114 lines
3.1 KiB
Go
114 lines
3.1 KiB
Go
// Copyright 2016-2018, Pulumi Corporation. All rights reserved.
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// Package dotconv converts a resource graph into its DOT digraph equivalent. This is useful for integration with
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// various visualization tools, like Graphviz. Please see http://www.graphviz.org/content/dot-language for a thorough
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// specification of the DOT file format.
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package dotconv
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import (
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"bufio"
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"fmt"
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"io"
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"strconv"
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"github.com/pulumi/pulumi/pkg/graph"
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"github.com/pulumi/pulumi/pkg/util/contract"
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)
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// Print prints a resource graph.
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func Print(g graph.Graph, w io.Writer) error {
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// Allocate a new writer. In general, we will ignore write errors throughout this function, for simplicity, opting
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// instead to return the result of flushing the buffer at the end, which is generally latching.
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b := bufio.NewWriter(w)
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// Print the graph header.
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if _, err := b.WriteString("strict digraph {\n"); err != nil {
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return err
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}
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// Initialize the frontier with unvisited graph vertices.
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queued := make(map[graph.Vertex]bool)
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frontier := make([]graph.Vertex, 0, len(g.Roots()))
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for _, root := range g.Roots() {
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to := root.To()
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queued[to] = true
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frontier = append(frontier, to)
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}
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// For now, we auto-generate IDs.
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// TODO[pulumi/pulumi#76]: use the object URNs instead, once we have them.
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c := 0
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ids := make(map[graph.Vertex]string)
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getID := func(v graph.Vertex) string {
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if id, has := ids[v]; has {
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return id
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}
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id := "Resource" + strconv.Itoa(c)
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c++
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ids[v] = id
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return id
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}
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// Now, until the frontier is empty, emit entries into the stream.
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indent := " "
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emitted := make(map[graph.Vertex]bool)
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for len(frontier) > 0 {
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// Dequeue the head of the frontier.
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v := frontier[0]
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frontier = frontier[1:]
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contract.Assert(!emitted[v])
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emitted[v] = true
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// Get and lazily allocate the ID for this vertex.
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id := getID(v)
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// Print this vertex; first its "label" (type) and then its direct dependencies.
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// IDEA: consider serializing properties on the node also.
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if _, err := b.WriteString(fmt.Sprintf("%v%v", indent, id)); err != nil {
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return err
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}
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if label := v.Label(); label != "" {
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if _, err := b.WriteString(fmt.Sprintf(" [label=\"%v\"]", label)); err != nil {
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return err
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}
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}
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if _, err := b.WriteString(";\n"); err != nil {
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return err
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}
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// Now print out all dependencies as "ID -> {A ... Z}".
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outs := v.Outs()
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if len(outs) > 0 {
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base := fmt.Sprintf("%v%v", indent, id)
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// Print the ID of each dependency and, for those we haven't seen, add them to the frontier.
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for _, out := range outs {
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to := out.To()
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if _, err := b.WriteString(fmt.Sprintf("%s -> %s", base, getID(to))); err != nil {
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return err
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}
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if out.Color() != "" {
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if _, err := b.WriteString(fmt.Sprintf(" [color=\"%s\"]", out.Color())); err != nil {
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return err
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}
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}
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if _, err := b.WriteString(";\n"); err != nil {
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return err
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}
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if _, q := queued[to]; !q {
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queued[to] = true
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frontier = append(frontier, to)
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}
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}
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}
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}
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// Finish the graph.
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if _, err := b.WriteString("}\n"); err != nil {
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return err
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}
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return b.Flush()
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}
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