Elixir Terminal output on Fly.io

Phoenix
,
1

I apologize for a tremendously basic question…

I have an Elixir Phoenix back end app that is serving to an electron app. On my local system, everything is working… deployed in pseudo production, I’m having a few issues. When run locally, I have running terminal output that lets me see incoming requests, and key errors.

When I SSH in, the app is running as a service in the background… which obviously does not show terminal output.

Is there a way to get the same information in Fly? The live logs seem to be the machine state, rather than software application state.

3

Hi… No worries! There is no minimum bar for question complexity on the Fly forum, :sweat_smile:…

What do you see in the way of :logger settings in config/dev.exs versus config/prod.exs ?

5

Thanks!

In config.exs

config :logger, :console,
  format: "$time $metadata[$level] $message\n",
  metadata: [:request_id]

In dev.exs

config :logger, :console, format: "[$level] $message\n"

In prod.exs

config :logger, level: :info
6

I believe you can just change that last one to level: :debug and then re-deploy.

(Typically, production logging is less verbose than development, otherwise most people would find the useful parts drowned out by prosaic “Got another request and sent another 200 OK” repetitions…)

7

Unfortunately, not working. The only logs that register are when I spin up a new image.

8

I’d suggest posting those logs—the ones that you do have. Otherwise, we forum readers are short on context.

After boot, there would generally be Preparing to run `/app/bin/server`, the address that Cowboy is binding to, …

9

I think I got the logs to show, but multi-line output is quite… annoying…

If I print an object, then the each line of the object gets a new timestamp and row, and it’s not formatted like it would be on a terminal. Is there anyway to adjust this setting?

10

Glad to hear there was progress…

I may be misunderstanding what you’re trying, but the logging system is principally for gruff, rather isolated, one-liner notifications. (“New SSH login from user mayailurus@example.com.”) It isn’t really intended to visually reproduce 2D output—not when it comes to minutiae like column alignment and VT-100 effects.

Maybe it would be easier† to change your CMD (or similar) to…

bash -c 'set -o pipefail && /app/bin/server | tee /tmp/raw-stdout.log'

(Might need tweaking for local conditions, :open_umbrella:.)

Then tail -F /tmp/raw-stdout.log from an SSH session.

†This is a middle ground in that it will generally miss the fancy escape codes for colors and the like—but should preserve other formatting.

11

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