I'm trying to debug an API issue I have that occurs when my app tries to access a sleeping Heroku Dyno. The problem is it takes a while for a dyno to naturally sleep so it really slows down the debug process.
I know how to turn off a dyno but the bug I'm try to fix seems to happen when the app makes a request to a sleeping dyno that doesn't immediately respond, yet eventually responds.
I got the definitive answer from a Heroku engineer. It's no, you can't force a dyno to sleep.
Related
I have a website hosted on heroku. Whenever I load it for the first time after awhile (I haven't figured out the exact interval yet, be it days or hours), it takes upwards of 15 seconds to load. Subsequent loads are <1second, even if I clear the cache completely and open it in an incognito tab.
Why might this be? It almost seems like some kind of DNS issue but I haven't really got a clue. I don't know how to troubleshoot something like this. The situation seems to be the same even on other computers at other locations.
Quoting the Heroku docs:
If an app has a free web dyno, and that dyno receives no web traffic in a 30-minute period, it will sleep.
When the dyno receives traffic again, it will take a few seconds to wake up, hence the delay you've experienced.
Note that the Heroku free tier also has a maximum number of dyno hours per month. A sleeping dyno doesn't use any hours, but it does when it's active. When the hours are used up, the dyno won't wake up to incoming traffic.
You can see your remaining quota of dyno hours with:
$ heroku ps -a <app name>
Heroku suggests upgrading to a hobby dyno if your app needs to be permanently accessible. More info on https://devcenter.heroku.com/articles/free-dyno-hours
On the free tier, Heroku dynos go to sleep if they aren't used after an hour or something like that. They take a few seconds to wake up. Pay for the service and it stops happening, or write a script to ping your site every couple minutes or something.
I'm testing an app with a worker and a web dyno on Heroku free tier and I'd like to keep the worker alive to be able to execute background tasks while letting the web dyno idle. By default they both go idle in 30 mins even if I have things queued on the worker.
I understand there're ways to keep the web dyno alive (and with that the worker as well), and there're ways to keep the web alive while scaling down the worker. However I'd need the worker alive and the web in idle.
I tried running a recurring job on the worker which would
Restart the dyno.
Scale the dyno down and then back up.
Both approaches worked (as in they restarted and scaled the dyno correctly) but the worker dyno would still idle after 30 mins (as if it's dependent on the web dyno). Edit: yep, that's pretty much the case as explained here: https://devcenter.heroku.com/articles/free-dyno-hours#dyno-sleeping
I could do this form the outside but it seems I'd have to constantly check for the state since a new restart doesn't seem to give me 30 mins headway. I'd also have to expose the API key which I'd like to avoid.
If I've gotten you right, you're trying to stop the web dyno and leave the worker dyno alive.
You could do that by going to the Resources tab:
And then in the 'web' section:
Press the pencil, toggle it off and press 'Confirm'.
As a workaround I currently remove the web dyno and explicitly enable it when I need it. As explained here:
Worker-only Free dynos do not sleep since they do not respond to web
requests.
My workaround was to just create two apps that deploy automatically from the same repository. Then, all you would need to do is enable the worker dyno for one and the web dyno for the other.
I'm creating a chatbot with dialogflow and I have a webhook hosted on heroku (so that I can use python scripts). The webhook works fine most of the time. However when I haven't used it in a while it will always fail on the first use with a request timeout. Has anyone else come across this issue? Is there a way to wake up the webserver before running the script I have written?
Heroku's free dynos will sleep after 30 minutes of inactivity.
Preventing them from sleeping is easy. You need to use any of their paid plans.
See https://www.heroku.com/pricing
Once you use a Hobby dyno, your app will never sleep anymore and you shouldn't be getting request timeouts.
Alternatively, you can also benchmark what's taking a long time to boot your app. With a faster boot time, the first request would be slow but wouldn't get a timeout.
Heroku times out requests after 30 seconds.
I have deployed a Hubot on Heroku to interact with Slack. I am using a free dyno currently. After 30 minutes of inactivity, it goes to sleep. It wakes up when pinged from Slack. However, the first request is lost in the mix. So the user has to type the command a second time. Is there an easy way to make the bot wake up and still handle the first command?
As stated in the documentation :
To get around this, you can use the hubot-heroku-keepalive script, which will keep your free dyno alive for up to 18 hours/day. If you never want Hubot to sleep, you will need to upgrade to Heroku's hobby plan.
I use it so Hubot is at least online from 6 AM to midnight.
I've got a phantomjs app (http://css.benjaminbenben.com) running on heroku - it works well for some time but then I have to run heroku restart because it requests start timing out.
I'm looking for a stop-gap solution (I've gone from around 6 to 4500 daily visitors over the last week), and I was considering exiting the process after it had served a set number of requests to fire a restart.
Will this work? And would this be considered bad practice?
(in case you're interested, the app source is here - https://github.com/benfoxall/wtcss)
It'd work, as long as you don't crash within I think 10 minutes of the last crash. If it's too frequent the process will stay down.
It's not bad practice, but it's not great practice. You should figure out what is causing your server to hang, of course.