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All posts with the tag "terminal"
I was working on UV Run + PEP 723 Is A Match Made In Heaven and I wanted to grab a screenshot of a TUI, but my terminal is full screen and the TUI was then super stretched… Nice for working and using it, but not nice for a screenshot going into a blog post… see the difference export COLUMNS=120 does here!
COLUMNS=120 mytui.py
mytui.py
Awesome awesome TIL with COLUMNS for some nicer terminal printouts for READMEs and such
I needed to save a website earlier and this was just what I needed…
docker contexts are great, would recommend putting them in your prompt though (via starship or something else)… here’s why
I like to manage my containers remotely - I have a nice development setup on my desktop and I try to keep my server as bare-bones as possible. For a while I’ve been using ansible which makes it easy to manage configuration etc on other machines. But I recently learned about docker contexts and I’m planning to scale down my homelab management to just docker-compose stacks rather than a bunch of super complicated ansible playbooks
So, setting up a context is easy - it’s basically an ssh connection to another machine!
docker context create koober --docker "host=ssh://nic@koober"
koober is one of my dev machines and my ~/.ssh/config is setup such that I can ssh nic@koober, this makes the context work really seamlessly.
So there’s the default context (the machine you’re on) and now I have koober
To use it you run docker context use koober
And then to check we can ls the contexts
docker context ls
NAME DESCRIPTION DOCKER ENDPOINT ERROR
default Current DOCKER_HOST based configuration unix:///var/run/docker.sock
koober * ssh://nic@koober
Notice the * - that indicates that’s our current context.
Now here’s where things get hairy… you’ve gotta be super-aware of what context you’re using. I have an indicator in my starship prompt that shows the current context, but since I’m new to using them I kind of didn’t notice it until I ran into this issue…
I’m working on a python application in docker but was not able to execute the entrypoint even though I KNEW the file was there… let’s take a look
Here’s a minimal hello world applycation in docker to illustrate the issue
# main.py
print("hello world")
# Use an official Python runtime as a parent image
FROM python:3.11-slim
# Set the working directory in the container
WORKDIR /app
# Copy the current directory contents into the container at /app
COPY . /app
# Run the main.py script as the container's main process
CMD ["python", "main.py"]
services:
hello-world:
build: .
volumes:
- .:/app
Notice volume mounting in my project directory . to /app as a common practice to develop inside the container
Here’s where I started to question my sanity…
✗ docker compose up
[+] Running 1/0
✔ Container docker-context-example-hello-world-1 Created 0.0s
Attaching to hello-world-1
hello-world-1 | python: can't open file '/app/main.py': [Errno 2] No such file or directory
hello-world-1 exited with code 2
python can't open file? hmm… Let’s take a look at the image
First let’s make sure we get the image name right
✗ docker container ls -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
3d7285fc39e2 docker-context-example-hello-world "python main.py" 10 minutes ago Exited (2) 44 seconds ago docker-context-example-hello-world-1
Now we can docker run --rm -it --entrypoint /bin/bash --name debug docker-context-example-hello-world
❯ docker run --rm -it --entrypoint /bin/bash --name debug docker-context-example-hello-world
root@ee46d0e22de8:/app# python main.py
Hello, World!
root@ee46d0e22de8:/app#
WHAT THE HECK??
What happened turns out to be pretty simple once we realize I’m using contexts…
koboer is a remote context, the docker run and docker compose up commands are interacting with the docker socket on that machine.
So if I compose up the stack notice that there’s a volume bind mount in there - well those do not work with contexts (or at least I’m not aware of hose to make it work) and so the /app directory was getting blown away essentially with an empty overlay…
But when running with just docker run with no volume mount, the code was copied in during the build and is right where we expect it…
❯ docker run --rm -it --entrypoint /bin/bash --name debug -v .:/app docker-context-example-hello-world
root@903f591c0384:/app# python main.py
python: can't open file '/app/main.py': [Errno 2] No such file or directory
root@903f591c0384:/app#
Adding a `-v .:/app` to match the compose file, we get the same error...
If we switch to the default context we are back up and running as expected
✗ docker context use default
default
Current context is now "default"
nic in /tmp/docker-context-example via v3.13.0 (dev) NO PYTHON ENVIORNMENT SET
❯ docker compose up
[+] Running 1/0
✔ Container docker-context-example-hello-world-1 Created 0.0s
Attaching to hello-world-1
hello-world-1 | Hello, World!
hello-world-1 exited with code 0
nic in /tmp/docker-context-example via v3.13.0 (dev) NO PYTHON ENVIORNMENT SET
❯ docker run --rm -it --entrypoint /bin/bash --name debug -v .:/app docker-context-example-hello-world
root@4045b6aa8883:/app# python main.py
Hello, World!
root@4045b6aa8883:/app#
Successful runs on both accounts with the volume mount
Context is king
I am moving a hefty amount of data to a new ZFS pool due to some corruption and I want to avoid using zfs send/recv for this just to make sure I don’t propagate any corrupted data to my new pool.
I’ve used rsync for simple things before but I needed this to be a little smarter and I wanted to see simple progress without flooding my terminal with a billion filenames.
TLDR:
rsync -aHAX --chmod=Da+s --info=progress2 --inplace --exclude='encrypted/docker/frigate-media' /tank/ /harbor/
-aHAX: Preserves attributes (archive mode, hard links, ACLs, extended attributes). –chmod=Da+s: Ensures the setgid bit is applied to directories. –info=progress2: Provides detailed progress information, including overall data transfer stats. –inplace: Writes directly to the destination file, avoiding temporary files (useful for large files). –exclude=‘encrypted/docker/frigate-media’: Excludes the specified path (relative to the /tank root). /tank/ /harbor/: Ensures the contents of /tank are copied directly into /harbor.
hostnamectl is apparently a linux utility for easily changing your hostname in a variety of ways
❯ hostnamectl --help
hostnamectl [OPTIONS...] COMMAND ...
Query or change system hostname.
Commands:
status Show current hostname settings
hostname [NAME] Get/set system hostname
icon-name [NAME] Get/set icon name for host
chassis [NAME] Get/set chassis type for host
deployment [NAME] Get/set deployment environment for host
location [NAME] Get/set location for host
Options:
-h --help Show this help
--version Show package version
--no-ask-password Do not prompt for password
-H --host=[USER@]HOST Operate on remote host
-M --machine=CONTAINER Operate on local container
--transient Only set transient hostname
--static Only set static hostname
--pretty Only set pretty hostname
--json=pretty|short|off
Generate JSON output
See the hostnamectl(1) man page for details.
I learned there’s transient and static hostnames, so that’s cool…
The thing I needed was hostnamectl --static hostname babyblue-aurora
pretty sweet tool
Plasma shits the bed a little too often on Fedora for me right now but I finally have a quick fix…
sudo killall plasmashell
kstart plasmashell