Quickly format and manipulate JSON in vim using jq

Miha Filej — Tue, 24 Jan 2023 20:45:20 +0000

Ever needed to check whether the JSON you just wrote is valid? Or wanted to quickly rename keys in a JSON array?

There are two components worth understanding that we will later put together.

First, a brief introduction to jq — a wonderful tool for manipulating JSON on the command line — like sed for JSON data as the official website describes it. It is truly powerful and able to manipulate JSON in a myriad of ways. When run with no arguments, it simply formats the given document:



$ echo '{ "foo":   "bar"     }' | jq
{
  "foo": "bar"
}

Second, vim allows you to pipe the contents of the current buffer into a unix command. The command for passing the current buffer through jq would be:



:% !jq

Combining the two, we get a convenient way to format JSON, or really, manipulate the contents of a buffer in any way (another example I use often is sorting through !sort).

How about manipulating JSON? Let's look at two simple examples using the same JSON document. The following command will rename the "size" key to "variant":



:%!jq '.items |= map(.variant = .size | del(.size))'

How about uppercasing every value in an array? Easy enough:



:%!jq '.items |= map(.variant |= ascii_upcase)'

Savvy vim users will recognize that % is in essence just a way to tell vim to use every line in a buffer (see :help :%). We can just as easily use a subset of the buffer, either by specifying the line numbers explicitly or using visual selection (shift-v):

That's it! I hope this technique can streamline your workflow and make you a more efficient vim user.

Bonus: a GPT-generated haiku about vim and the unix pipeline:

Vim sharp as a knife
Unix pipeline, ever wise
Together they thrive

Back up Fly Postgres with GitHub Actions

Miha Filej — Sat, 21 Jan 2023 17:09:16 +0000

Fly Postgres stores its data on volumes, and the fine folks at Fly.io set up automatic snapshots for us. However, I sleep better at night knowing that my databases are backed up with pg_dump.

I found surprisingly few results when I searched for a quick solution to this problem. One of the solutions was a python script, which seemed overkill for such a simple task, but it was a useful starting point. In the end, I came up with a relatively short backup.yml that does the job:

The task will run every day at 4AM. workflow_dispatch is there so that the task can be run manually as well.

Don't forget to set the correct region, update PGUSERand PGDATABASE, as well as replace your-fly-db-app-name, your-s3-bucket, and your-path.

You will also need to visit your repository settings and set the following secrets:

FLY_API_TOKEN — A Fly personal access token (generate one here)
PGPASSWORD — the password for the database being backed up

And finally, don't forget: a backup is not a backup if you've never tried restoring it!

DEV Community: Miha Filej

Quickly format and manipulate JSON in vim using jq

Back up Fly Postgres with GitHub Actions