read-file-to-env -- Read files into environment variables and execute command
Example use:
read-file-to-env -one-line=HOST=/etc/hostname sh -c 'echo host=$HOST'
Use with systemd credentials, useful for example when a container image can only receive things via environment variables. For example, postgres:14 (see https://github.com/docker-library/docs/blob/master/postgres/README.md for background). For container images you control, please support reading from files.
[Service]
# only relevant lines shown, see `podman generate systemd`
LoadCredential=pg-user:/etc/keys/postgres-admin-username
LoadCredential=pg-password:/etc/keys/postgres-admin-password
ExecStart=read-file-to-env \
-one-line=POSTGRES_USER=${CREDENTIALS_DIRECTORY}/pg-user \
-one-line=POSTGRES_PASSWORD=${CREDENTIALS_DIRECTORY}/pg-password \
-- \
podman run \
... \
--env=POSTGRES_USER \
--env=POSTGRES_PASSWORD \
postgres:14
