Is it possible to increase CloudFlare time-out? - timeout

Is it possible to increase CloudFlare's time-out? If yes, how?
My code takes a while to execute and I wasn't planning on Ajaxifying it the coming days.

No, CloudFlare only offers that kind of customisation on Enterprise plans.
CloudFlare will time out if it fails to establish a HTTP handshake after 15 seconds.
CloudFlare will also wait 100 seconds for a HTTP response from your server before you will see a 524 timeout error.
Other than this there can be timeouts on your origin web server.
It sounds like you need Inter-Process Communication. HTTP should not be used a mechanism for performing blocking tasks without sending responses, these kind of activities should instead be abstracted away to a non-HTTP service on the server. By using RabbitMQ (or any other MQ) you can then pass messages from the HTTP element of your server over to the processing service on your webserver.

I was in communication with Cloudflare about the same issue, and also with the technical support of RabbitMQ.
RabbitMQ suggested using Web Stomp which relies on Web Sockets. However Cloudflare suggested...
Websockets would create a persistent connection through Cloudflare and
there's no timeout as such, but the best way of resolving this would
be just to process the request in the background and respond asynchronously, and serve a 'Loading...' page or similar, rather than having the user to wait for 100 seconds. That would also give a better user experience to the user as well
UPDATE:
For completeness, I will also record here that
I also asked CloudFlare about running the report via a subdomain and "grey-clouding" it and they replied as follows:
I will suggest to verify on why it takes more than 100 seconds for the
reports. Disabling Cloudflare on the sub-domain, allow attackers to
know about your origin IP and attackers will be attacking directly
bypassing Cloudflare.
FURTHER UPDATE
I finally solved this problem by running the report using a thread and using AJAX to "poll" whether the report had been created. See Bypassing CloudFlare's time-out of 100 seconds

Cloudflare doesn't trigger 504 errors on timeout
504 is a timeout triggered by your server - nothing to do with Cloudflare.
524 is a timeout triggered by Cloudflare.
See: https://support.cloudflare.com/hc/en-us/articles/115003011431-Troubleshooting-Cloudflare-5XX-errors#502504error
524 error? There is a workaround:
As #mjsa mentioned, Cloudflare only offers timeout settings to Enterprise clients, which is not an option for most people.
However, you can disable Cloudflare proxing for that specific (sub)domain by turning the orange cloud into grey:
Before:
After:
Note: it will disable extra functionalities for that specific (sub)domain, including IP masking and SSL certificates.
As Cloudflare state in their documentation:
If you regularly run HTTP requests that take over 100 seconds to
complete (for example large data exports), consider moving those
long-running processes to a subdomain that is not proxied by
Cloudflare. That subdomain would have the orange cloud icon toggled to
grey in the Cloudflare DNS Settings . Note that you cannot use a Page
Rule to circumvent Error 524.

I know that it cannot be treated like a solution but there is a 2 ways of avoiding this.
1) Since this timeout is often related to long time generating of something, this type of works can be done through crontab or if You have access to SSH you can run a PHP command directly to execute. In this case connection is not served through Cloudflare so it goes as long as your configuration allows it to run. Check it on Google how to run scripts from command line or how to determine them in crontab by using /usr/bin/php /direct/path/to/file.php
2) You can create subdomain that is not added to cloudlflare and move Your script there and run them directly through URL, Ajax call or whatever.
There is a good answer on Cloudflare community forums about this:
If you need to have scripts that run for longer than around 100 seconds without returning any data to the browser, you can’t run these through Cloudflare. There are a couple of options: Run the scripts via a grey-clouded subdomain or change the script so that it kicks off a long-running background process and quickly returns a status which the browser can poll until the background process has completed, at which point the full response can be returned. This is the way most people do this type of action as keeping HTTP connections open for a long time is unreliable and can be very taxing also.
This topic on Stackoverflow is high in SERPs so I decided to write down this answer for those who will find it usefull.

https://support.cloudflare.com/hc/en-us/articles/115003011431-Troubleshooting-Cloudflare-5XX-errors#502504error
Cloudflare 524 error results from a web page taking more than 100 seconds to completely respond.
This can be overridden to (up to) 600 seconds ... if you change to "Enterprise" Cloudflare account. The cost of Enterprise is roughtly $40k per year (annual contract required).

If you are getting your results with curl, you could use the resolve option to directly access your IP, not using the Cloudflare proxy IP:
For example:
curl --max-time 120 -s -k --resolve lifeboat.com:443:127.0.0.1 -L https://lifeboat.com/blog/feed

The simplest way to do this is to increase your proxy waiting timeout.
If you are using Nginx for instance you can simply add this line in your /etc/nginx/sites-availables/your_domain:
location / {
...
proxy_read_timeout 600s; # this increases it by 10mins; feel free to change as you see fit with your needs.
...
}
If the issue persists, make sure you use let's encrypt to secure your server alongside Nginx and then disable the orange cloud on that specific subdomain on Cloudflare.
Here are some resources you can check to help do that
installing-nginx-on-ubuntu-server
secure-nginx-with-let's-encrypt

Related

iOS - mobile application is sending two this same request in milliseconds apart

In our application we observe multiple ( two ) these same requests send from mobile application to server in milliseconds apart.
As we discuss the problem with dev team, they said they don't send two requests from an application perspective, but on the server-side, we see exactly these same two requests.
Does anybody know if iOS has this type of functionality to keep resending this same request in case of a lost connection or any other case? ( This is milliseconds that server doesn't respond yet )
The application should send only one request, wait for response success/failure, and then resend as needed. So far as we know, there is no logic in the application itself that will trigger sending two requests from the app to the server in milliseconds apart.
Thank you for any suggestions.
It's hard to tell without looking at the code or knowing your network infrastructure.
What I'd suggest to do first is to run the app through a debugging proxy server like Charles, Proxyman or mitmproxy. If it shows multiple requests, most likely the app is to blame, I'd bet on a concurrency bug.
If the debugging proxy shows just one request but your server observes two, you'll have to check your network infrastructure, it might be that some load balancer or reverse proxy is configured incorrectly.

how to limit the number of times Vaadin 14 tries to send heartbeat requests

We have a Vaadin 14 (Flow) application which is fronted by an Apache reverse proxy that integrates with Gluu for authentication using OpenID (mod_auth_openidc).
This is generally working fine, except when users leave their browser open with the application idle for a long time, until the max session time of the OpenID session is reached. The problem is, at that point the Vaadin client keeps trying to send heartbeat requests. This, in combination with this mod_auth_openidc issue, results in state cookies piling up and reaching a limit so that the user has to close her browser before being able to re-login.
I've tried various things (unsuccessfully) in order to get the server to instruct the browser to visit a logout URL when a heartbeat request is received after session timeout (in combination with vaadin.closeIdleSessions=true), but even if it worked it wouldn't be a solution for other browser tabs that may also be open at that time and sending heartbeat requests.
What we really want is to limit the number of times the Vaadin client retries to send the heartbeat requests (say max 3 times) and then just stop sending requests (maybe display a message to re-login).
Is this possible in any way? The current workaround is to disable the heartbeats completely, but this doesn't seem ideal (Vaadin won't detect idle UIs).
The UI instance has a ReconnectDialogConfiguration which includes reconnectAttempts property to control how many times to re-try requests (including heartbeat requests). Default seems to be 10000.
In Vaadin 14 (LTS) this can be set using PageConfigurator.
In Vaadin 18 (latest release) this is done using AppShellConfigurator
Disabling the heartbeats is the way to go. If you need something more nuanced than that, you'll need to make a change (maybe add a configuration option) in how Heartbeats work in Vaadin. Creating a ticket in GitHub could be a good place to start.

Best method to monitor connectivity

Asides from a constant 24/7 ping, how can I monitor a connection status to a site to ensure that it is up.
For example, 192.168.0.1 <-> 192.168.20.1, measuring the connection between these two sites.
I would suggest trying to simulate the usual actions you perform when you are working with the site. For example if the other site is mostly used as a file server I would write a script that will copy files to and from the site. If it is a web server then loading the main page every few minutes is a good idea.For authentication servers logging in is what you want.
Try to think about the most common functionality and simulate it.

How might Apache cause duplicate requests?

I have two Rails apps that talk to one another. A few times a day, requests from app A show up in duplicate (or triplicate/quadruplicate) at app B. All outbound and inbound requests are logged. The logs show that app A is sending one outbound request and that app B receives that request twice or more during the same second.
App B sits behind Apache and an Amazon Elastic Load Balancer.
I am not sure where to look or even what questions to ask to hone in on what might be causing this issue. If you need more data, I would be happy to provide it.
The retries are likely coming out of the Amazon Elastic Load Balancer or some network component (like a router, for example). I've seen similar behavior when using other load balancers (like Citrix NetScaler) as well.
Basically, the request gets an idle timeout at some level in the request chain. If that timeout doesn't send a proper HTTP 5xx status back to the client (for example it could just silently close the connection) then any components between the source of the timeout and the client can potentially decide to retry the request depending on how they are configured.
Tracking down which components cause the retries can be very challenging. My recommendation is to make sure your Rails applications always respond quickly to each other. If the requests can't complete quickly, consider perhaps a background/polling solution or a non-HTTP communication method (WebSockets for example).

How to check the cause for a HTTP request latency/waiting time?

I issue a simple GET request to my server, and it's coming back after ~1.2 seconds on average (using firebug NET tab, the "waiting for reqponse" part- not even the whole reponse time)
My ping to the server is 0.250
Using Passenger with rails 2.3.3, in the rails log the request is taking ~0.023
My server is on GoDaddy, so I checked their homepage with firebug also- the "waiting for reqponse" time for their page is ~0.320
Worst case should be around 0.4... so where did I lose the other 0.8 seconds?
What else can I check?
Edit:
Seems like it's unrelated to rails-
An image request (that only apache responds to, doest hit the rails at all) takes ~1.2 seconds also
GoDaddy may have a reverse-proxy between you and your HTTP server.
They may be doing something like sending you the response headers right away, then possibly serving you the contents of the response from cache.
So, from the standpoint of your HTTP server, the response is transmitted. Then it goes to GoDaddy's reverse-proxy, then finally to your web browser.
Try setting PassengerPoolIdleTime to 0 in your Servers or VHosts configuration.
Maybe your server is shutting down the application instances to fast and spawns a new instance with every request which usualy takes quite long.
Take a look at the documentation for more information on this setting:
http://modrails.com/documentation/Users%20guide%20Apache.html#PassengerPoolIdleTime
Where your files are hosted from for GoDaddy is not the same as where their homepage is hosted from.
Have you checked other pages you have hosted on the same server? Possibly due to database connections or "slow" connections like that can cause the page to take awhile before it's sent back to the client.
Doesn't sound like it is your problem, but the ISP's.
Can you do a wget to an internal ip/port to your rails app directly (or apache) from the same server?
That will tell you if the probaby is in the app stack or further upstream.
If you can, you can use apache tool, called ab "apache benchmark" to help.
The key is having a ssh access to your computer.

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