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https://github.com/st3v3nmw/pocketses
Learning about Snaps & Snapcraft
https://github.com/st3v3nmw/pocketses
metrics pub-sub publisher-subscriber pubsub python snap snapcraft snapd
Last synced: 24 days ago
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Learning about Snaps & Snapcraft
- Host: GitHub
- URL: https://github.com/st3v3nmw/pocketses
- Owner: st3v3nmw
- License: mit
- Created: 2024-01-03T05:44:11.000Z (12 months ago)
- Default Branch: main
- Last Pushed: 2024-01-05T09:38:14.000Z (12 months ago)
- Last Synced: 2024-10-15T07:31:58.212Z (2 months ago)
- Topics: metrics, pub-sub, publisher-subscriber, pubsub, python, snap, snapcraft, snapd
- Language: Python
- Homepage:
- Size: 173 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
Pocketses
What has it got in its pocketses, precious?!
This is a project I'm using to learn snaps, Snapcraft, Ubuntu Core, & landscape. It runs the following "services":
- A collector to pull CPU, memory, and network statistics from the host, and
- A publisher to push the metrics to all subscribed clients
Areas covered:
- [x] Python snap plugin
- [x] Interfaces
- [x] Pub/Sub with the [Twisted](https://twisted.org/) framework
- [x] Remote builds
- [x] Snap configuration
- [x] Hooks
- [x] Snapd REST API
- [x] Model assertions
### Etymology
What's with the project's name I hear you ask? Well, I've been reading Tolkien's legendarium and naming things is hard _(sobs)_, as someone famously quipped. There's an open challenge to come up with a better name. And if it loses, what then? Well, if it loses, precious, then we eats it whole 🙂.
_Moving on swiftly..._
## Installation
### Source
A few pre-reqs, make sure the following are installed:
- [Snapcraft](https://snapcraft.io/docs/snapcraft-overview)
- [yq](https://github.com/mikefarah/yq)
Then run `git clone [email protected]:st3v3nmw/pocketses.git` to clone this repository and run `make build && make install`.
### Snap store
The version on the snap store is far behind (I disabled the automatic GitHub + Launchpad builds since we're using the super privileged `snapd-control` interface and you'll get rejections from the snap store). We're using the `snapd-control` interface to get pocketses' snap configuration.
If you'd still like to take the path less traveled by, run `sudo snap install pocketses --channel=candidate`.
## Setup
Connect the snap to the `system-observe`, `network-observe` & `snapd-control` interfaces (`sudo snap connect pocketses:`)
## Usage
As mentioned before, this snap has to be run as root since we need to connect to the `/run/snapd.socket` socket through the `snapd-control` interface. Yes, we should probably switch to the snapctl tool but parsing the output seems unwieldy (plus HTTP/JSON is convenient).
```console
$ sudo pocketses --help
usage: pocketses-cli [-h] [--port PORT] [--interval INTERVAL]
options:
-h, --help show this help message and exit
--port PORT Port to run server
--interval INTERVAL Interval in seconds to collect metrics
```
On one terminal, start pocketses:
```console
$ sudo pocketses
Starting publisher...
Collecting and sending stats...
Collecting and sending stats...
```
On two separate terminals, subscribe with two clients:
```console
$ telnet localhost 8888
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
{"cpu": {"count": 8, "utilization": {"overall": 34.3, "per_cpu": [27.6, 51.0, 46.9, 27.8, 28.7, 36.1, 26.3, 29.7]}, "frequency": {"current": 800.0, "max": 4800.0, "min": 400.0}}, "memory": {"virtual": {"total": "15.4G", "used": "42.3%", "available": "8.9G"}, "swap": {"total": "8.0G", "used": "2.9%", "available": "7.8G"}}, "network": {"traffic": {"sent": "1.4G", "recv": "1.9G"}, "addresses": {"lo": ["127.0.0.1"], "wlp108s0": ["192.168.0.104"], "docker0": ["172.17.0.1"], "lxdbr0": ["10.131.100.1"]}}}
{"cpu": {"count": 8, "utilization": {"overall": 14.6, "per_cpu": [14.0, 7.0, 15.8, 9.4, 12.1, 11.2, 19.2, 28.0]}, "frequency": {"current": 500.0, "max": 4800.0, "min": 400.0}}, "memory": {"virtual": {"total": "15.4G", "used": "42.1%", "available": "8.9G"}, "swap": {"total": "8.0G", "used": "2.9%", "available": "7.8G"}}, "network": {"traffic": {"sent": "1.4G", "recv": "1.9G"}, "addresses": {"lo": ["127.0.0.1"], "wlp108s0": ["192.168.0.104"], "docker0": ["172.17.0.1"], "lxdbr0": ["10.131.100.1"]}}}
```
You should see some output after the interval elapses (default interval = 60 seconds).
## Bugs/Features
1. Subscribed clients can "publish" and this output is echoed back too all clients (sender included lol)
## Upgrading Ubuntu Core
- Get the model assertion: `snap known --remote model series=16 brand-id=canonical model=ubuntu-core-22-amd64 > uc22.model`
- Start the upgrade: `sudo snap remodel uc22.model`
- Use `snap changes` & `snap change ` to monitor the process
Count your lucky stars if it passes. Mine didn't:
```console
$ snap change 29
Status Spawn Ready Summary
Done today at 09:04 UTC today at 09:11 UTC Request new device serial
Done today at 09:04 UTC today at 09:11 UTC Prepare remodeling
Done today at 09:04 UTC today at 09:11 UTC Ensure prerequisites for "pc-kernel" are available
Undone today at 09:04 UTC today at 09:11 UTC Download snap "pc-kernel" (1540) from channel "22/stable"
Done today at 09:04 UTC today at 09:11 UTC Fetch and check assertions for snap "pc-kernel" (1540)
[...]
Mount snap "pc" (146)
2024-01-05T09:09:54Z ERROR cannot remodel to an incompatible gadget: incompatible layout change: incompatible structure #4 ("ubuntu-save") change: new valid structure size range [33554432, 33554432] is not compatible with current ([16777216, 16777216])
```
## Resources
- [Create your first snap](https://ubuntu.com/tutorials/create-your-first-snap)
- [Adding Snapcraft parts](https://snapcraft.io/docs/adding-parts)
- [Snap confinement](https://snapcraft.io/docs/snap-confinement)
- [Snap commands and aliases](https://snapcraft.io/docs/commands-and-aliases)
- [The Python snap plugin](https://snapcraft.io/docs/python-plugin)
- [Python command line scripts](https://python-packaging.readthedocs.io/en/latest/command-line-scripts.html)
- [Snap interface management](https://snapcraft.io/docs/interface-management)
- [Build snaps from GitHub](https://snapcraft.io/docs/build-from-github)
- [Snapcraft hook support](https://snapcraft.io/docs/snapcraft-hook-support)
- [Adding snap configuration](https://snapcraft.io/docs/adding-snap-configuration)
- [Supported snap hooks](https://snapcraft.io/docs/supported-snap-hooks)
- [Snapd REST API](https://snapcraft.io/docs/snapd-api)
- [Snapcraft.yaml reference](https://snapcraft.io/docs/snapcraft-yaml-reference)
- [Using the snapctl tool](https://snapcraft.io/docs/using-snapctl)
- [Install Ubuntu Core on KVM](https://ubuntu.com/download/kvm)
- [Upgrade Ubuntu Core](https://ubuntu.com/core/docs/upgrade)
- [Assertions](https://ubuntu.com/core/docs/reference/assertions)
- [Model assertion](https://ubuntu.com/core/docs/reference/assertions/model)
- [Sign a model assertion](https://ubuntu.com/core/docs/sign-model-assertion)