Don't use go-dockerclient to en/decode inspects in the proxy

proxy/json.go

@@ -0,0 +1,46 @@
+package proxy
+
+import (
+	"fmt"
+)
+
+type UnmarshalWrongTypeError struct {
+	Field, Expected string
+	Got             interface{}
+}
+
+func (e *UnmarshalWrongTypeError) Error() string {
+	return fmt.Sprintf("Wrong type for %s field, expected %s, but got %T", e.Field, e.Expected, e.Got)
+}
+
+// For parsing json objects. Look up (or create) a child object in the given map.
+func lookupObject(m map[string]interface{}, key string) (map[string]interface{}, error) {
+	iface, ok := m[key]
+	if !ok || iface == nil {
+		result := map[string]interface{}{}
+		m[key] = result
+		return result, nil
+	}
+
+	result, ok := iface.(map[string]interface{})
+	if !ok {
+		return nil, &UnmarshalWrongTypeError{key, "object", iface}
+	}
+
+	return result, nil
+}
+
+// For parsing json objects. Look up (or create) a string in the given map.
+func lookupString(m map[string]interface{}, key string) (string, error) {
+	iface, ok := m[key]
+	if !ok || iface == nil {
+		return "", nil
+	}
+
+	result, ok := iface.(string)
+	if !ok {
+		return "", &UnmarshalWrongTypeError{key, "string", iface}
+	}
+
+	return result, nil
+}