init

LICENSE

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+MIT License
+
+Copyright (c) 2022 Pouriya Jamshidi
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# Queue Watcher
+
+`qwatcher` is designed to help monitor TCP connections and diagnose **buffer** and connectivity issues on Linux machines related to `input` and `output` queues.
+
+## Why
+
+The idea of writing this program came to me after reading a few blog posts discussing how they faced odd connectivity issues and how it ended up being related to the send and receive queues.
+
+Had they had this tool, they would have been able to find the root cause much faster.
+
+## How
+
+1. Download and unzip the archive file from this URL:
+
+   ```bash
+   wget https://github.com/pouriyajamshidi/qwatcher/releases/latest/download/qwatcher.zip
+   unzip qwatcher.zip
+   ```
+
+2. Make it executable and if you prefer, move it to your `$PATH`:
+
+   ```bash
+   chmod +x qwatcher
+   sudo cp qwatcher /usr/local/bin
+   ```
+
+3. Run it. There are two modes to run `qwatcher`.
+
+   1. Log mode (default): Logs the output to `/var/log/qwatcher.log`
+   2. Monitor mode: Prints the output to the console with `--show_only` option
+
+Let's explore both modes:
+
+1. check every **5 seconds** and **log** connections that surpass **100 kilobytes** in **send** or **receive** queues in `/var/log/qwatcher.log`:
+
+   ```bash
+   qwatcher --recv_q=100000 --send_q=100000 --refresh=5
+   ```
+
+   Then you can use tail to check the file contents:
+
+   ```bash
+   tail -f /var/log/qwatcher.log
+   ```
+
+2. If you want the output to be shown on the **console** and not log to file, use the `--show_only` option:
+
+   ```bash
+   qwatcher --recv_q=100000 --send_q=100000 --show_only
+   ```
+
+   > The default refresh interval is 10 seconds.
+
+The sample output can be seen [here](#what)
+
+Additionally, you can use the [accompanying systemd](qwatcher.service) service to run `qwatcher` in the background and not worry about system restarts:
+
+```bash
+sudo cp qwatcher.service /etc/systemd/system/qwatcher.service
+sudo systemctl enable qwatcher.service
+sudo systemctl start qwatcher.service
+```
+
+### Available flags
+
+```console
+  -h, --help       : show help
+  --recv_q,        : Minimum receive-Q to trigger alert in bytes (default: 10000)
+  --send_q,        : Minimum send-Q to trigger alert in bytes (default: 10000)
+  --refresh,       : Refresh interval in seconds (default: 10)
+  --show_only,     : Show only the current state without logging to file
+  -v, --version,   : Show version
+```
+
+## What
+
+Below output depicts the provided information for a connection:
+
+```console
+======================================================================
+Time:           2022-08-07 - 13:24:27
+State:          ESTAB
+Receive-Q:      0
+Send-Q:         93239
+Local Address:  145.55.162.71:443
+Remote Address: 1.214.249.20:15637
+Process:        timer:(on,740ms,0)
+
+Info:   skmem:(r0,rb425984,t0,tb425984,f6601,w136759,o0,bl0,d3) ts sack bbr wscale:8,2 rto:788 rtt:366.822/52.165 ato:40 mss:1378 pmtu:1500 rcvmss:1332 advmss:1448 cwnd:169 bytes_sent:6134751 bytes_retrans:2575 bytes_acked:6038937 bytes_received:62369 segs_out:4584 segs_in:2850 data_segs_out:4491 data_segs_in:180 bbr:(bw:5.1Mbps,mrtt:117.134,pacing_gain:2.88672,cwnd_gain:2.88672) send 5.1Mbps lastsnd:4 lastrcv:92 lastack:4 pacing_rate 14.6Mbps delivery_rate 5.1Mbps delivered:4424 app_limited busy:33848ms sndbuf_limited:244ms(0.7%) unacked:68 retrans:0/2 dsack_dups:2 reordering:33 reord_seen:720 rcv_rtt:145 rcv_space:14600 rcv_ssthresh:64076 minrtt:112.477
+
+======================================================================
+```
+
+Apart from the send and receive queues, there are additional information that can be useful to diagnose connectivity issues such as `congestion window`, `mss`, `retransmits` and more.
+
+## Tested on
+
+Ubuntu server 22.04.
+
+## Sponsor me
+
+[!["Buy Me A Coffee"](https://www.buymeacoffee.com/assets/img/custom_images/orange_img.png)](https://www.buymeacoffee.com/pouriyajamshidi)  
+[![sponsor](https://img.shields.io/static/v1?label=Sponsor&message=%E2%9D%A4&logo=GitHub&color=%23fe8e86)](https://github.com/sponsors/pouriyajamshidi)
+
+## Contact me
+
+[![LinkedIn](https://img.shields.io/badge/LinkedIn-0077B5?style=for-the-badge&logo=linkedin&logoColor=white)](https://www.linkedin.com/in/pouriya-jamshidi/)
+
+## License
+
+[![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)

qwatcher.nimble

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+# Package
+
+version       = "0.1.0"
+author        = "Pouriya Jamshidi"
+description   = "Linux Queue Watcher"
+license       = "MIT"
+srcDir        = "src"
+bin           = @["qwatcher"]
+
+
+# Dependencies
+
+requires "nim >= 1.6.6"

qwatcher.service

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+[Unit]
+Description=Queue Watcher Tool
+After=Network.target
+
+[Service]
+Type=simple
+RemainAfterExit=yes
+ExecStart=/usr/local/bin/qwatcher --recv_q=100000 --send_q=100000
+Restart=on-failure
+RestartSec=5
+
+[Install]
+WantedBy=multi-user.target
+