| // Copyright 2018 The LUCI Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| // Package graph implements a DAG used internally to represent config objects. |
| // |
| // All entities in the LUCI config are represented by nodes in a graph. Nodes |
| // are linked with directional edges. Cycles are forbidden. Each edge is |
| // annotated with a name of the relation that added it (e.g. "triggered_by"). |
| // There can be multiple edges between a given pair of nodes, e.g. |
| // "triggered_by" and "triggers" edges between a builder(...) and a |
| // trigger(...). When detecting cycles or traversing the graph, edge annotations |
| // are not considered. They are used only to improve error messages when |
| // reporting dangling edges (e.g. Builder X references undefined trigger T via |
| // "triggered_by"). |
| // |
| // Each node: |
| // * Has a unique identifier, called key. A key is a list of |
| // (string kind, string id) pairs. Once constructed, a key is an opaque |
| // label (e.g. there's no way to explore what's inside the key through |
| // Starlark, to keep the API simple). Examples of keys: |
| // [luci.bucket("ci")] |
| // [luci.bucket("ci"), luci.builder("infra-builder")] |
| // * Has a props dict of arbitrary properties (all keys are strings, values |
| // are arbitrary). |
| // * Has a captured stack trace of where in Starlark it was defined (for error |
| // messages). |
| // * Is immutable |
| // |
| // Structs exposed by this package are not safe for concurrent use without |
| // external locking. |
| package graph |
