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by AdrienPoupa 933 days ago
PHP dev here, we have extensions for development that make no sense in production, xdebug for example. You need it for breakpoints and debugging in general but it should not be installed in production. So we extend our production image and install it on top of it. Similarly, we include Composer (package manager) in the dev image only as we only need the installed dependencies in production but not the package manager. Our dev image is a flavor of the production one, really.
2 comments
comprev 933 days ago
Would multi-stage Docker builds not help here? Composer executes in one step and the result artefacts are copied into a "clean" PHP image without Composer installed.
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twunde 933 days ago
Based on the description they are doing a multi stage build, but using the prod container as a base and then building the dev container atop that. But yes you could easily go the other way with dev building an artifact and adding it to a secure locked down container. This is less typical with dynamic languages that don't typically create a single binary, but still comes up. The downsides are that your prod container is now significantly different and for dynamic languages the fast feedback loop now has a slowish build step
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AdrienPoupa 933 days ago
This what we are doing for the prod container that does not have Composer installed yes.

But in development it's much easier to have it in the image. Additionally we do not bundle the code in the dev image but bind mount it in Docker Compose, which is much faster than rebuilding the image to test changes in development; PHP not being compiled allows us to do that to reduce the feedback loop duration.

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nullify88 933 days ago
In my experience, Xdebug absolutely made sense in production just not enabled by default for all requests. A lot of its functionality can be enabled via a cookie for a single session, and its made debugging production much easier as well as identifying bottlenecks in code or production infrastructure.
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AdrienPoupa 933 days ago
That's certainly possible but we have other tools for that such as NewRelic that served us well.
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