This change is in preparation of deprecating support for old manifests.
Currently the daemon's ID is based on the trust-key ID, which will be
removed once we fully deprecate support for old manifests (the trust
key is currently only used in tests).
This patch:
- looks if a trust-key is present; if so, it migrates the trust-key
ID to the new "engine-id" file within the daemon's root.
- if no trust-key is present (so in case it's a "fresh" install), we
generate a UUID instead and use that as ID.
The migration is to prevent engines from getting a new ID on upgrades;
while we don't provide any guarantees on the engine's ID, users may
expect the ID to be "stable" (not change) between upgrades.
A test has been added, which can be ran with;
make DOCKER_GRAPHDRIVER=vfs TEST_FILTER='TestConfigDaemonID' test-integration
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
