Hey there! I was able to setup the Prefect Local UI just fine on an EC2... However, when I register the flow, it does not show up in the UI and "Upcoming Runs" gets stuck loading... I was wondering if anyone else is experiencing this? It seems like the flow UUID gets picked up just fine on the backend local server and when I

flow.register

but nothing seems to be showing up

Hi @Mitchell Bregman could you describe more what you’re seeing? Questions I have: - what happens when you call

flow.register

and what URL is printed? - have you run

prefect backend server

to ensure your are pointed to your local server vs. Cloud?

Hi Chris! Yes, I ran

prefect backend server

before setting up the prefect local server (i.e.

prefect start server

).. When I call

flow.register

, this is the result:

$ python <http://flow.py|flow.py> 
Result Handler check: OK
Flow: <http://localhost:8080/flow/9a703825-7ade-4d92-afc9-d3f8019bf933>

To note: I exposed port

8080

on AWS so that I can access the URL. On the backend, after running the flow registration, I end up seeing nothing being scheduled, i.e.

scheduler_1  | [2020-04-10 22:49:59,153] INFO - prefect-server.Scheduler | Scheduled 0 flow runs.
scheduler_1  | [2020-04-10 22:49:59,254] DEBUG - prefect-server.Scheduler | Sleeping for 300.0 seconds...

Hmmm interesting - could you run:

from prefect import Client; c = Client()

print(c.api_server)

print(c.graphql("query{flow{name}}")

Yup:

Python 3.7.7 (default, Mar 26 2020, 15:48:22) 
[GCC 7.3.0] :: Anaconda, Inc. on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from prefect import Client; c = Client()
>>> 
>>> print(c.api_server)
<http://localhost:4200/graphql/alpha>
>>> print(c.graphql("query{flow{name}}"))
{'data': {'flow': [{'name': 'ETL'}, {'name': 'ETL'}]}, 'extensions': {'tracing': {'version': 1, 'startTime': '2020-04-10T22:55:38.693Z', 'endTime': '2020-04-10T22:55:38.700Z', 'duration': 6503370, 'execution': {'resolvers': [{'path': ['flow'], 'parentType': 'Query', 'fieldName': 'flow', 'returnType': '[flow!]!', 'startOffset': 145955, 'duration': 6268650}, {'path': ['flow', 0, 'name'], 'parentType': 'flow', 'fieldName': 'name', 'returnType': 'String!', 'startOffset': 6435474, 'duration': 27895}, {'path': ['flow', 1, 'name'], 'parentType': 'flow', 'fieldName': 'name', 'returnType': 'String!', 'startOffset': 6477149, 'duration': 12499}]}}}}
>>>

That all seems correct; and your Flow has a schedule attached to it?

For this example, I'm using the ETL example thats in the video above.. no schedule attached to this flow.. but before trying the example ETL flow, I built my own that had a schedule attached - same result

so when you navigate to the Flows tab, it’s just empty?

yup -

you mentioned running on an EC2 instance and port-forwarding; this might be a dumb question but are you sure you don’t accidentally have two server instances spun up? One on your local machine and one on the EC2?

i never set up on server locally.. i set up the server on EC2 in one

tmux

screen and am running the flow in another

I assume refreshing that screen doesn’t help? if you navigate to the interactive API and run the same query:

query{
   flow{ name }
}

does anything show up?

the result from that query:

{
  "graphQLErrors": [],
  "networkError": {},
  "message": "Network error: Failed to fetch"
}

ahhhh ok ok now we’re getting somewhere

hmmm. sorry if this is dumb but i assume

name

gets substituted with

ETL

? regardless, same result in that query

yea it should return the same thing as the python client returned

right.. i wonder where the disconnect is

and you ran

prefect server start

with no configuration?

i tried setting up the server from source as well, same issue

OOO wow I’m sorry I should’ve caught this earlier

alrighty, will test that out in 1 second

of course! anytime

ok, so i set up the port forwarding wiht same rules as

8080

-- do i need to run anything before restarted the server?

i don’t think so

alrighty - still the same 😕 same with the interactive API call

should just be 4200 and 8080 🧐

hmmm... i can set up port forwarding for anywhere so that you can check it out as well, but not sure if thats helpful lol

Hi @Mitchell Bregman — I believe the issue is that the UI is always going to make queries to

localhost:4200

on the machine it’s running on, so I believe that is the root cause. @nicholas might have some more insight here though and can confirm / deny my theory

@Chris White @Mitchell Bregman that's correct - I think the simplest way to get around that would be to modify your

/etc/hosts

file to direct

localhost:4200

traffic to your EC2

Hrm…I’m dealing with something similar (just deployed prefect server in an ECS cluster). @nicholas

/etc/hosts

it’s for name resolution only AFAIK — I’m using

socat

for redirecting localhost traffic to my ECS service

You're right @Manuel Aristarán - it seems like the

/etc/hosts

hack isn't a great solution - working on a PR that will address this!

Hi folks! I'm new to this community and working on evaluating Prefect as our new tool for job automation. I set up the server on a vm and encountered exactly the same issue as @Mitchell Bregman when I tried to access the web UI from my machine via an ssh tunnel. I can work around it with the additional tunnel to port 4200 on the server, but I'd love to see a better solution. Can you all give me any info about the status of the PR mentioned by @nicholas above?

Hi @Mary Clair Thompson and welcome! The PR has been merged to master, I believe it’s slated for release this week (@Chris White can confirm)

Yup, it should be released tomorrow with 0.10.3, along with a blog post (by @nicholas) on how to set things up

@Chris White wonderful, thank you!

@nicholas Thank you so much for all your help and hard work resolving this. This article is fantastic: https://medium.com/the-prefect-blog/prefect-server-101-deploying-to-google-cloud-platform-47354b16afe2 .. PS - Thank you to the whole Prefect team!! You guys are amazing 🙌

I have same problem here - did you find a way to solve it ?

@Adrien Boutreau would you mind asking this in a new thread in #prefect-community so we don't spam everyone in this thread?

👍