pulumi/pkg/graph/graph.go

49 lines
2.6 KiB
Go

// Copyright 2016-2018, Pulumi Corporation.
//
// 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 defines resource graphs. Each graph is directed and acyclic, and the nodes have been topologically
// sorted based on dependencies (edges) between them. Each node in the graph has a type and a set of properties.
//
// There are two forms of graph: complete and incomplete. A complete graph is one in which all nodes and their property
// values are known. An incomplete graph is one where two uncertainties may arise: (1) an edge might be "conditional",
// indicating that its presence or absence is dependent on a piece of information not yet available (like an output
// property from a resource), and/or (2) a property may either be similarly conditional or computed as an output value.
//
// In general, programs may be evaluated to produce graphs. These may then be compared to other graphs to produce
// and/or carry out deployment plans. This package therefore also exposes operations necessary for diffing graphs.
package graph
// Graph is an instance of a resource digraph. Each is associated with a single program input, along
// with a set of optional arguments used to evaluate it, along with the output DAG with node types and properties.
type Graph interface {
Roots() []Edge // the root edges.
}
// Vertex is a single vertex within an overall resource graph.
type Vertex interface {
Data() interface{} // arbitrary data associated with this vertex.
Label() string // the vertex's label.
Ins() []Edge // incoming edges from other vertices within the graph to this vertex.
Outs() []Edge // outgoing edges from this vertex to other vertices within the graph.
}
// Edge is a directed edge from one vertex to another.
type Edge interface {
Data() interface{} // arbitrary data associated with this edge.
Label() string // this edge's label.
To() Vertex // the vertex this edge connects to.
From() Vertex // the vertex this edge connects from.
Color() string // an optional color for this edge, for when this graph is displayed.
}