vim encoding/decoding base64 in Kubernetes secrets

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Kubernetes provides the ability to edit secrets from the command line, but there’s a catch: they’re encoded with base64 and kubectl provides no way to encode/decode it.

There are several solutions online to this problem, often involving installing another tool. However, vim can do this with the help of the base64 binary commonly found on Linux systems.

The following solution is based on this StackOverflow post, but with a critical modification to fix unintended behavior.

echo decode in Command Mode

These commands rely on using Visual selection mode to select a block of text that should be encoded or decoded.

This first configuration entry, which can be added in ~/.vimrc, only decodes the selected text in Visual mode and prints it into the Command Mode line at the bottom of the vim editor:

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vnoremap <leader>64 y:echo system('base64 --wrap=0 --decode', @")<cr>

After making a visual selection, type \ quickly followed by 64 to print the base64 decoded line. The ‘quickly’ is because \, known as the ‘leader’, is a special character used to prefix these kinds of custom mappings and has a timeout of 1 second.

This can be extended by setting the timeoutlen variable in vim, but be sure to utilize the ttimeoutlen variable so pressing ESC does not also use the same delay. This post dives into this further.

The --wrap=0 is very important because by default, base64 wraps to 76 characters - that flag will disable this behavior.

decode inline

This configuration line does the same as above, but actually modifies the text inline in the vim editor:

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vnoremap <leader>d64 c<c-r>=system('base64 --wrap=0 --decode', @")<cr><esc>

Use this by typing \ followed by d64 (decode 64).

encode inline

After making modifications to a secret, it should be re-encoded. This following configuration entry allows for re-encoding a block of visually selected text inline in the vim editor:

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vnoremap <leader>e64 c<c-r>=system('base64 --wrap=0', @")<cr><esc>

Use this by typing \ followed by e64 (encode 64)

correctly selecting text in Visual Mode

It might make sense to start Visual selection mode and select an entire line of text to the end with v$. However, this would be a mistake since it also selects the newline character \n.

Instead, to select to the end without the newline, type: vg_

Alternatively if the cursor is already at the end of the line, the reverse selection up to (but not including) the first space character can be done with v + SHIFT t + SPACE (vT ).

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