https://github.com/balena-io-examples/balena-multistage-dockerfile-example
How to leverage _multi-stage Dockerfile_ with _docker-compose.dev.yml_ to improve DX with balena.
https://github.com/balena-io-examples/balena-multistage-dockerfile-example
Last synced: 3 months ago
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How to leverage _multi-stage Dockerfile_ with _docker-compose.dev.yml_ to improve DX with balena.
- Host: GitHub
- URL: https://github.com/balena-io-examples/balena-multistage-dockerfile-example
- Owner: balena-io-examples
- Created: 2023-11-02T13:45:08.000Z (over 1 year ago)
- Default Branch: master
- Last Pushed: 2023-11-02T13:48:58.000Z (over 1 year ago)
- Last Synced: 2025-01-28T21:35:44.967Z (5 months ago)
- Size: 1000 Bytes
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
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Metadata Files:
- Readme: README.md
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README
# Multi-stage Dockerfile dev setup
This is an example on how to leverage _multi-stage Dockerfile_ with _docker-compose.dev.yml_ to improve DX with balena.
## Principles
- The dockerfile is split in 3 main stages :
- `build` (all the preparation steps, including the compilations steps, etc.)
- `prod` (imports the important files from build and leave out the scaffolding. Then adds the configurations and commands for production)
- `dev` (imports all things needed for test and dev from the build stage. Then adds the configurations and commands for development)
- It's important for `dev` to be the latest step as we'll want to be able to use balena's `live-reload` when pushing in `local mode` and it only works if we run the full Dockerfile (all steps).
- If we were to add a `test` stage it should go between `prod` and `dev`.
- To build a certain stage we use `balena build --target _step_ -t _imagename:tag_ .` ( i.e. `balena build --target prod -t hello:world .` )
- We set the target in the `docker-compose.yml` with `target: prod`
- Then we set the `docker-compose.dev.yml` with `target: dev` so it's overwritten when using `local mode` push.
i.e. :
```
services:
hello:
build:
context: .
target: dev
```
## Limitations
- For live update to work in `local mode`, the `dev` step must be the latest step
- `docker-compose.dev.yml` won't be merged when doing a `build` (currently only works when pushing in local mode). See [this PR](https://github.com/balena-io/balena-cli/pull/2177) for information about how it actually works.