Started working on viz subcommand

Signed-off-by: Benjamín Guzmán <bg@benjaminguzman.dev>

cmd/compose/alpha.go

@@ -34,6 +34,7 @@ func alphaCommand(p *ProjectOptions, backend api.Service) *cobra.Command {
 	cmd.AddCommand(
 		watchCommand(p, backend),
 		dryRunRedirectCommand(p),
+		vizCommand(p),
 	)
 	return cmd
 }

cmd/compose/viz.go

@@ -0,0 +1,191 @@
+/*
+   Copyright 2023 Docker Compose CLI 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 compose
+
+import (
+	"context"
+	"fmt"
+	"github.com/compose-spec/compose-go/types"
+	"github.com/spf13/cobra"
+	"os"
+	"strconv"
+	"strings"
+)
+
+type vizOptions struct {
+	*ProjectOptions
+	includeNetworks  bool
+	includePorts     bool
+	includeImageName bool
+	indentationStr   string
+}
+
+// maps a service with the services it depends on
+type vizGraph map[*types.ServiceConfig][]*types.ServiceConfig
+
+func vizCommand(p *ProjectOptions) *cobra.Command {
+	opts := vizOptions{
+		ProjectOptions: p,
+	}
+	var indentationSize int
+	var useSpaces bool
+
+	cmd := &cobra.Command{
+		Use:   "viz [OPTIONS]",
+		Short: "EXPERIMENTAL - Generate a graphviz graph from your compose file",
+		PreRunE: Adapt(func(ctx context.Context, args []string) error {
+			var err error
+			opts.indentationStr, err = preferredIndentationStr(indentationSize, useSpaces)
+			return err
+		}),
+		RunE: Adapt(func(ctx context.Context, args []string) error {
+			return runViz(ctx, &opts)
+		}),
+	}
+
+	cmd.Flags().BoolVar(&opts.includePorts, "ports", false, "Include service's exposed ports in output graph")
+	cmd.Flags().BoolVar(&opts.includeNetworks, "networks", false, "Include service's attached networks in output graph")
+	cmd.Flags().BoolVar(&opts.includeImageName, "image", false, "Include service's image name in output graph")
+	cmd.Flags().IntVar(&indentationSize, "indentation-size", 1, "Number of tabs or spaces to use for indentation")
+	cmd.Flags().BoolVar(&useSpaces, "spaces", false, "If given, space character ' ' will be used to indent,\notherwise tab character '\\t' will be used")
+	return cmd
+}
+
+func runViz(ctx context.Context, opts *vizOptions) error {
+	_, _ = fmt.Fprintln(os.Stderr, "viz command is EXPERIMENTAL")
+	project, err := opts.ToProject(nil)
+	if err != nil {
+		return err
+	}
+
+	// build graph
+	graph := make(vizGraph)
+	for i, serviceConfig := range project.Services {
+		serviceConfigPtr := &project.Services[i]
+		graph[serviceConfigPtr] = make([]*types.ServiceConfig, 0, len(serviceConfig.DependsOn))
+		for dependencyName := range serviceConfig.DependsOn {
+			// no error should be returned since dependencyName should exist
+			dependency, _ := project.GetService(dependencyName)
+			graph[serviceConfigPtr] = append(graph[serviceConfigPtr], &dependency)
+		}
+	}
+
+	// build graphviz graph
+	var graphBuilder strings.Builder
+	graphBuilder.WriteString("digraph " + project.Name + " {\n")
+	graphBuilder.WriteString(opts.indentationStr + "layout=dot;\n")
+	addNodes(&graphBuilder, graph, opts)
+	graphBuilder.WriteRune('\n')
+	addEdges(&graphBuilder, graph, opts)
+	graphBuilder.WriteString("}\n")
+
+	fmt.Println(graphBuilder.String())
+
+	return nil
+}
+
+// addNodes adds the corresponding graphviz representation of all the nodes in the given graph to the graphBuilder
+// returns the same graphBuilder
+func addNodes(graphBuilder *strings.Builder, graph vizGraph, opts *vizOptions) *strings.Builder {
+	for serviceNode := range graph {
+		// write:
+		// "service name" [style="filled" label<<font point-size="15">service name</font>
+		graphBuilder.WriteString(opts.indentationStr)
+		writeQuoted(graphBuilder, serviceNode.Name)
+		graphBuilder.WriteString(" [style=\"filled\" label=<<font point-size=\"15\">")
+		graphBuilder.WriteString(serviceNode.Name)
+		graphBuilder.WriteString("</font>")
+
+		if opts.includeNetworks && len(serviceNode.Networks) > 0 {
+			graphBuilder.WriteString("<font point-size=\"10\">")
+			graphBuilder.WriteString("<br/><br/><b>Networks:</b>")
+			for _, networkName := range serviceNode.NetworksByPriority() {
+				graphBuilder.WriteString("<br/>")
+				graphBuilder.WriteString(networkName)
+			}
+			graphBuilder.WriteString("</font>")
+		}
+
+		if opts.includePorts && len(serviceNode.Ports) > 0 {
+			graphBuilder.WriteString("<font point-size=\"10\">")
+			graphBuilder.WriteString("<br/><br/><b>Ports:</b>")
+			for _, portConfig := range serviceNode.Ports {
+				graphBuilder.WriteString("<br/>")
+				if len(portConfig.HostIP) > 0 {
+					graphBuilder.WriteString(portConfig.HostIP)
+					graphBuilder.WriteRune(':')
+				}
+				graphBuilder.WriteString(portConfig.Published)
+				graphBuilder.WriteRune(':')
+				graphBuilder.WriteString(strconv.Itoa(int(portConfig.Target)))
+				graphBuilder.WriteString(" (")
+				graphBuilder.WriteString(portConfig.Protocol)
+				graphBuilder.WriteString(", ")
+				graphBuilder.WriteString(portConfig.Mode)
+				graphBuilder.WriteString(")")
+			}
+			graphBuilder.WriteString("</font>")
+		}
+
+		if opts.includeImageName {
+			graphBuilder.WriteString("<font point-size=\"10\">")
+			graphBuilder.WriteString("<br/><br/><b>Image:</b><br/>")
+			graphBuilder.WriteString(serviceNode.Image)
+			graphBuilder.WriteString("</font>")
+		}
+
+		graphBuilder.WriteString(">];\n")
+	}
+
+	return graphBuilder
+}
+
+// addEdges adds the corresponding graphviz representation of all edges in the given graph to the graphBuilder
+// returns the same graphBuilder
+func addEdges(graphBuilder *strings.Builder, graph vizGraph, opts *vizOptions) *strings.Builder {
+	for parent, children := range graph {
+		for _, child := range children {
+			graphBuilder.WriteString(opts.indentationStr)
+			writeQuoted(graphBuilder, parent.Name)
+			graphBuilder.WriteString(" -> ")
+			writeQuoted(graphBuilder, child.Name)
+			graphBuilder.WriteString(";\n")
+		}
+	}
+
+	return graphBuilder
+}
+
+// writeQuoted writes "str" to builder
+func writeQuoted(builder *strings.Builder, str string) {
+	builder.WriteRune('"')
+	builder.WriteString(str)
+	builder.WriteRune('"')
+}
+
+// preferredIndentationStr returns a single string given the indentation preference
+func preferredIndentationStr(size int, useSpace bool) (string, error) {
+	if size < 0 {
+		return "", fmt.Errorf("invalid indentation size: %d", size)
+	}
+
+	indentationStr := "\t"
+	if useSpace {
+		indentationStr = " "
+	}
+	return strings.Repeat(indentationStr, size), nil
+}