---
tags:
  - docker
---

The `entrypoint` key in a Docker compose file is useful for running any advanced
scripts before the the main `cmd` is executed.

```sh
app:
 image: python:3.11-slim
 entrypoint: ["./entrypoint.sh"]
 command: ["python", "src/app.py"]
```

I used it recently to inject a `.pem` certificate into the container before the
main execution.

The script must conclude with `exec "$@"` because it receives the value of the
`command` key in the Compose file as its argument. E.g.

```sh
cat /etc/ssl/certs/ca-certificates.crt /zscaler.pem > /tmp/combined-certs.pem
export REQUESTS_CA_BUNDLE=/tmp/combined-certs.pem
export SSL_CERT_FILE=/tmp/combined-certs.pem

pip install -r requirements.txt

exec "$@"
```