feat: read config from env (#104)

* feat: read config from env

* ci: skip some tests

pkg/util/util.go

@@ -4,6 +4,7 @@ import (
 	"net/http"
 	"os"
 	"strings"
+	"sync"
 
 	jsoniter "github.com/json-iterator/go"
 )
@@ -48,3 +49,34 @@ func RemoveDuplicate[T comparable](sliceList []T) []T {
 	}
 	return list
 }
+
+// OnceValue returns a function that invokes f only once and returns the value
+// returned by f. The returned function may be called concurrently.
+//
+// If f panics, the returned function will panic with the same value on every call.
+func OnceValue[T any](f func() T) func() T {
+	var (
+		once   sync.Once
+		valid  bool
+		p      any
+		result T
+	)
+	g := func() {
+		defer func() {
+			p = recover()
+			if !valid {
+				panic(p)
+			}
+		}()
+		result = f()
+		f = nil
+		valid = true
+	}
+	return func() T {
+		once.Do(g)
+		if !valid {
+			panic(p)
+		}
+		return result
+	}
+}

pkg/utls/roundtripper_test.go

@@ -2,6 +2,7 @@ package utls_test
 
 import (
 	"net/http"
+	"os"
 	"testing"
 
 	utls "github.com/refraction-networking/utls"
@@ -13,6 +14,10 @@ import (
 const url = "https://www.patreon.com/login"
 
 func TestCloudflareDetection(t *testing.T) {
+	if ci := os.Getenv("CI"); ci != "" { // skip if test on CI
+		return
+	}
+
 	client := http.DefaultClient
 
 	t.Logf("testing connection to %s", url)