jesugmz

Deploy Next.js static to GitLab pages

Create a basic GitLab CI config:

$ cat .gitlab-ci.yml
image: node

before_script:
 - npm install

jesugmz

Configure SSH with multiple git accounts

Scenario: same git provider, for this example GitHub (this trick is provider agnostic, has been tested with GitLab as well), and we want to have SSH configured for two different users (or more): jesugmz and myseconduser.

Step 1

Configure SSH config in order to get an alias with different configuration as follow:

$ cat ~/.ssh/config

jesugmz

Count all the lines of given directories recursively

In this example want to count the number of lines of every PHP file in two directories, dir-1 and dir-2/subdir:

find {dir-1,dir-2/subdir} -name '*.php' | xargs wc -l

The output is the sumarize of each line:

jesugmz

Git tag regex validation using Makefile

This is a portion of a Makefile where I select a Git tag, validate its name using regular expresion and build a Docker image with it as tag.

# it is evaluated when is used (recursively expanded variable)
# https://ftp.gnu.org/old-gnu/Manuals/make-3.79.1/html_chapter/make_6.html#SEC59
git_tag = $(shell git describe --abbrev=0 --tags)
# Semantic versioning format https://semver.org/
tag_regex := ^v([0-9]{1,}\.){2}[0-9]{1,}$

jesugmz

Check if there is shell command output

Consider the following scenario:

Problem The execution of a shell command (Radon in this example) does not retrieve an status code different to 0 when there is output (if there is output there are issues). The command does not gives parameter to handle it.

Simple solution

Check if the length of the output is non empty (-n).

jesugmz

Docker Hub automated builds with multi-stages

Docker Hub automated builds are nice to build automatically Docker images when code is pushed to the linked git repository but they do not support Docker multi-stages by default.

To do so is needed to override the default commands that Docker Hub uses internally by using hooks.

In this example we have two stages:

• dev will be built from master branch only
• prod will be built per git tag

jesugmz

Just add the following flag: pytest -W ignore::DeprecationWarning

More info

jesugmz

Check Docker Swarm labels of a specific Docker Swarm node:

docker node inspect --format '{{ .Spec.Labels }}' node-general-2

In this example we want to see the labels of the node named node-general-2.

• https://docs.docker.com/config/labels-custom-metadata/#manage-labels-on-objects

jesugmz

CoreOS notes

• fleet has been deprecated https://coreos.com/blog/migrating-from-fleet-to-kubernetes.html

• Cloud init has been deprecated https://coreos.com/os/docs/latest/provisioning.html#using-container-linux-configs

• Default time zone is UTC, recommended to avoid confusion between different zones https://coreos.com/os/docs/latest/configuring-date-and-timezone.html

• Container Linux Config specification https://coreos.com/os/docs/latest/configuration.html

jesugmz

Let’s Encrypt certificate for dockerized Nginx under Cloudflare

Real example about how to generate and add a Let's Encrypt SSL/TLS certificates to a dockerized Nginx under a running Docker Swarm using Cloudflare DNS to enable HTTPS.

https://certbot.eff.org/docs/using.html#dns-plugins

https://certbot-dns-cloudflare.readthedocs.io/en/stable/

1. Generate the certificate