Author Archives: bullgare

DataDog: use events in dashboards

Using events as datasource is pretty straightforward, and described here — https://docs.datadoghq.com/events/. To use it as a graph overlay (for instance, to show app deployments), you can edit your graph, Event Overlays, and add something like below:

tags:tool:morty,dd_env:$env [something like order-history-*]

1	tags:tool:morty,dd_env:$env [something like order-history-*]

Fixing docker does not want to update images

If you run docker pull, and you see an error like failed to register layer: Error processing tar file(exit status 2): fatal error: runtime: out of memory, there could be 2 reasons. Obvious one — not enough disk space for docker. You can fix it with

docker system prune -af
docker volume ls -qf dangling=true

1 2	docker system prune -af docker volume ls -qf dangling=true

WARNING: It will remove your unused resources like …

How to add and increase swap on CentOS

Adding a swap file without reboot If you are having a dedicated server somewhere with not that much memory, you could decide to add a swap without rebooting your server. To do so, you need to follow the routine:

sudo dd if=/dev/zero of=/swapfile count=1024 bs=1MiB
sudo mkswap /swapfile
sudo chmod 0600 /swapfile
sudo swapon /swapfile

sudo dd if=/dev/zero of=/swapfile count=1024 bs=1MiB

sudo mkswap /swapfile

sudo chmod 0600 /swapfile

sudo swapon /swapfile

Increasing a swap size If something goes wrong with your system, and you see that …

CREATE TABLE IF NOT EXISTS my_tmp_copy LIKE my;

INSERT INTO my_tmp_copy
SELECT * FROM my;

UPDATE my_tmp_copy SET order_count = 5 WHERE customer_id > 0;

RENAME TABLE my TO my_old, my_tmp_copy TO my;

CREATE TABLE IF NOT EXISTS my_tmp_copy LIKE my;

INSERT INTO my_tmp_copy

SELECT * FROM my;

UPDATE my_tmp_copy SET order_count = 5 WHERE customer_id > 0;

RENAME TABLE my TO my_old, my_tmp_copy TO my;

Mock sql (sqlx) db on golang

I am using this library — https://pkg.go.dev/github.com/data-dog/go-sqlmock. That’s how you can use it for mocking db querying:

Backup your Spotify playlists and activity

* http://www.spotmybackup.com/ Simple tool to export all your data into a file. Also you can import it into your account. So it could be used to backup your Spotify data (uses json format, only track ids, no titles). * https://www.tunemymusic.com/ It allows to transfer data between different music services and also export to a csv …

Outline — simple and powerful vpn on your server

https://getoutline.org/ Just a couple of mouse clicks, and it will create a new droplet on DigitalOcean for you (or any other provider from the list). Very easy to install, and works good so far.

Fast and simple mock server app by swagger file

I’ve tried Mockoon for mocking by swagger/OpenAPI spec file, and it works pretty good. It autogenerates the response based on swagger format, and you are able to update any response field the way you want, save your changes and run the mock server with one click on the port you specify. It is a separate …

How to install multiple versions of go on mac m1

For instance, I want to try a new beta, go1.18beta2 (I check if it’s available on the download page). And I already have a regular go1.17, that I want to use as a default one. To do so, I need to do this:

go install golang.org/dl/go1.18beta2@latest
go1.18beta2 download

1 2	go install golang.org/dl/go1.18beta2@latest go1.18beta2 download

Then I can check if it’s okay — go1.18beta2 version #go …

Types of load tests

Load test types explained by k6. Smoke tests Verify that your system can handle minimal load, without any problems. Like 1 rps for 1 minute. Load tests Assess system performance in terms of concurrent users or requests per second. If you want to make sure that you can handle 500 rps, you can gradually increase …