Python/DevOps

Pipeline Editor has been introduced in 13.8 version. What can you do with this tool? Normally, when you edit your .gitlab-ci.yml file, you will find that something is wrong with the code only after you push your changes. It would be great to know that there is a typo or something extremely wrong with this config in advance, right? And for this, you can use Pipeline Editor . There are three things you can do with that tool: Validate pipeline configuration Visualise the configuration Lint the configuration Validation is done automatically when you're editing the file. Okay, so how to start? 🤔 Go to CI / CD section and click the Editor link: Validation After that, you should see the Pipeline Editor: Let's break something! Hmm, what's wrong with this code? 🤔 I've received a message that my CI configuration is invalid because chosen stage does not exist. This make sense! I have a build  job and I inherit from hidden job .default , and I had not set a stage in any of th...

Let's say that you have to log in via ssh into an instance, and you work with GitLab, so you want to keep the private key in GitLab somewhere. Is it secure? Let's see! Custom environment variables You can use custom environment variables. Here you can read more about them (Developers cannot change them, only Maintainers and Owners can). There are two types of variables: Variable (the runner creates an environment variable that uses the key for the name and the value for the value) File (the runner creates an environment variable that uses the key for the name. For the value, the runner writes the variable value to a temporary file and uses this path) It seems that we can use File type for our purpose. We can set up it via API or UI . So, let's do that! Go to project's Settings > CI/CD . There will be Variables section (btw, you can specify variables also per group and even for all projects (in admin panel)). Click Add Variable button and add a variable: Key: ...

The problem : you have many scripts (let's say that they are written in python and you just want to run them typing  python your-script.py ) and sometimes you want to run some of them, sometimes only one, etc. There is no pattern. Additionally you want to trigger these scripts via GitLab API. How can you do this? The first idea: let's create a job for each of them! But... then what? You want to run only a small subset of them and each time this subset might be different ☹️. You might add variables, check them and run only these jobs when IF evaluates to true, like: But, I think that you see the problem of this approach. What about creating a common job without any command? It will be your job to provide a command for script section (for example python run-something-and-upload-to-s3.py ). This way we will have only one job in GitLab and during triggering you must provide a command. The code: 8 lines. Woah! We used rules keyword, because we want to spawn only this job w...

Sometimes you want to test your code on different python versions. Using Travis CI it is very easy, but can we do that or something similar in GitLab? Let's see! The problem : there are some tests written in python and we want to test it on different python versions. We can easily use extends keyword, define some common logic in .test  job and then inherit it in other jobs: But... for each new version we have to define a new job. Maybe, we can do better? GitLab has introduced a  parallel keyword. Additionally, there is a  matrix keyword; using this guy you can run a job multiple times in parallel in a single pipeline, but with different variable values for each instance of the job. But, you cannot change image keyword for example 😞. Maybe there is another way? Have you ever heard about dind (Docker-in-Docker)? If not, here is some info about it: Another way to configure GitLab Runner for docker support is to register a runner with the Docker executor and use the...

How do you apply changes in terraform ? In most cases you run terraform plan and then terraform apply  and type yes . This approach works great on your local machine, but how to apply changes (and only the changes you want!) in GitLab job where you do not have access to shell? How to do that, when you cannot approve the output of apply command? You can use terraform apply -auto-approve , but it might be risky... No one likes to destroy something on production without a priori knowledge. So, can we run terraform plan , check the output and then run terraform apply  in another step? We can, but still it might be risky operation. Why? Because plan and apply  are separated operations! They know nothing about each other. So, apply  can change something which was not showed in plan . But... according to Terraform Documentation : The optional -out argument can be used to save the generated plan to a file for later execution with terraform apply, which can be useful...

 We are going to talk about the trigger keyword today. With this feature you can define a downstream pipeline trigger. So, you can trigger a pipeline in any project (you must have access to this project of course). There are two types of downstream pipelines: multi-project pipelines child pipelines  Let's omit child pipelines and have a look at multi-project pipelines. It is very easy to use. You just need to provide a path to the project and that's it. Remember that you only can trigger a pipeline, not a job ! You can also provide more information like environment variables. As always, I am going to provide some examples, so you will understand it better. The first example: you want to trigger a pipeline in another project after the deployment of your service/s. How to do that? Here we want to trigger this pipeline (project my/run-tests ). Let's say that we want to run some tests after each deployment: We need to add the job which will trigger this pipeline in my/run-...