feat: add a new .taskrc.yml to enable experiments (#1982)

internal/experiments/experiments.go

@@ -6,13 +6,24 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/Masterminds/semver/v3"
 	"github.com/joho/godotenv"
 	"github.com/spf13/pflag"
+	"gopkg.in/yaml.v3"
 )
 
 const envPrefix = "TASK_X_"
 
-// A set of experiments that can be enabled or disabled.
+var defaultConfigFilenames = []string{
+	".taskrc.yml",
+	".taskrc.yaml",
+}
+
+type experimentConfigFile struct {
+	Experiments map[string]int `yaml:"experiments"`
+	Version     *semver.Version
+}
+
 var (
 	GentleForce     Experiment
 	RemoteTaskfiles Experiment
@@ -22,15 +33,19 @@ var (
 )
 
 // An internal list of all the initialized experiments used for iterating.
-var xList []Experiment
+var (
+	xList            []Experiment
+	experimentConfig experimentConfigFile
+)
 
 func init() {
 	readDotEnv()
-	GentleForce = New("GENTLE_FORCE", "1")
-	RemoteTaskfiles = New("REMOTE_TASKFILES", "1")
+	experimentConfig = readConfig()
+	GentleForce = New("GENTLE_FORCE", 1)
+	RemoteTaskfiles = New("REMOTE_TASKFILES", 1)
 	AnyVariables = New("ANY_VARIABLES")
-	MapVariables = New("MAP_VARIABLES", "1", "2")
-	EnvPrecedence = New("ENV_PRECEDENCE", "1")
+	MapVariables = New("MAP_VARIABLES", 1, 2)
+	EnvPrecedence = New("ENV_PRECEDENCE", 1)
 }
 
 // Validate checks if any experiments have been enabled while being inactive.
@@ -53,7 +68,7 @@ func getEnv(xName string) string {
 	return os.Getenv(envName)
 }
 
-func getEnvFilePath() string {
+func getFilePath(filename string) string {
 	// Parse the CLI flags again to get the directory/taskfile being run
 	// We use a flagset here so that we can parse a subset of flags without exiting on error.
 	var dir, taskfile string
@@ -64,18 +79,18 @@ func getEnvFilePath() string {
 	_ = fs.Parse(os.Args[1:])
 	// If the directory is set, find a .env file in that directory.
 	if dir != "" {
-		return filepath.Join(dir, ".env")
+		return filepath.Join(dir, filename)
 	}
 	// If the taskfile is set, find a .env file in the directory containing the Taskfile.
 	if taskfile != "" {
-		return filepath.Join(filepath.Dir(taskfile), ".env")
+		return filepath.Join(filepath.Dir(taskfile), filename)
 	}
 	// Otherwise just use the current working directory.
-	return ".env"
+	return filename
 }
 
 func readDotEnv() {
-	env, _ := godotenv.Read(getEnvFilePath())
+	env, _ := godotenv.Read(getFilePath(".env"))
 	// If the env var is an experiment, set it.
 	for key, value := range env {
 		if strings.HasPrefix(key, envPrefix) {
@@ -83,3 +98,27 @@ func readDotEnv() {
 		}
 	}
 }
+
+func readConfig() experimentConfigFile {
+	var cfg experimentConfigFile
+
+	var content []byte
+	var err error
+	for _, filename := range defaultConfigFilenames {
+		path := getFilePath(filename)
+		content, err = os.ReadFile(path)
+		if err == nil {
+			break
+		}
+	}
+
+	if err != nil {
+		return experimentConfigFile{}
+	}
+
+	if err := yaml.Unmarshal(content, &cfg); err != nil {
+		return experimentConfigFile{}
+	}
+
+	return cfg
+}