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// Copyright (c) 2019 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package dig
import (
"io"
"strconv"
"text/template"
"go.uber.org/dig/internal/dot"
)
// A VisualizeOption modifies the default behavior of Visualize.
type VisualizeOption interface {
applyVisualizeOption(*visualizeOptions)
}
type visualizeOptions struct {
VisualizeError error
}
type visualizeOptionFunc func(*visualizeOptions)
func (f visualizeOptionFunc) applyVisualizeOption(opts *visualizeOptions) { f(opts) }
// VisualizeError includes a visualization of the given error in the output of
// Visualize if an error was returned by Invoke or Provide.
//
// if err := c.Provide(...); err != nil {
// dig.Visualize(c, w, dig.VisualizeError(err))
// }
//
// This option has no effect if the error was nil or if it didn't contain any
// information to visualize.
func VisualizeError(err error) VisualizeOption {
return visualizeOptionFunc(func(opts *visualizeOptions) {
opts.VisualizeError = err
})
}
func updateGraph(dg *dot.Graph, err error) error {
var errors []errVisualizer
// Unwrap error to find the root cause.
for {
if ev, ok := err.(errVisualizer); ok {
errors = append(errors, ev)
}
e, ok := err.(causer)
if !ok {
break
}
err = e.cause()
}
// If there are no errVisualizers included, we do not modify the graph.
if len(errors) == 0 {
return nil
}
// We iterate in reverse because the last element is the root cause.
for i := len(errors) - 1; i >= 0; i-- {
errors[i].updateGraph(dg)
}
// Remove non-error entries from the graph for readability.
dg.PruneSuccess()
return nil
}
var _graphTmpl = template.Must(
template.New("DotGraph").
Funcs(template.FuncMap{
"quote": strconv.Quote,
}).
Parse(`digraph {
rankdir=RL;
graph [compound=true];
{{range $g := .Groups}}
{{- quote .String}} [{{.Attributes}}];
{{range .Results}}
{{- quote $g.String}} -> {{quote .String}};
{{end}}
{{end -}}
{{range $index, $ctor := .Ctors}}
subgraph cluster_{{$index}} {
constructor_{{$index}} [shape=plaintext label={{quote .Name}}];
{{with .ErrorType}}color={{.Color}};{{end}}
{{range .Results}}
{{- quote .String}} [{{.Attributes}}];
{{end}}
}
{{range .Params}}
constructor_{{$index}} -> {{quote .String}} [ltail=cluster_{{$index}}{{if .Optional}} style=dashed{{end}}];
{{end}}
{{range .GroupParams}}
constructor_{{$index}} -> {{quote .String}} [ltail=cluster_{{$index}}];
{{end -}}
{{end}}
{{range .Failed.TransitiveFailures}}
{{- quote .String}} [color=orange];
{{end -}}
{{range .Failed.RootCauses}}
{{- quote .String}} [color=red];
{{end}}
}`))
// Visualize parses the graph in Container c into DOT format and writes it to
// io.Writer w.
func Visualize(c *Container, w io.Writer, opts ...VisualizeOption) error {
dg := c.createGraph()
var options visualizeOptions
for _, o := range opts {
o.applyVisualizeOption(&options)
}
if options.VisualizeError != nil {
if err := updateGraph(dg, options.VisualizeError); err != nil {
return err
}
}
return _graphTmpl.Execute(w, dg)
}
// CanVisualizeError returns true if the error is an errVisualizer.
func CanVisualizeError(err error) bool {
for {
if _, ok := err.(errVisualizer); ok {
return true
}
e, ok := err.(causer)
if !ok {
break
}
err = e.cause()
}
return false
}
func (c *Container) createGraph() *dot.Graph {
dg := dot.NewGraph()
for _, n := range c.nodes {
dg.AddCtor(newDotCtor(n), n.paramList.DotParam(), n.resultList.DotResult())
}
return dg
}
func newDotCtor(n *node) *dot.Ctor {
return &dot.Ctor{
ID: n.id,
Name: n.location.Name,
Package: n.location.Package,
File: n.location.File,
Line: n.location.Line,
}
}
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