test/e2e: add random testnet generator (#5479)

Closes #5291. Adds a randomized testnet generator. Nightly CI job will be submitted separately. A few of the testnets can be a bit flaky, even after disabling known-faulty behavior and making minor tweaks, and the larger networks may be too resource-intensive to run in CI - this will be optimized separately.

test/e2e/generator/main.go

@@ -0,0 +1,97 @@
+//nolint: gosec
+package main
+
+import (
+	"fmt"
+	"math"
+	"math/rand"
+	"os"
+	"path/filepath"
+
+	"github.com/spf13/cobra"
+	"github.com/tendermint/tendermint/libs/log"
+)
+
+const (
+	randomSeed int64 = 4827085738
+)
+
+var logger = log.NewTMLogger(log.NewSyncWriter(os.Stdout))
+
+func main() {
+	NewCLI().Run()
+}
+
+// CLI is the Cobra-based command-line interface.
+type CLI struct {
+	root *cobra.Command
+}
+
+// NewCLI sets up the CLI.
+func NewCLI() *CLI {
+	cli := &CLI{}
+	cli.root = &cobra.Command{
+		Use:           "generator",
+		Short:         "End-to-end testnet generator",
+		SilenceUsage:  true,
+		SilenceErrors: true, // we'll output them ourselves in Run()
+		RunE: func(cmd *cobra.Command, args []string) error {
+			dir, err := cmd.Flags().GetString("dir")
+			if err != nil {
+				return err
+			}
+			groups, err := cmd.Flags().GetInt("groups")
+			if err != nil {
+				return err
+			}
+			return cli.generate(dir, groups)
+		},
+	}
+
+	cli.root.PersistentFlags().StringP("dir", "d", "", "Output directory for manifests")
+	_ = cli.root.MarkPersistentFlagRequired("dir")
+	cli.root.PersistentFlags().IntP("groups", "g", 0, "Number of groups")
+
+	return cli
+}
+
+// generate generates manifests in a directory.
+func (cli *CLI) generate(dir string, groups int) error {
+	err := os.MkdirAll(dir, 0755)
+	if err != nil {
+		return err
+	}
+
+	manifests, err := Generate(rand.New(rand.NewSource(randomSeed)))
+	if err != nil {
+		return err
+	}
+	if groups <= 0 {
+		for i, manifest := range manifests {
+			err = manifest.Save(filepath.Join(dir, fmt.Sprintf("gen-%04d.toml", i)))
+			if err != nil {
+				return err
+			}
+		}
+	} else {
+		groupSize := int(math.Ceil(float64(len(manifests)) / float64(groups)))
+		for g := 0; g < groups; g++ {
+			for i := 0; i < groupSize && g*groupSize+i < len(manifests); i++ {
+				manifest := manifests[g*groupSize+i]
+				err = manifest.Save(filepath.Join(dir, fmt.Sprintf("gen-group%02d-%04d.toml", g, i)))
+				if err != nil {
+					return err
+				}
+			}
+		}
+	}
+	return nil
+}
+
+// Run runs the CLI.
+func (cli *CLI) Run() {
+	if err := cli.root.Execute(); err != nil {
+		logger.Error(err.Error())
+		os.Exit(1)
+	}
+}