61 lines
2 KiB
Markdown
61 lines
2 KiB
Markdown
---
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title: Easy feature flags
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date: 2024-12-22
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permalink: daily/2024/12/22/feature-flags
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tags:
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- software-development
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- drupal
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- php
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- sculpin
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cta: ~
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snippet: |
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Have you tried feature flags (aka feature toggles)? This is how I used a feature flag when swapping my podcast player.
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---
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I recently [switched to self hosting][0] the MP3 files for the episodes of the Beyond Blocks podcast.
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The first step was to upload the files, followed by [updating the player][1] on the episode pages to use the HTML audio element.
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As I didn't want the player to switch immediately, I wrapped the new code in a feature flag (or feature toggle) to keep the original player active.
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Later, I could swap the player by enabling the feature flag.
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## How I did it
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Feature flagging is a straight forward concept.
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You isolate the code you want to be togglable within a conditional - i.e. an `if` statement - that you can easily change in the future.
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My website built with Sculpin, so I can add `self_host_podcast_episodes: false` to my sculpin_site.yml file.
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This will be available as `site.self_host_podcast_episodes` and I can use this in my code to show the appropriate player.
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Something like:
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```twig
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{%- verbatim -%}
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{% if site.self_host_podcast_episodes %}
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Show the new player.
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{% else %}
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Show the old player.
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{% endif %}
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{%- endverbatim -%}
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```
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## Here's the thing
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I like feature flags as you can separate deploying a feature from releasing it.
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The code can be deployed but not active until the feature is enabled.
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It's easy to enable, and easy to revert if needed.
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In Drupal applications, I use the [Feature Toggle module][2], so I can toggle feature flags by logging in and updating a checkbox.
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I also [wrote a module][3] with a Twig function so I can check if a feature toggle is enabled directly in a Twig template - the same as I'm doing in Sculpin.
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[0]: {{site.url}}/daily/2024/12/18/self-hosting-podcast
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[1]: {{site.url}}/daily/2024/12/19/working-iteratively
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[2]: https://www.drupal.org/project/feature_toggle
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[3]: https://www.drupal.org/project/feature_toggle_twig
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