WebApplication.CreateBuilder(args);
var config = builder.Configuration;

// In Program.cs, after other service configurations
builder.Services.AddSingleton<IConnectionMultiplexer>(sp =>
{
    var config = builder.Configuration;
    var valkeyEndpoint = config["ElastiCache:ValkeyEndpoint"]!;
    var useSsl = bool.Parse(config["ElastiCache:UseSsl"] ?? "false");

    var redisConfig = new ConfigurationOptions
    {
        EndPoints = { valkeyEndpoint },
        Ssl = useSsl,
        AbortOnConnectFail = false, // Prevent app from crashing if connection fails
        ConnectTimeout = 30000, // Timeout in milliseconds
        SyncTimeout = 10000,    // 10 seconds for commands
        SslProtocols = SslProtocols.Tls12 | SslProtocols.Tls13, // Explicitly allow modern TLS versions
    };

    return ConnectionMultiplexer.Connect(redisConfig);
});

builder.Services.AddSingleton<IAmazonS3>(sp => new AmazonS3Client(RegionEndpoint.AFSouth1));
// Add services to the container.
builder.Services.AddControllers();
// Add IHttpClientFactory
builder.Services.AddHttpClient();
// Add Template Registry
builder.Services.AddSingleton<TemplateRegistry>();
// Add CV Analysis Service
builder.Services.AddScoped<smart_qualify_api.Services.CVAnalysisService>();
// Add Push Notification Service
builder.Services.AddScoped<smart_qualify_api.Services.PushNotificationService>();

builder.Services.AddCors(options =>
{
    options.AddPolicy("AllowNextJsFrontend", builder =>
    {
        builder.AllowAnyOrigin()
        .AllowAnyHeader()
        .AllowAnyMethod();
    });
});

// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();

builder.Services.AddAuthentication(options =>
{
    options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
    options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
    options.DefaultScheme = JwtBearerDefaults.AuthenticationScheme;

}).AddJwtBearer(options =>
{
    options.RequireHttpsMetadata = false;
    options.SaveToken = true;
    options.TokenValidationParameters = new TokenValidationParameters
    {
        ValidateIssuer = true,
        ValidateAudience = true,
        ValidateLifetime = true,
        ValidateIssuerSigningKey = true,
        ValidIssuer = config["Jwt:Issuer"],
        ValidAudience = config["Jwt:Audience"],
        IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(config["Jwt:Token"]!))
    };
});
builder.Services.AddAuthorization();

builder.Services.AddSwaggerGen(swagger =>
{
    swagger.SwaggerDoc("v1", new OpenApiInfo { Version = "v1" });

    swagger.AddSecurityDefinition("Bearer", new OpenApiSecurityScheme()
    {
        Name = "Authorization",
        Type = SecuritySchemeType.Http,
        Scheme = JwtBearerDefaults.AuthenticationScheme,
        BearerFormat = "JWT",
        In = ParameterLocation.Header,
        Reference = new OpenApiReference
        {
            Id = JwtBearerDefaults.AuthenticationScheme,
            Type = ReferenceType.SecurityScheme,
        }
    });

    swagger.AddSecurityRequirement(new OpenApiSecurityRequirement
    {
        {
            new OpenApiSecurityScheme
            {
                Reference = new OpenApiReference
                {
                    Type = ReferenceType.SecurityScheme,
                    Id = "Bearer"
                }
            }, Array.Empty<string>()
        }
    });
});

builder.Services.AddAuthorizationBuilder().AddPolicy("AdminUserPolicy", options =>
{
    options.RequireAuthenticatedUser();
    options.RequireRole("admin", "user", "student");
}).AddPolicy("AdminPolicy", options =>
{
    options.RequireAuthenticatedUser();
    options.RequireRole("admin");
}).AddPolicy("UserPolicy", options =>
{
    options.RequireAuthenticatedUser();
    options.RequireRole("user", "student");
});

builder.Services.AddDbContext<SMQDbContext>(options =>
{
    options.UseNpgsql(builder.Configuration.GetConnectionString("DefaultConnection"));
});

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseSwagger();
    app.UseSwaggerUI();
}

//app.UseHttpsRedirection();
app.UseCors("AllowNextJsFrontend");
app.UseAuthentication();
app.UseAuthorization();
app.MapControllers();

app.Run();

And this is my controller to access the templates:

using Amazon.S3;
using Amazon.S3.Model;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using QuestPDF.Infrastructure;
using smart_qualify_api.Entities;
using smart_qualify_api.Models.Resume;
using smart_qualify_api.Services.ResumeTemplates;
using StackExchange.Redis;
using System.Security.Claims;
using System.Text.Json;

namespace smart_qualify_api.Controllers.Core
{
    [Route("api/[controller]")]
    [ApiController]
    [ApiExplorerSettings(IgnoreApi = false)]
    public class ResumeController : ControllerBase
    {
        private readonly SMQDbContext _dbContext;
        private readonly IConfiguration _config;
        private readonly TemplateRegistry _templateRegistry;
        private readonly IHttpClientFactory _httpClientFactory;
        private readonly IAmazonS3 _s3Client;
        private readonly IConnectionMultiplexer _redis; // Add Redis connection
        private readonly string _bucketName = "smart-qualify-assets";
        private readonly string _resumeFolder = "user-resumes/";
        private readonly string _cacheKey = "resume_templates"; // Cache key for templates
        private readonly TimeSpan _cacheTTL = TimeSpan.FromMinutes(30); // Cache expiration

        public ResumeController(
            SMQDbContext dbContext,
            IConfiguration config,
            TemplateRegistry templateRegistry,
            IHttpClientFactory httpClientFactory,
            IAmazonS3 s3Client,
            IConnectionMultiplexer redis // Inject Redis
            )
        {
            _dbContext = dbContext;
            _config = config;
            _templateRegistry = templateRegistry;
            _httpClientFactory = httpClientFactory;
            _s3Client = s3Client;
            _redis = redis; // Initialize Redis
        }

        [HttpGet("getResumeTemplates")]
        [Authorize]
        public IActionResult GetResumeTemplates()
        {
            try
            {
                // Get Redis database
                var db = _redis.GetDatabase();

                // Try to get templates from cache
                var cachedTemplates = db.StringGet(_cacheKey);

                if (cachedTemplates.HasValue)
                {
                    // Deserialize cached templates
                    var templates = JsonSerializer.Deserialize<List<object>>(cachedTemplates!);
                    return Ok(new { success = true, templates });
                }

                // Cache miss: Fetch templates from TemplateRegistry
                var templatesFromRegistry = _templateRegistry.GetAllTemplates()
                    .Select(t => new { templateId = t.TemplateId, name = t.Name, templateImageUrl = t.TemplateImageUrl })
                    .ToList();

                // Serialize and store in cache with TTL
                var serializedTemplates = JsonSerializer.Serialize(templatesFromRegistry);
                db.StringSet(_cacheKey, serializedTemplates, _cacheTTL);

                return Ok(new { success = true, templates = templatesFromRegistry });
            }
            catch (RedisException ex)
            {
                // Handle Redis errors (e.g., connection issues)
                // Fallback to fetching from TemplateRegistry without caching
                var templates = _templateRegistry.GetAllTemplates()
                    .Select(t => new { templateId = t.TemplateId, name = t.Name, templateImageUrl = t.TemplateImageUrl })
                    .ToList();
                return Ok(new { success = true, templates });
            }
            catch (Exception ex)
            {
                // Handle other errors
                return StatusCode(500, new { success = false, message = "Error retrieving resume/cv templates.", Error = ex.Message });
            }
        }
}

These are my appsettings:

{
  "ConnectionStrings": {
    //"DefaultConnection": "Server=.\\SQLEXPRESS; Database=SmartQualifyDb; Trusted_Connection=True; TrustServerCertificate=true;",
    //"DefaultConnection": "Server=awseb-e-dimv4pgcpg-stack-awsebrdsdatabase-t9atez32kzzv.cxgqqkemg9gv.af-south-1.rds.amazonaws.com; Database=SmartQualifyDEV; User Id=smartqualifydev; Password={mypassword}; TrustServerCertificate=true; Encrypt=False;"
    "DefaultConnection": "Host=awseb-e-tmpi2juhkc-stack-awsebrdsdatabase-xnd8m1nnlxta.cxgqqkemg9gv.af-south-1.rds.amazonaws.com;Port=5432;Database=SmartQualifyDEV;Username=postgres;Password={mypassword};SslMode=Require;"
  },
  "Jwt": {
    "Token": "{mytoken}",
    "Issuer": "https://localhost:7292/",
    "Audience": "https://localhost:7292/"
  },
  "OpenAI": {
    "ApiKey": "your-openai-api-key-here"
  },
  "Firebase": {
    "ServerKey": "your-firebase-server-key-here"
  },
  "ElastiCache": {
    "ValkeyEndpoint": "smartqualif-esmt7q.serverless.afs1.cache.amazonaws.com:6379",
    "UseSsl": true
  },
  "MailOptions": {

  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*"
}

I get an error when I run the endpoint:

RedisConnectionException: It was not possible to connect to the redis server(s) smartqualify-esmt7q.serverless.afs1.cache.amazonaws.com:6379/Interactive. ConnectTimeout

StackExchange.Redis.RedisConnectionException: 'The message timed out in the backlog attempting to send because no connection became available (10000ms) - Last Connection Exception: It was not possible to connect to the redis server(s) smartqualify-esmt7q.serverless.afs1.cache.amazonaws.com:6379/Interactive. ConnectTimeout, command=GET, timeout: 10000, inst: 0, qu: 1, qs: 0, aw: False, bw: SpinningDown, rs: NotStarted, ws: Initializing, in: 0, last-in: 0, cur-in: 0, sync-ops: 3, async-ops: 0, serverEndpoint: smartqualify-esmt7q.serverless.afs1.cache.amazonaws.com:6379, conn-sec: n/a, aoc: 0, mc: 1/1/0, mgr: 10 of 10 available, clientName: SIYANDA(SE.Redis-v2.9.17.8862), IOCP: (Busy=0,Free=1000,Min=1,Max=1000), WORKER: (Busy=1,Free=32766,Min=12,Max=32767), POOL: (Threads=5,QueuedItems=0,CompletedItems=1681,Timers=5), v: 2.9.17.8862 (Please take a look at this article for some common client-side issues that can cause timeouts: https://stackexchange.github.io/StackExchange.Redis/Timeouts)'

What I expect is being able to access Valkey and store the cached data there from access, and then retrieve the data when I run the getAllTemplates endpoint again.Any possible solution or help would be greatly appreciated

Hey There!. Have you checked that your program has access to the elasticache via IAM permission ? Maybe that is the problem. — Saleh
– Saleh, Commented Sep 11 at 20:56
Hi @Saleh I have been debugging and what I found is that when I deployed my api to elasticbeanstalk the endpoint works well with ElasticCache, and it only doesn't connect when I am running localhost. Is there a way I could run this with localhost? On a production environment it works and it caches well, I also want to do so on a dev environment with localhost — Smart Qualilfy
– Smart Qualilfy, Commented Sep 11 at 22:59

Smart Qualilfy · Accepted Answer · 2025-09-12 12:24:18Z

0

I managed to come up with a solution, AWS ElastiCache seems like it doesn't support localhost so I ran the api with a docker container so we can setup valkey, and it works like a charm, it also didn't affect the deployed api which is great.

answered Sep 12 at 12:24

Smart Qualilfy

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