If the processing of an email fails (eg. API timeout) should I return a 500 (404 ?) or throw an Exception.
Whilst it's undocumented I'm assuming that AppEngine with behave similarly to task queues and retry the http call to deliver the email. Is this a reasonable assumption?
Since the mail system uses webhooks and interacts with App Engine at the HTTP level, your only option is to return an error status. If you throw an exception, your framework will convert this into a 500 response. That's a legitimate way to return a 500 - so how you do this is up to you.
Related
I am using fetch in a NodeJS application. Technically, I have a ReactJS front-end calling the NodeJS backend (as a proxy), and then the proxy calls out to backend services on a different domain.
However, from logging errors from consumers (I haven't been able to reproduce this issue myself) I see that a lot of these proxy calls (using fetch) throw an error that just says Network Request Failed, which is of no help. Some context:
This only occurs on a subset of all total calls (lets say 5% of traffic)
Users that encounter this error can often make the same call again some time later (next couple minutes/hours/days) and it will go through
From Application Insights, I can see no correlation between browsers, locations, etc
Calls often return fast, like < 100 ms
All calls are HTTPS, non are HTTP
We have a fetch polyfill from fetch-ponyfill that will take over if fetch is not available (Internet Explorer). I did test this package itself and the calls went through fine. I also mentioned that this error does occur on browsers that do support fetch, so I don't think this is the error.
Fetch settings for all requests
Method is set per request, but I've seen it fail on different types (GET, POST, etc)
Mode is set to 'same-origin'. I thought this was odd, since we were sending a request from one domain to another, but I tried to set it differently and it didn't affect anything. Also, why would some requests work for some, but not for others?
Body is set per request, based on the data being sent.
Headers is usually just Accept and Content-Type, both set to JSON.
I have tried researching this topic before, but most posts I found referenced React native applications running on iOS, where you have to set some security permissions in the plist file to allow HTTP requests or something to do with transport security.
I have implement logging specific points for the data in Application Insights, and I can see that fetch() was called, but then() was never reached; it went straight to the .catch(). So it's not even reaching code that parses the request, because apparently no request came back (we then parse the JSON response and call other functions, but like I said, it doesn't even reach this point).
Which is also odd, since the request never comes back, but it fails (often) within 100 ms.
My suspicions:
Some consumers have some sort of add-on for there browser that is messing with the request. Although, I run with uBlock Origin and HTTPS Everywhere and I have not seen this error. I'm not sure what else could be modifying requests that would cause it to immediately fail.
The call goes through, which then reaches an Azure Application Gateway, which might fail for some reason (too many connected clients, not enough ports, etc) and returns a response that immediately fails the fetch call without running the .then() on the response.
For #2, I remember I had traced a network call that failed and returned Network Request Failed: Made it through the proxy -> made it through the Application Gateway -> hit the backend services -> backend services sent a response. I am currently requesting access to backend service logs in order to verify this on some more recent calls (last time I did this, I did it through a screenshare with a backend developer), and hopefully clear up the path back to the client (the ReactJS application). I do remember though that it made it to the backend services successfully.
So I'm honestly not sure what's going on here. Does anyone have any insight?
Based on your excellent description and detective work, it's clear that the problem is between your Node app and the other domain. The other domain is throwing an error and your proxy has no choice but to say that there's an error on the server. That's why it's always throwing a 500-series error, the Network Request Failed error that you're seeing.
It's an intermittent problem, so the error is inconsistent. It's a waste of your time to continue to look at the browser because the problem will have been created beyond that, either in your proxy translating that request or on the remote server. You have to find that error.
Here's what I'd do...
Implement brute-force logging in your Node app. You can use Bunyan, or Winston or just require(fs) and write out to some file when an error occurs. Then look at the results. Only log it out when the response code from the other server is in the 400 or 500 ranges. Log the request object and the response object.
Something like this with Bunyan:
fetch(urlToRemoteServer)
.then(res => res.json())
.then(res => whateverElseYoureDoing(res))
.catch(err => {
// Get the request & response to the remote server
log.info({request: req, response: res, err: err});
});
where the res in this case is the response we just got from the other domain and req is our request to them.
The logs on your Azure server will then have the entire request and response. From this you can find commonalities. and (🤞) the cause of the problem.
I have pretty simple LA that contains just 3 actions. It has HTTP trigger, then it gets some data from SQL server and returns http response with SQL data.
Sometimes, it takes 30-50 seconds to get data from SQL but Logic App in the meantime responses with Timeout error to caller.
The execution of template action 'Response_2' is failed: the client application timed out waiting for a response from service. This means that workflow took longer to respond than the alloted timeout value. The connection maintained between the client application and service will be closed and client application will get an HTTP status code 504 Gateway Timeout.
Any idea how to increase allowed time for response?
You can turn on the Asynchronous Response in the Settings of the Response action:
When you run your logic app longer than its time limit, you will accept 202 HTTP Code first:
It will return a response contains location header:
You can request the location URL, if the status of your logic app still is running, it will return 202.
If the status of your logic app is Succeeded, then it will return the results you want.
You can refer this official document.
The definition of the 502 Bad Gateway status code is:
The server, while acting as a gateway or proxy, received an invalid response from the upstream server it accessed in attempting to fulfill the request.
Is it an appropriate status code to respond with if the error was caused by the database? Despite the fact that the definition of the 500 Internal Server Error status code doesn't state that the error has to be internal, I don't like using it when the error is external.
Can the web server be considered to be a gateway or a proxy, since it is performing tasks other than communicating with the database, such as making calls to other APIs and services?
No, I don't think an HTTP 502 Bad Gateway error is appropriate when a database error occurs.
HTTP errors say something about the HTTP protocol. This specific error indicates a server is trying to relay the HTTP request, but the upstream server did not respond correctly.
Your web application communicating with a database server is outside the realm of HTTP and any errors should be wrapped in the generic HTTP 500 Internal server error response code.
There is no reference for the Database error status code. You can use 500 Internal Server Error as a response.
I am trying to develop a client application that calls a RESTful web service. As part of a RESTful design, the service uses a variety of HTTP status codes to communicate state back to the caller. For instance, if I request a resource that doesn't exist, the service responds with a 404 status code. Likewise, if I pass in malformed parameters, the service responds with a 400 (Bad Request) status code. Silverlight 5 automatically converts these into WebExceptions. Is there anyway I can get SL to not throw exceptions but return a legitimate response object with the status code, etc set to the what was received so that I can decide how to handle the response in my code?
(To further clarify, it appears this is only the case for status codes in the 400 and 500 ranges.)
AFAIK, there is no solution to avoid exceptions. Worse than that, it might be hard or even impossible to get the actual HTTP code (I'm not certain there, I haven't tried too hard).
You'll probably want to develop an HTTP request tool that traps WebException and provide an error status to the caller.
My web application uses ajax and i check request is ajax request or not via php codes. If not then i generate 404 error otherwise run php codes that associated ajax function.
If user or search spider tries to reach ajax function page(ex: /books/ajax/books_list) web app return 404 not found status code and i see a lot of 404 errors in google webmaster tools.
I should change 404 status code but which one is right for this condition ? Can be "406 not acceptable" ?
I think 403 (Forbidden) probably best describes it. The resource is there, but you've determined that you're not going to give access to that resource, and even authenticating the user isn't going to help.
I would suggest that you return the 406 you suggested. The only alternatives worth considering are '501 not implemented'
The server does not support the functionality required to fulfill the request.
This is the appropriate response when the server does not recognize the request
method and is not capable of supporting it for any resource
And '403 Forbidden'
The server understood the request, but is refusing to fulfill it.
Authorization will not help and the request SHOULD NOT be repeated.
If the request method was not HEAD and the server wishes to make
public why the request has not been fulfilled, it SHOULD describe
the reason for the refusal in the entity. If the server does not
wish to make this information available to the client, the status
code 404 (Not Found) can be used instead.
Not sure how you determine whether it's a proper Ajax request. If you expect it to be POST, but the spider uses GET, then it should be 405 (Method Not Allowed).
You should not be using 406: it means "not acceptable", in the sense that you cannot support the HTTP Accept: headers that the browser sent. This would likely be incorrect (as you likely aren't checking the Accept headers at all).
If you really reject the request because it comes from an unauthorized client, then 403 is appropriate.
It's my understanding that SE spiders get a little skittish if they see errors that indicate server problems. (A 406 can indicate a badly implemented server.) A 404 doesn't describe what you're looking for, as the resource is there, but a 403 (forbidden) just lets the spider know that this page isn't for them. You can also use your robots.txt file.