feat(confix): copy confix from cosmos sdk (cometbft#3036)

# Confix

`Confix` is a configuration management tool that allows you to manage
your configuration via CLI.

It is based on the [CometBFT RFC
019](https://github.com/cometbft/cometbft/blob/5013bc3f4a6d64dcc2bf02ccc002ebc9881c62e4/docs/rfc/rfc-019-config-version.md).

## Usage

### Get

Get a configuration value, e.g.:

```shell
cometbft config get pruning # gets the value pruning
cometbft config get chain-id # gets the value chain-id
```

### Set

Set a configuration value, e.g.:

```shell
cometbft config set pruning "enabled" # sets the value pruning
cometbft config set chain-id "foo-1" # sets the value chain-id
```
### Migrate

Migrate a configuration file to a new version:

```shell
cometbft config migrate v0.38 # migrates defaultHome/config/config.toml to the latest v0.38 config
```

### Diff

Get the diff between a given configuration file and the default
configuration
file, e.g.:

```shell
cometbft config diff v0.38 # gets the diff between defaultHome/config/config.toml and the latest v0.38 config
```

### View

View a configuration file, e.g:

```shell
cometbft config view # views the current config
```

## Credits

This project is based on the [CometBFT RFC
019](https://github.com/cometbft/cometbft/blob/5013bc3f4a6d64dcc2bf02ccc002ebc9881c62e4/docs/rfc/rfc-019-config-version.md)
and their own implementation of
[confix](https://github.com/cometbft/cometbft/blob/v0.36.x/scripts/confix/confix.go).
Most of the code is copied over from [Cosmos
SDK](https://github.com/cosmos/cosmos-sdk/tree/main/tools/confix).

---

#### PR checklist

- [ ] ~~Tests written/updated~~
- [ ] ~~Changelog entry added in `.changelog` (we use
[unclog](https://github.com/informalsystems/unclog) to manage our
changelog)~~
- [ ] ~~Updated relevant documentation (`docs/` or `spec/`) and code
comments~~
- [x] Title follows the [Conventional
Commits](https://www.conventionalcommits.org/en/v1.0.0/) spec

.changelog/unreleased/improvements/3036-confix.md

@@ -0,0 +1,3 @@
+- `[cmd/cometbft]` Add `cometbft config` cmd to view, modify and
+  upgrade configs across different versions
+  ([\#3036](https://github.com/cometbft/cometbft/pull/3036))

.golangci.yml

@@ -94,8 +94,13 @@ linters-settings:
           - "!$test"
         allow:
           - $gostd
+          - github.com/BurntSushi/toml
+          - github.com/Masterminds/semver/v3
+          - github.com/btcsuite/btcd/btcec/v2
           - github.com/cometbft
           - github.com/cosmos
+          - github.com/creachadair/atomicfile
+          - github.com/creachadair/tomledit
           - github.com/btcsuite/btcd/btcec/v2
           - github.com/BurntSushi/toml
           - github.com/dgraph-io/badger/v4
@@ -108,9 +113,9 @@ linters-settings:
           - github.com/hashicorp/golang-lru/v2
           - github.com/lib/pq
           - github.com/libp2p/go-buffer-pool
-          - github.com/Masterminds/semver/v3
           - github.com/minio/highwayhash
           - github.com/oasisprotocol/curve25519-voi
+          - github.com/pelletier/go-toml/v2
           - github.com/pkg/errors
           - github.com/prometheus
           - github.com/rcrowley/go-metrics

cmd/cometbft/commands/config/common.go

@@ -0,0 +1,18 @@
+package config
+
+import (
+	"path/filepath"
+
+	"github.com/spf13/cobra"
+
+	"github.com/cometbft/cometbft/cmd/cometbft/commands"
+	cfg "github.com/cometbft/cometbft/config"
+)
+
+func defaultConfigPath(cmd *cobra.Command) string {
+	home, err := commands.ConfigHome(cmd)
+	if err != nil {
+		return ""
+	}
+	return filepath.Join(home, cfg.DefaultConfigDir, cfg.DefaultConfigFileName)
+}

cmd/cometbft/commands/config/config.go

@@ -0,0 +1,24 @@
+package config
+
+import (
+	"github.com/spf13/cobra"
+)
+
+// Command contains all the confix commands
+// These command can be used to interactively update a config value.
+func Command() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "config",
+		Short: "Utilities for managing configuration",
+	}
+
+	cmd.AddCommand(
+		MigrateCommand(),
+		DiffCommand(),
+		GetCommand(),
+		SetCommand(),
+		ViewCommand(),
+	)
+
+	return cmd
+}

cmd/cometbft/commands/config/diff.go

@@ -0,0 +1,55 @@
+package config
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+	"golang.org/x/exp/maps"
+
+	"github.com/cometbft/cometbft/internal/confix"
+)
+
+// DiffCommand creates a new command for comparing configuration files.
+func DiffCommand() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "diff [target-version] <config-path>",
+		Short: "Outputs all config values that are different from the default.",
+		Long:  "This command compares the configuration file with the defaults and outputs any differences.",
+		Args:  cobra.MinimumNArgs(1),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			var configPath string
+			if len(args) > 1 {
+				configPath = args[1]
+			} else {
+				configPath = defaultConfigPath(cmd)
+			}
+
+			targetVersion := args[0]
+			if _, ok := confix.Migrations[targetVersion]; !ok {
+				return fmt.Errorf("unknown version %q, supported versions are: %q", targetVersion, maps.Keys(confix.Migrations))
+			}
+
+			targetVersionFile, err := confix.LoadLocalConfig(targetVersion + ".toml")
+			if err != nil {
+				return fmt.Errorf("failed to load internal config: %w", err)
+			}
+
+			rawFile, err := confix.LoadConfig(configPath)
+			if err != nil {
+				return fmt.Errorf("failed to load config: %w", err)
+			}
+
+			diff := confix.DiffValues(rawFile, targetVersionFile)
+			if len(diff) == 0 {
+				fmt.Print("All config values are the same as the defaults.\n")
+			}
+
+			fmt.Print("The following config values are different from the defaults:\n")
+
+			confix.PrintDiff(cmd.OutOrStdout(), diff)
+			return nil
+		},
+	}
+
+	return cmd
+}

cmd/cometbft/commands/config/migrate.go

@@ -0,0 +1,69 @@
+package config
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/spf13/cobra"
+	"golang.org/x/exp/maps"
+
+	"github.com/cometbft/cometbft/internal/confix"
+)
+
+var (
+	FlagStdOut       bool
+	FlagVerbose      bool
+	FlagSkipValidate bool
+)
+
+func MigrateCommand() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "migrate [target-version] <config-path>",
+		Short: "Migrate configuration file to the specified version",
+		Long: `Migrate the contents of the configuration to the specified version.
+The output is written in-place unless --stdout is provided.
+In case of any error in updating the file, no output is written.`,
+		Args: cobra.MinimumNArgs(1),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			var configPath string
+			if len(args) > 1 {
+				configPath = args[1]
+			} else {
+				configPath = defaultConfigPath(cmd)
+			}
+
+			targetVersion := args[0]
+			plan, ok := confix.Migrations[targetVersion]
+			if !ok {
+				return fmt.Errorf("unknown version %q, supported versions are: %q", targetVersion, maps.Keys(confix.Migrations))
+			}
+
+			rawFile, err := confix.LoadConfig(configPath)
+			if err != nil {
+				return fmt.Errorf("failed to load config: %w", err)
+			}
+
+			ctx := context.Background()
+			if FlagVerbose {
+				ctx = confix.WithLogWriter(ctx, cmd.ErrOrStderr())
+			}
+
+			outputPath := configPath
+			if FlagStdOut {
+				outputPath = ""
+			}
+
+			if err := confix.Upgrade(ctx, plan(rawFile, targetVersion), configPath, outputPath, FlagSkipValidate); err != nil {
+				return fmt.Errorf("failed to migrate config: %w", err)
+			}
+
+			return nil
+		},
+	}
+
+	cmd.Flags().BoolVar(&FlagStdOut, "stdout", false, "print the updated config to stdout")
+	cmd.Flags().BoolVar(&FlagVerbose, "verbose", false, "log changes to stderr")
+	cmd.Flags().BoolVar(&FlagSkipValidate, "skip-validate", false, "skip configuration validation (allows to migrate unknown configurations)")
+
+	return cmd
+}

cmd/cometbft/commands/config/mutate.go

@@ -0,0 +1,144 @@
+package config
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/creachadair/tomledit"
+	"github.com/creachadair/tomledit/parser"
+	"github.com/creachadair/tomledit/transform"
+	"github.com/spf13/cobra"
+
+	"github.com/cometbft/cometbft/internal/confix"
+)
+
+// SetCommand returns a CLI command to interactively update an application config value.
+func SetCommand() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "set [config] [key] [value]",
+		Short: "Set a config value",
+		Long:  "Set a config value. The [config] is an optional absolute path to the config file (default: `~/.cometbft/config/config.toml`)",
+		Args:  cobra.MinimumNArgs(2),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			var (
+				filename, inputValue string
+				key                  []string
+			)
+			switch len(args) {
+			case 2:
+				{
+					filename = defaultConfigPath(cmd)
+					// parse key e.g mempool.size -> [mempool, size]
+					key = strings.Split(args[0], ".")
+					inputValue = args[1]
+				}
+			case 3:
+				{
+					filename, inputValue = args[0], args[2]
+					key = strings.Split(args[1], ".")
+				}
+			default:
+				return errors.New("expected 2 or 3 arguments")
+			}
+
+			plan := transform.Plan{
+				{
+					Desc: fmt.Sprintf("update %q=%q in %s", key, inputValue, filename),
+					T: transform.Func(func(_ context.Context, doc *tomledit.Document) error {
+						results := doc.Find(key...)
+						if len(results) == 0 {
+							return fmt.Errorf("key %q not found", key)
+						} else if len(results) > 1 {
+							return fmt.Errorf("key %q is ambiguous", key)
+						}
+
+						value, err := parser.ParseValue(inputValue)
+						if err != nil {
+							value = parser.MustValue(`"` + inputValue + `"`)
+						}
+
+						if ok := transform.InsertMapping(results[0].Section, &parser.KeyValue{
+							Block: results[0].Block,
+							Name:  results[0].Name,
+							Value: value,
+						}, true); !ok {
+							return errors.New("failed to set value")
+						}
+
+						return nil
+					}),
+				},
+			}
+
+			outputPath := filename
+			if FlagStdOut {
+				outputPath = ""
+			}
+
+			ctx := cmd.Context()
+			if FlagVerbose {
+				ctx = confix.WithLogWriter(ctx, cmd.ErrOrStderr())
+			}
+
+			return confix.Upgrade(ctx, plan, filename, outputPath, FlagSkipValidate)
+		},
+	}
+
+	cmd.Flags().BoolVar(&FlagStdOut, "stdout", false, "print the updated config to stdout")
+	cmd.Flags().BoolVarP(&FlagVerbose, "verbose", "v", false, "log changes to stderr")
+	cmd.Flags().BoolVarP(&FlagSkipValidate, "skip-validate", "s", false, "skip configuration validation (allows to mutate unknown configurations)")
+
+	return cmd
+}
+
+// GetCommand returns a CLI command to interactively get an application config value.
+func GetCommand() *cobra.Command {
+	cmd := &cobra.Command{
+		Use:   "get [config] [key]",
+		Short: "Get a config value",
+		Long:  "Get a config value. The [config] is an optional absolute path to the config file (default: `~/.cometbft/config/config.toml`)",
+		Args:  cobra.MinimumNArgs(1),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			var (
+				filename, key string
+				keys          []string
+			)
+			switch len(args) {
+			case 1:
+				{
+					filename = defaultConfigPath(cmd)
+					// parse key e.g mempool.size -> [mempool, size]
+					key = args[0]
+					keys = strings.Split(key, ".")
+				}
+			case 2:
+				{
+					filename = args[0]
+					key = args[1]
+					keys = strings.Split(key, ".")
+				}
+			default:
+				return errors.New("expected 1 or 2 arguments")
+			}
+
+			doc, err := confix.LoadConfig(filename)
+			if err != nil {
+				return fmt.Errorf("failed to load config: %w", err)
+			}
+
+			results := doc.Find(keys...)
+			if len(results) == 0 {
+				return fmt.Errorf("key %q not found", key)
+			} else if len(results) > 1 {
+				return fmt.Errorf("key %q is ambiguous", key)
+			}
+
+			fmt.Printf("%s\n", results[0].Value.String())
+			return nil
+		},
+	}
+
+	return cmd
+}

cmd/cometbft/commands/config/view.go

@@ -0,0 +1,52 @@
+package config
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+
+	"github.com/pelletier/go-toml/v2"
+	"github.com/spf13/cobra"
+)
+
+func ViewCommand() *cobra.Command {
+	flagOutputFormat := "output-format"
+
+	cmd := &cobra.Command{
+		Use:   "view [config]",
+		Short: "View the config file",
+		Long:  "View the config file. The [config] is an optional absolute path to the config file (default: `~/.cometbft/config/config.toml`)",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			var filename string
+			if len(args) > 0 {
+				filename = args[0]
+			} else {
+				filename = defaultConfigPath(cmd)
+			}
+
+			file, err := os.ReadFile(filename)
+			if err != nil {
+				return err
+			}
+
+			if format, _ := cmd.Flags().GetString(flagOutputFormat); format == "toml" {
+				cmd.Println(string(file))
+				return nil
+			}
+
+			var v any
+			if err := toml.Unmarshal(file, &v); err != nil {
+				return fmt.Errorf("failed to decode config file: %w", err)
+			}
+
+			e := json.NewEncoder(cmd.OutOrStdout())
+			e.SetIndent("", "  ")
+			return e.Encode(v)
+		},
+	}
+
+	// output flag
+	cmd.Flags().String(flagOutputFormat, "toml", "Output format (json|toml)")
+
+	return cmd
+}