Скачать или смотреть How to Change a JSON Pair Value Using jq in Kubernetes

Learn how to change the value of a JSON pair in Kubernetes secrets using `jq`. This guide provides step-by-step instructions on modifying JSON objects easily.
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This video is based on the question https://stackoverflow.com/q/77519335/ asked by the user 'Nathanaël Blanchet' ( https://stackoverflow.com/u/12913765/ ) and on the answer https://stackoverflow.com/a/77519362/ provided by the user 'Bill' ( https://stackoverflow.com/u/3671801/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Introduction

Working with JSON data is a common task in programming and configuration management, especially in environments like Kubernetes. A frequent requirement is modifying specific values within a JSON object. This guide will address a specific problem: changing the value of a JSON key using jq, a powerful tool for processing JSON.

The Problem

Imagine you have the following JSON structure representing a Kubernetes secret:

[[See Video to Reveal this Text or Code Snippet]]

In this JSON, you want to change the last character of the POSTGRES_PASSWORD value from K to =. Additionally, you'll want to ensure that your command can handle variations where the key could be any password. Essentially, you're looking to implement a global rule that modifies any password's last character to =.

The Solution

You can achieve the desired output using an efficient jq command. Here’s how you can do it:

jq Command

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Breakdown of the Command

Let’s dissect this command to understand how it achieves the desired modifications:

with_entries: This function iterates through each key-value pair in the .data object, allowing us to modify it directly.

sub("K$"; "="): This expression uses the sub function to replace the last character K with =. K$ specifies that we’re targeting the last character at the end of the string.

Modification of Labels and Names:

The command then modifies the label POSTGRES_PASSWORD to ANY_PASSWORD.

It also changes the name postgres-password to any-password to follow the same generic naming convention.

Expected Output

By running the command above on the input JSON, you’ll receive the following output:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Using jq to modify JSON data can streamline your workflow in Kubernetes and other environments. The command provided not only replaces the last character of any base64 password but also updates the associated labels and names, making it a practical solution for managing Kubernetes secrets.

By mastering such commands, you can efficiently handle and manipulate JSON data that is critical in various operations, such as configuration and deployment processes. Happy coding!