Veggerby.Ignition.Http 0.6.0

Veggerby.Ignition.Http

HTTP readiness signals for Veggerby.Ignition - verify HTTP endpoints and external services during application startup.

Installation

dotnet add package Veggerby.Ignition.Http

Usage

Basic HTTP Endpoint Verification

builder.Services.AddIgnition();

builder.Services.AddHttpReadiness("https://api.example.com/health");

var app = builder.Build();
await app.Services.GetRequiredService<IIgnitionCoordinator>().WaitAllAsync();

With Custom Status Codes

builder.Services.AddHttpReadiness(
    "https://api.example.com/health",
    options =>
    {
        options.ExpectedStatusCodes = [200, 204];
        options.Timeout = TimeSpan.FromSeconds(5);
    });

With Response Validation

builder.Services.AddHttpReadiness(
    "https://api.example.com/health",
    options =>
    {
        options.ExpectedStatusCodes = [200];
        options.ValidateResponse = async (response) =>
        {
            var content = await response.Content.ReadAsStringAsync();
            return content.Contains("healthy");
        };
        options.Timeout = TimeSpan.FromSeconds(10);
    });

With Custom Headers

builder.Services.AddHttpReadiness(
    "https://api.example.com/health",
    options =>
    {
        options.CustomHeaders = new Dictionary<string, string>
        {
            ["Authorization"] = "Bearer token123",
            ["User-Agent"] = "MyApp/1.0"
        };
    });

JSON Response Validation

builder.Services.AddHttpReadiness(
    "https://api.example.com/health",
    options =>
    {
        options.ValidateResponse = async (response) =>
        {
            var json = await response.Content.ReadAsStringAsync();
            using var doc = JsonDocument.Parse(json);
            return doc.RootElement.GetProperty("status").GetString() == "healthy";
        };
    });

Features

• HTTP Endpoint Verification: Validates connectivity to external HTTP services
• Flexible Status Code Matching: Support for multiple expected status codes (200, 204, etc.)
• Custom Response Validation: Validate response body content (JSON, text, etc.)
• Custom Headers: Add Authorization, User-Agent, or other headers
• Activity Tracing: Tags for URL, status codes, and validation results
• Structured Logging: Information, Debug, and Error level diagnostics
• HttpClient Reuse: Efficient connection reuse via IHttpClientFactory
• Idempotent Execution: Cached results prevent redundant requests
• Thread-Safe: Concurrent readiness checks execute once

Configuration Options

Logging

The signal emits structured logs at different levels:

• Information: Request start and successful completions
• Debug: Response received, validation execution
• Error: Status code mismatches, validation failures, connection errors

Activity Tracing

When tracing is enabled, the signal adds these tags:

• http.url: Target URL
• http.expected_status_codes: Comma-separated expected status codes
• http.status_code: Actual response status code
• http.custom_validation: "true" if custom validation is configured

Examples

Health Check Integration

builder.Services.AddIgnition();
builder.Services.AddHttpReadiness("https://api.example.com/health");

builder.Services
    .AddHealthChecks()
    .AddCheck<IgnitionHealthCheck>("ignition-readiness");

Multiple External Services

// Primary API
builder.Services.AddHttpReadiness(
    "https://api.example.com/health",
    options =>
    {
        options.Timeout = TimeSpan.FromSeconds(5);
    });

// Payment Gateway
builder.Services.AddHttpReadiness(
    "https://payment.example.com/status",
    options =>
    {
        options.ExpectedStatusCodes = [200, 204];
        options.Timeout = TimeSpan.FromSeconds(10);
    });

Note: Currently, multiple HTTP signals will share the same name ("http-readiness"). For distinct signals, implement custom IIgnitionSignal with unique names.

Retry-After Header Handling

The signal does not automatically respect Retry-After headers. For retry logic, use Polly or similar libraries with the coordinator's timeout policies:

builder.Services.AddIgnition(options =>
{
    options.Policy = IgnitionPolicy.BestEffort;
    options.GlobalTimeout = TimeSpan.FromSeconds(30);
});

Error Handling

Connection failures and validation errors are logged and propagated:

try
{
    await coordinator.WaitAllAsync();
}
catch (AggregateException ex)
{
    foreach (var inner in ex.InnerExceptions)
    {
        if (inner is HttpRequestException httpEx)
        {
            // Handle HTTP-specific errors
            Console.WriteLine($"HTTP Error: {httpEx.Message}");
        }
        else if (inner is InvalidOperationException validationEx)
        {
            // Handle validation failures
            Console.WriteLine($"Validation Error: {validationEx.Message}");
        }
    }
}

Performance

• Efficient HttpClient reuse via IHttpClientFactory
• Minimal allocations per signal invocation
• Async throughout (no blocking I/O)
• Idempotent execution (request made once)

License

MIT License. See LICENSE.