feat(deis): only return an APIMismatch when controller is older than SDK (#63)

Author: Joshua-Anderson

http.go

@@ -66,7 +66,7 @@ func (c *Client) Request(method string, path string, body []byte) (*http.Respons
 	c.DeisVersion = res.Header.Get("DEIS_PLATFORM_VERSION")
 
 	// Return results along with api compatibility error
-	return res, checkAPICompatibility(apiVersion)
+	return res, checkAPICompatibility(apiVersion, APIVersion)
 }
 
 // LimitedRequest allows limiting the number of responses in a request.
@@ -129,7 +129,7 @@ your deis version is correct.`
 	apiVersion := res.Header.Get("DEIS_API_VERSION")
 	c.ControllerAPIVersion = apiVersion
 
-	return checkAPICompatibility(apiVersion)
+	return checkAPICompatibility(apiVersion, APIVersion)
 }
 
 func addUserAgent(headers *http.Header, userAgent string) {

utils.go

@@ -1,7 +1,23 @@
 package deis
 
-func checkAPICompatibility(serverAPIVersion string) error {
-	if serverAPIVersion != APIVersion {
+import "strings"
+
+func checkAPICompatibility(serverAPIVersion, clientAPIVersion string) error {
+	sVersion := strings.Split(serverAPIVersion, ".")
+	aVersion := strings.Split(clientAPIVersion, ".")
+
+	// If API Versions are invalid, return a mismatch error.
+	if len(sVersion) < 2 || len(aVersion) < 2 {
+		return ErrAPIMismatch
+	}
+
+	// If major versions are different, return a mismatch error.
+	if sVersion[0] != aVersion[0] {
+		return ErrAPIMismatch
+	}
+
+	// If server is older than client, return mismatch error.
+	if sVersion[1] < aVersion[1] {
 		return ErrAPIMismatch
 	}
 

utils_test.go

@@ -0,0 +1,26 @@
+package deis
+
+import "testing"
+
+type versionComparison struct {
+	Client string
+	Server string
+	Error  error
+}
+
+func TestCheckAPIVersions(t *testing.T) {
+	comparisons := []versionComparison{
+		{"1.2", "2.1", ErrAPIMismatch},
+		{"2.1", "1.2", ErrAPIMismatch},
+		{"2.1", "2.2", ErrAPIMismatch},
+		{"2.3", "2.0", nil},
+	}
+
+	for _, check := range comparisons {
+		err := checkAPICompatibility(check.Client, check.Server)
+
+		if err != check.Error {
+			t.Errorf("%v: Expected %v, Got %v", check, check.Error, err)
+		}
+	}
+}