feat: refactor some config init logic into config package

Signed-off-by: Brian McGee <brian@bmcgee.ie>

cli/format.go

@@ -9,8 +9,6 @@ import (
 	"os/signal"
 	"path/filepath"
 	"runtime"
-	"slices"
-	"sort"
 	"strings"
 	"syscall"
 
@@ -41,57 +39,32 @@ var (
 )
 
 func (f *Format) Run() (err error) {
-	stats.Init()
-
+	// create a prefixed logger
 	l := log.WithPrefix("format")
 
+	// ensure cache is closed on return
 	defer func() {
 		if err := cache.Close(); err != nil {
 			l.Errorf("failed to close cache: %v", err)
 		}
 	}()
 
 	// read config
-	cfg, err := config.ReadFile(Cli.ConfigFile)
+	cfg, err := config.ReadFile(Cli.ConfigFile, Cli.Formatters)
 	if err != nil {
 		return fmt.Errorf("%w: failed to read config file", err)
 	}
 
+	// compile global exclude globs
 	if globalExcludes, err = format.CompileGlobs(cfg.Global.Excludes); err != nil {
 		return fmt.Errorf("%w: failed to compile global globs", err)
 	}
 
+	// initialise pipelines
 	pipelines = make(map[string]*format.Pipeline)
 	formatters = make(map[string]*format.Formatter)
 
-	// filter formatters
-	if len(Cli.Formatters) > 0 {
-		// first check the cli formatter list is valid
-		for _, name := range Cli.Formatters {
-			_, ok := cfg.Formatters[name]
-			if !ok {
-				return fmt.Errorf("formatter not found in config: %v", name)
-			}
-		}
-		// next we remove any formatter configs that were not specified
-		for name := range cfg.Formatters {
-			if !slices.Contains(Cli.Formatters, name) {
-				delete(cfg.Formatters, name)
-			}
-		}
-	}
-
-	// sort the formatter names so that, as we construct pipelines, we add formatters in a determinstic fashion. This
-	// ensures a deterministic order even when all priority values are the same e.g. 0
-
-	names := make([]string, 0, len(cfg.Formatters))
-	for name := range cfg.Formatters {
-		names = append(names, name)
-	}
-	sort.Strings(names)
-
-	// init formatters
-	for _, name := range names {
+	for _, name := range cfg.Names {
 		formatterCfg := cfg.Formatters[name]
 		formatter, err := format.NewFormatter(name, Cli.TreeRoot, formatterCfg, globalExcludes)
 		if errors.Is(err, format.ErrCommandNotFound) && Cli.AllowMissingFormatter {
@@ -134,6 +107,9 @@ func (f *Format) Run() (err error) {
 		cancel()
 	}()
 
+	// initialise stats collection
+	stats.Init()
+
 	// create some groups for concurrent processing and control flow
 	eg, ctx := errgroup.WithContext(ctx)
 

config/config.go

@@ -1,18 +1,51 @@
 package config
 
-import "github.com/BurntSushi/toml"
+import (
+	"fmt"
+	"sort"
+
+	"github.com/BurntSushi/toml"
+)
 
 // Config is used to represent the list of configured Formatters.
 type Config struct {
 	Global struct {
 		// Excludes is an optional list of glob patterns used to exclude certain files from all formatters.
 		Excludes []string
 	}
+	Names      []string              `toml:"-"`
 	Formatters map[string]*Formatter `toml:"formatter"`
 }
 
 // ReadFile reads from path and unmarshals toml into a Config instance.
-func ReadFile(path string) (cfg *Config, err error) {
-	_, err = toml.DecodeFile(path, &cfg)
+func ReadFile(path string, names []string) (cfg *Config, err error) {
+	if _, err = toml.DecodeFile(path, &cfg); err != nil {
+		return nil, fmt.Errorf("failed to decode config file: %w", err)
+	}
+
+	// filter formatters based on provided names
+	if len(names) > 0 {
+		filtered := make(map[string]*Formatter)
+
+		// check if the provided names exist in the config
+		for _, name := range names {
+			formatterCfg, ok := cfg.Formatters[name]
+			if !ok {
+				return nil, fmt.Errorf("formatter %v not found in config", name)
+			}
+			filtered[name] = formatterCfg
+		}
+
+		// updated formatters
+		cfg.Formatters = filtered
+	}
+
+	// sort the formatter names so that, as we construct pipelines, we add formatters in a determinstic fashion. This
+	// ensures a deterministic order even when all priority values are the same e.g. 0
+	for name := range cfg.Formatters {
+		cfg.Names = append(cfg.Names, name)
+	}
+	sort.Strings(cfg.Names)
+
 	return
 }

config/config_test.go

@@ -9,7 +9,7 @@ import (
 func TestReadConfigFile(t *testing.T) {
 	as := require.New(t)
 
-	cfg, err := ReadFile("../test/examples/treefmt.toml")
+	cfg, err := ReadFile("../test/examples/treefmt.toml", nil)
 	as.NoError(err, "failed to read config file")
 
 	as.NotNil(cfg)

format/formatter.go

@@ -111,7 +111,7 @@ func (f *Formatter) Wants(file *walk.File) bool {
 func NewFormatter(
 	name string,
 	treeRoot string,
-	config *config.Formatter,
+	cfg *config.Formatter,
 	globalExcludes []glob.Glob,
 ) (*Formatter, error) {
 	var err error
@@ -120,11 +120,11 @@ func NewFormatter(
 
 	// capture config and the formatter's name
 	f.name = name
-	f.config = config
+	f.config = cfg
 	f.workingDir = treeRoot
 
 	// test if the formatter is available
-	executable, err := exec.LookPath(config.Command)
+	executable, err := exec.LookPath(cfg.Command)
 	if errors.Is(err, exec.ErrNotFound) {
 		return nil, ErrCommandNotFound
 	} else if err != nil {
@@ -133,18 +133,18 @@ func NewFormatter(
 	f.executable = executable
 
 	// initialise internal state
-	if config.Pipeline == "" {
+	if cfg.Pipeline == "" {
 		f.log = log.WithPrefix(fmt.Sprintf("format | %s", name))
 	} else {
-		f.log = log.WithPrefix(fmt.Sprintf("format | %s[%s]", config.Pipeline, name))
+		f.log = log.WithPrefix(fmt.Sprintf("format | %s[%s]", cfg.Pipeline, name))
 	}
 
-	f.includes, err = CompileGlobs(config.Includes)
+	f.includes, err = CompileGlobs(cfg.Includes)
 	if err != nil {
 		return nil, fmt.Errorf("%w: formatter '%v' includes", err, f.name)
 	}
 
-	f.excludes, err = CompileGlobs(config.Excludes)
+	f.excludes, err = CompileGlobs(cfg.Excludes)
 	if err != nil {
 		return nil, fmt.Errorf("%w: formatter '%v' excludes", err, f.name)
 	}