Month: February 2019

Automated Jenkins CI setup for Go projects

I was helping a friend on a project with some tasks amongst which code quality. I’ve set up some tools (gometalinter first, then golangci-lint) and integrated them with Travis CI.

Then GitHub decided to give free private repositories and my friend made the project private. Travis and other CI systems require paid plans for private repositories so I decided to set up a Jenkins environment. I’ve used Jenkins before, but never configured it myself. I thought it’s going to be a quick click-click install process, but I’ve found myself in front of various plugins, configurations, credentials and all sort of requirements.

One of the first things that come in my mind when I have to do something is if I’ll have to do it again later and if I should automate the process. And that’s how a pet project was born. My purpose was to write a configuration file, install the environment, then configure jobs for the repositories I need.

I’ve created two job templates, one for triggering a build on branch push, one for pull requests (required webhooks are created automatically). Based on the templates, I just wanted to create a new job, insert the GitHub repository url and start using the job.

The job templates are aiming at Go projects to run tests and code quality tools on (all required tools are installed automatically). Other configured actions are automatic backups and cleanups. And you’ll also find some setup scripts for basic server security and requirements.

There are things which could be improved, but now I have a click-click CI system setup called Go Jenkins CI.

 

 

Protect Docker secrets files

I have a Docker container managed with Docker compose, which defines the unless-stopped restart policy. But my container never starts after I reboot the machine. But it does restart if I just restart the Docker service. I have a similar setup on another machine which I have no issues with.

I kept on searching the issue until it hit me all of a sudden. I’m using secrets read from files. The files are in the /tmp  directory which gets cleared, thus the container fails to start.

When I defined the secrets files, I just threw them away from the source code repository, without thinking too much where. I wasn’t even sure if I was going to use them for a long time.

Dev testing

A user story is not done after the code has been written. Also, the developer’s part is not done after the code has been written. I strongly believe in dev testing: after implementing, the developer will once again read each line of the requirements (they had already done this at least once before implementing, right?!?!) and manually test the feature (even if they’ve written automated tests). At least a sanity test to make sure the QA colleagues will not get back to them after a few minutes of testing or every few minutes with another issue.

The interaction with the QA colleagues should be more in breaks. I want to see those people get bored like hell because they just need to check the implementation against the requirements and get back to chatting because everything is OK. If they get back with special situations, corner cases, weird exceptions, everyone’s doing a great job.

We’re human, we forget things while developing, it’s OK. But if the number of things is too big to fit in memory and it increases with every feature, maybe we should read the requirements a few more times and test each one of them. And we should ask questions. The code is done after we understand, implement, test.

And always ask ourselves what happens to the other parts of the app if we do just a small change in the old code. Then test. Yes, we, the developers, must test!

The mid-language crisis

A while after I wrote the Apixu libraries for Go and PHP, they asked me if I could help them with some issue a client had when trying to install the Python library. I quickly tested and sent them steps on how to install all requirements. And I noticed the library could use some additions.

My experience with Python was of a few lines and I felt like it would be a good context to write a few more, to understand the language a little better, to learn about its requirements, ways to set up a library and write some tests to validate JSON schemas. A clean language with a simple package manager and clear error handling. Basic integrations with Flask and Django were pretty smooth.

One thing I like about Apixu is they have multiple libraries and after freshening the Python one I was inspired to do more. And there was where to choose from.

JavaScript is an old friend but we met only in the browser some years ago. It was time to face its server side of the moon and add some touches to the NodeJS library. I’m not a huge fan of callbacks, but Promises are indeed a nice way to handle responses. Express was easy to start with, I like its micro framework feeling. The package manager, npm, doesn’t seem too far from PHP’s composer, we got along well. Continue reading The mid-language crisis

Encrypt column in PostgreSQL

PostgreSQL has a nice encryption (and hashing) module called pgcrypto which is easy to use. Using a provided key, you can quickly encrypt a column which contains sensitive information.

While the setup is fast and the usage is simple, there could be some disadvantages in some contexts:

  • be careful how you send the encryption key to the database server (if public, use SSL for transport, else keep it in a private network at least)
  • data is encrypted/decrypted in the database, so the transport is in plain (watch out for memory dump attacks)
  • some queries are very slow, as the decrypt operation is performed on the entire table if you want to sort or filter by encrypted columns

Continue reading Encrypt column in PostgreSQL