How to use ActionFilter on Prometheus mapPath in standard .Net Web API? - asp.net-web-api

Question

I want to filter the range of client IPs who can route to Prometheus metrics.
So in startup I have
public void Configuration(IAppBuilder app)
{
ConfigureAuth(app);
app.UsePrometheusServer(q =>
{
q.MapPath = "/metrics";
});
app.UseWebApi(config);
}
And this is my custom actionFilter class
public class IpFilter : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext actionContext)
{
string clinetIP = GetClientIpAddress(actionContext.HttpContext.Items["MS_HttpRequestMessage"] as HttpRequestMessage);
if (IpAllowed(clinetIP))
base.OnActionExecuting(actionContext);
}
But I have no idea how to use IpFilter since it cannot be use as an attribute on a controller action.
I tried to use it by adding a middleware using owin but the next.Invoke doesn't work properly
public void Configuration(IAppBuilder app)
{
app.Map("/metrics", metricsApp =>
{
metricsApp.Use<TestIpMid>(deniedIps);
metricsApp.UsePrometheusServer(q => q.MapPath = "/metrics");
});
app.UsePrometheusServer(q =>
{
q.MapPath = "/metrics";
});
app.UseWebApi(config);
}
and this is the middleware:
public class TestIpMid : OwinMiddleware
{
private readonly HashSet<string> _deniedIps;
public TestIpMid(OwinMiddleware next, HashSet<string> deniedIps) : base(next)
{
_deniedIps = deniedIps;
}
public override async Task Invoke(IOwinContext context)
{
var ipAddress = context.Request.RemoteIpAddress;
if (_deniedIps.Contains(ipAddress))
{
context.Response.StatusCode = 403;
return;
}
await Next.Invoke(context);
}
}
please help me :'(

Answer 1

this solution worked for me but other ways I was thinking of didn't work
public void Configuration(IAppBuilder app)
{
ConfigureAuth(app);
var config = new HttpConfiguration();
var allowedIps = ProtectedSettings.Read(ProtectedSettings.protheusIpWhitelist).Split(new string[] { "," }, StringSplitOptions.RemoveEmptyEntries);
app.Use(async (Context, next) =>
{
var ipAddress = Context.Request.RemoteIpAddress;
if ((!allowedIps.Contains(ipAddress)) && Context.Request.Path.Value == "/metrics")
{
Context.Response.StatusCode = 403;
return;
}
await next.Invoke();
});
app.UsePrometheusServer(q =>
{
q.MapPath = "/metrics";
});
app.UseWebApi(config);
}