Controller architecture » History » Revision 3
Revision 2 (Tom Clegg, 01/10/2019 03:37 PM) → Revision 3/6 (Tom Clegg, 01/14/2019 09:46 PM)
h1. Controller architecture **arvados** (Apache2) defines a DBClient interface with the Arvados database operations, like CollectionList(Context, ListOptions) (CollectionListResponse, error). It also defines a Context interface that adds permission context to context.Context. **rpc** (Apache2) implements arvados.DBClient by calling an Arvados controller's http service. It also provides an implementation of arvados.Context that wraps a token so it can be forwarded to the remote. **pgdb** implements arvados.DBClient by doing PostgreSQL queries. Enforces permissions, validations, model integrity. It also implements a database-backed arvados.Context. **pgdb/container** implements the Container/ContainerRequest methods of pgdb.DBClient. Also: pgdb/collection, pgdb/user, etc. **pgdbrow** provides generic functions (used by pgdb/container et al.) to translate between object fields/transformations and SQL rows/statements. **federation** implements arvados.DBClient by fanning out to multiple arvados.DBClient backends (typically one local and several remotes, to suit cluster config). Federation-unaware APIs fall through to a default pgdb.DBClient. **router** maps HTTP requests to actions by checking auth scope and calling the appropriate arvados.DBClient method. **server** listens on a port and serves http requests. Handler gets an arvados.Context from the (caller-provided) arvados.DBClient, and passes the request to a Router. **controller** reads a cluster config file and starts a server backed by a federation.DBClient. Diagram: https://docs.google.com/drawings/d/1Qsj7Re4kE1tNMy7RaNR_dc9U5t6vswMJOhCI2YlbsCM/edit?usp=sharing