I'm working on a project in the Google Cloud App Engine (node.js flexible runtime) and while I've had a pretty good experience with it thus far, I've recently ran into a problem where the engine will sometimes not respond a specific pubsub notification. Sometimes, the results will appear after a few minutes, but often times it requires me to redeploy the app and lose any messages that I had queued up prior. Interestingly enough, when I send a pubsub message through a different subscription, the engine responds to it well. The backlogged messages are then handled, but sending the problematic message again will still not work.
I'm not really sure how to solve this issue. There is no evidence that google received the message from pubsub in the logs. Additionally, waiting for this long will have negative impacts on the project overall, implying that the messages will reach the end destination given enough time.
I'm willing to provide more information to help reproduce the error.
Thanks in advance
Edit The issue has increased significantly in severity. Please see the updated post I made to see the current extent of the issue.
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I'm planning a project and working through all the potential issues I might face. One that I keep running into which might be specific to my project is concurrency issues. From my understanding, Azure Functions scale when under demand which is exactly what I'm looking for but causes a problem when it comes to concurrency. Let me explain the scenario:
Http triggered Azure Function which does the below
Gets clients available credit, if zero, auto-charge clients card.
Deduct credit from the client for the request.
Processes the request and returns to the client.
Where I see an issue is getting the available credit and auto-charging card. Due to the possibility of having multiple instances of the function I might auto-charge the card multiple times and on top of that getting and deducting the credit will be affected.
I'm wanting the scaling of Azure Functions but can't figure a way around these concurrency issues. Any insight or pointers in the right direction would be very much appreciated.
I've been working on a project utilizing the Gcloud pubsub platform on the node.js flexible runtime and for some reason have had some pretty crazy latency that has been increasing in severity over time. At first, only messages of a certain kind would sometimes experience heavy latency. However, as I've continued working over the past few days, now all messages are experiencing latency reaching over several minutes regardless of type. It's reached the point where testing has become impossible because the latency is taking so long.
What could be done to help alleviate the issue? I have not edited the code receiving the messages except for the function handling the messages. I'm receiving them through the subscription.on() function.
Please let me know what information I can provide to help reproduce the error. Thanks in advance.
Edit: I was able to get it working again by deleting the topic & subscriptions and recreating them. Now latency is at a minimum, but I'm still not sure what caused this issue. Maybe a large backlog of unprocessed messages? Any ideas would help to avoid this in the future.
EDIT: STILL NOT ANSWERED. I appreciate the advice I have received so far, but I still have not found a proper way to test the amount of resources my server is using. I decided to use GCE instead of GAE but I still want to measure the resource usage.
I have searched all over google as well as SA and can't seem to figure this one out.
I would like to deploy my (very small) node.js server to either Google App Engine or Google Compute Engine (not sure which to use yet).
I see that they charge based on how many resources you use, but how can I check this before I make my decision? Basically what I would like to do is find a way to analyse my server and see what CPU/DISK/NETWORK/RAM/Etc it uses, and then possibly make some refinements to my code to get the usage down as low as possible.
I am a hobbyist programmer and this server is just for personal stuff so I don't need anything fancy. I just want to get it hosted on google and not my home server. My real fear is that, since I am not a professional, my code might be doing some crazy background stuff repeatedly that would rack my usage up for nothing.
Quick rundown on what my server does:
Basic node.js express template that IntelliJ made me, then I added my code to sit and listen to a Firebase. When the firebase gets a message (once or twice a day maybe, text message equivalent size) the server sends a quick GCM/FCM message to a few devices. Extremely simple server, very little code. Nothing crazy.
As a little bonus for me, if you have a suggestion as to which platform I should use, I am all-ears.
If you do not need this server to run 24x7, use App Engine. It stops an instance if it is not being used for 15 minutes. The startup time for new instances depends on your code, but for Node.js instances it should not be long.
Generally speaking it is easier to run an app on App Engine than Compute Engine, but if you use a single instance and don't change code often the difference is negligible.
App Engine has a generous free quota. You may end up paying nothing until the usage gets over a certain threshold.
You can run some diagnostic tools on your existing server, but even then you will get an approximation - a server with a different combination of resources sitting on a different network may use resources differently. You may be able to get a rather accurate estimate of memory usage, though.
If this is a small app with not too many users, even a small instance should be able to handle it. There is no harm in trying - start with the smallest instance, test, go to the next instance up if tests fail. Your key concern should be to have enough memory to handle a small number of requests.
As for the number of requests your server can handle, you can configure automatic scaling. It is a default option in App Engine and can be enabled for flexible runtime. Then you can have the smallest instance (i.e. your server does not crash due to the lack of memory) running, and another instance will be added if and when that small instance is not enough.
Well, after over a month I figure I might as well answer this myself.
What I ended up doing was creating a basic instance on Computer Engine (the micro. Smallest one available) and letting it just sit there for a few weeks. I looked back at the data to see what some good baselines were and took note.
Then I took my server code and ran it on the server. I left if there for a few days, changed it, updated it, etc. Just tried to simulate the things I would be doing. Sent messages on my client app (that's what this server is doing after all is said and done) and I let this go on for a few more weeks.
The rest is history. I looked at the baseline then looked at my new memory, CPU, network and disk usage and there we go. Good to go. My free trial still isn't even over so it was a free experiment.
The good news is that my server is more 'lightweight' than I thought.
I figured out that there's always latency of about two to three seconds when sending messages through the Bot Connector of Microsoft's Bot Framework independent of which channel type I'm using.
This means if I call the POST .../messages API method of my Bot directly (so not going through the Bot Connector) I get an answer within several dozens ms. However, if messages are routed through bot connector (e.g. when I use Direct Line communication or Telegram or any other supported channel) it always takes about two to three seconds until I get an answer.
For a possible user this would not be a good user experience so that I'm wondering whether either I'm doing someting wrong (e.g. Bot Connector settings) or whether this is a general problem and will be improved at a later pont of time.
Thanks a lot in advance.
This is a known issue. The BotFramework is still in Preview, so it has yet to be optimized. Expect to see significant performance improvements in the near future.
I have experienced significant variability when using the Instagram Subscription API. For the most part, the API will not post updates to my end-point as specified during the subscribe initiation. My understanding is that the subscription is configured correctly as any of the updates from my personal account are received.
There seem to be reports across the web talking about significant delays. However, it is my experience that accounts that work do so within seconds but in most instances no subscription messages are never received.
There was discussion on the web also regarding queuing of updates sent through to the subscribe API. Which may make a little sense, however a queue would suggest that updates would be received eventually.
I have requested basic permissions, which is sufficient to request public media from each registered account. Yet, there I have a gut feeling that these permissions could be the problem, so I have started the process of requesting public_content.
At this stage there seems to be a number of developers experiencing similar issues, yet no resolutions.
Has anybody been able to resolve this issue?
I'm subscribed to aspect=media object=user and experiencing a similar issue.
For some users, I'm notified 95% of the time. For other users, I've never been notified of a single post.
In this post nithinisreddy mentions that the data is being "sampled". I think this is the reason. Hopefully it improves after the tags/locations subscriptions are deprecated.