Prepare and reuse environments

from contree_sdk import Contree

client = Contree()
base = await client.images.oci("docker.io/library/alpine:3.19")
prepared = await base.run(
    shell="mkdir -p /opt/example && printf 'version=1\\n' > /opt/example/config.ini",
    disposable=False,
    timeout=60,
)
if prepared.exit_code != 0 or prepared.uuid is None:
    raise RuntimeError("Preparation failed or returned no saved image")
checkpoint_uuid = prepared.uuid

checkpoint = await client.images.use(checkpoint_uuid, strict=True)
verification = await checkpoint.run(
    shell="cat /opt/example/config.ini",
    disposable=True,
    timeout=30,
)
if verification.exit_code != 0:
    raise RuntimeError(f"Configuration read failed: {verification.stderr}")
if verification.stdout != "version=1\n":
    raise RuntimeError("The saved configuration has an unexpected value")
if verification.uuid is not None:
    raise RuntimeError("A disposable read unexpectedly returned a saved image")

print(verification.stdout, end="")

version=1