This makes separating middlewares from the core api easier.
As an example, the authorization middleware is moved to
it's own package.
Initialize all static middlewares when the server is created, reducing
allocations every time a route is wrapper with the middlewares.
Signed-off-by: David Calavera <david.calavera@gmail.com>
Changes how the Engine interacts with Registry servers on image pull.
Previously, Engine sent a User-Agent string to the Registry server
that included only the Engine's version information. This commit
appends to that string the fields from the User-Agent sent by the
client (e.g., Compose) of the Engine. This allows Registry server
operators to understand what tools are actually generating pulls on
their registries.
Signed-off-by: Mike Goelzer <mgoelzer@docker.com>
