initial commit

pkg/config/config.go

@@ -0,0 +1,103 @@
+package config
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"net/http"
+	"sync"
+)
+
+type cfg struct {
+	sync.RWMutex
+	m map[string]interface{}
+}
+
+var key struct{}
+
+func New() *cfg {
+	return &cfg{m: make(map[string]interface{})}
+}
+
+func FromContext(ctx context.Context) *cfg {
+	if v, ok := ctx.Value(key).(*cfg); ok {
+		return v
+	}
+
+	return nil
+}
+
+func (c *cfg) Apply(ctx context.Context) context.Context {
+	if inctx := FromContext(ctx); inctx != nil {
+		inctx.setAll(c.m)
+	}
+
+	return context.WithValue(ctx, key, c)
+}
+
+func (c *cfg) setAll(m map[string]interface{}) {
+	if c == nil {
+		return
+	}
+
+	c.Lock()
+	defer c.Unlock()
+
+	c.m = m
+}
+
+func (c *cfg) GetString(name string) string {
+	if v := c.Get(name); v != nil {
+		if s, ok := v.(string); ok {
+			return s
+		} else {
+			return fmt.Sprint(s)
+		}
+	}
+
+	return ""
+}
+
+func (c *cfg) Set(name string, value interface{}) {
+	if c == nil {
+		return
+	}
+
+	c.Lock()
+	defer c.Unlock()
+
+	c.m[name] = value
+}
+
+func (c *cfg) Get(name string) interface{} {
+	if c == nil {
+		return nil
+	}
+
+	c.RLock()
+	defer c.RUnlock()
+
+	return c.m[name]
+}
+
+func (c *cfg) String() string {
+	if c == nil {
+		return "<nil>"
+	}
+
+	c.RLock()
+	defer c.RUnlock()
+
+	var b bytes.Buffer
+	for k, v := range c.m {
+		fmt.Fprintf(&b, "%s = %v\n", k, v)
+	}
+	return b.String()
+}
+
+func (c *cfg) ApplyHTTP(h http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		r = r.WithContext(c.Apply(r.Context()))
+		h.ServeHTTP(w, r)
+	})
+}