V2 API Version Support

* Update blang/semver to allow ParseTolerant() support
* Provide helper functions for API handlers to obtain client's 'version'
  path variable focused on API endpoint tree: libpod vs. compat
* Introduce new errors:
  * version not given in path, endpoints may determine if this is a hard
    error (ErrVersionNotGiven)
  * given version not supported (ErrVersionNotSupported), only a soft
    error if the handler is going to hijack the connection
* Added unit tests for version parsing
* bindings check version on connect:
  * client <= Server API version connection is continued
  * client >= Server API version connection fails

Signed-off-by: Jhon Honce <jhonce@redhat.com>

1 files changed, 139 insertions, 0 deletions

diff --git a/pkg/api/handlers/utils/handler_test.go b/pkg/api/handlers/utils/handler_test.go
new file mode 100644
index 000000000..6009432b5
--- /dev/null
+++ b/pkg/api/handlers/utils/handler_test.go
@@ -0,0 +1,139 @@
+package utils
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/gorilla/mux"
+)
+
+func TestSupportedVersion(t *testing.T) {
+	req, err := http.NewRequest("GET",
+		fmt.Sprintf("/v%s/libpod/testing/versions", ApiVersion[LibpodTree][CurrentApiVersion]),
+		nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	req = mux.SetURLVars(req, map[string]string{"version": ApiVersion[LibpodTree][CurrentApiVersion].String()})
+
+	rr := httptest.NewRecorder()
+	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, err := SupportedVersionWithDefaults(r)
+		switch {
+		case errors.Is(err, ErrVersionNotGiven): // for compat endpoints version optional
+			w.WriteHeader(http.StatusInternalServerError)
+			fmt.Fprint(w, err.Error())
+		case errors.Is(err, ErrVersionNotSupported): // version given but not supported
+			w.WriteHeader(http.StatusBadRequest)
+			fmt.Fprint(w, err.Error())
+		case err != nil:
+			w.WriteHeader(http.StatusInternalServerError)
+			fmt.Fprint(w, err.Error())
+		default: // all good
+			w.WriteHeader(http.StatusOK)
+			fmt.Fprint(w, "OK")
+		}
+	})
+	handler.ServeHTTP(rr, req)
+
+	if status := rr.Code; status != http.StatusOK {
+		t.Errorf("handler returned wrong status code: got %v want %v",
+			status, http.StatusOK)
+	}
+
+	// Check the response body is what we expect.
+	expected := `OK`
+	if rr.Body.String() != expected {
+		t.Errorf("handler returned unexpected body: got %q want %q",
+			rr.Body.String(), expected)
+	}
+}
+
+func TestUnsupportedVersion(t *testing.T) {
+	version := "999.999.999"
+	req, err := http.NewRequest("GET",
+		fmt.Sprintf("/v%s/libpod/testing/versions", version),
+		nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	req = mux.SetURLVars(req, map[string]string{"version": version})
+
+	rr := httptest.NewRecorder()
+	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, err := SupportedVersionWithDefaults(r)
+		switch {
+		case errors.Is(err, ErrVersionNotGiven): // for compat endpoints version optional
+			w.WriteHeader(http.StatusInternalServerError)
+			fmt.Fprint(w, err.Error())
+		case errors.Is(err, ErrVersionNotSupported): // version given but not supported
+			w.WriteHeader(http.StatusBadRequest)
+			fmt.Fprint(w, err.Error())
+		case err != nil:
+			w.WriteHeader(http.StatusInternalServerError)
+			fmt.Fprint(w, err.Error())
+		default: // all good
+			w.WriteHeader(http.StatusOK)
+			fmt.Fprint(w, "OK")
+		}
+	})
+	handler.ServeHTTP(rr, req)
+
+	if status := rr.Code; status != http.StatusBadRequest {
+		t.Errorf("handler returned wrong status code: got %v want %v",
+			status, http.StatusBadRequest)
+	}
+
+	// Check the response body is what we expect.
+	expected := ErrVersionNotSupported.Error()
+	if rr.Body.String() != expected {
+		t.Errorf("handler returned unexpected body: got %q want %q",
+			rr.Body.String(), expected)
+	}
+}
+
+func TestEqualVersion(t *testing.T) {
+	version := "1.30.0"
+	req, err := http.NewRequest("GET",
+		fmt.Sprintf("/v%s/libpod/testing/versions", version),
+		nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	req = mux.SetURLVars(req, map[string]string{"version": version})
+
+	rr := httptest.NewRecorder()
+	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		_, err := SupportedVersion(r, "=="+version)
+		switch {
+		case errors.Is(err, ErrVersionNotGiven): // for compat endpoints version optional
+			w.WriteHeader(http.StatusInternalServerError)
+			fmt.Fprint(w, err.Error())
+		case errors.Is(err, ErrVersionNotSupported): // version given but not supported
+			w.WriteHeader(http.StatusBadRequest)
+			fmt.Fprint(w, err.Error())
+		case err != nil:
+			w.WriteHeader(http.StatusInternalServerError)
+			fmt.Fprint(w, err.Error())
+		default: // all good
+			w.WriteHeader(http.StatusOK)
+			fmt.Fprint(w, "OK")
+		}
+	})
+	handler.ServeHTTP(rr, req)
+
+	if status := rr.Code; status != http.StatusOK {
+		t.Errorf("handler returned wrong status code: got %v want %v",
+			status, http.StatusOK)
+	}
+
+	// Check the response body is what we expect.
+	expected := http.StatusText(http.StatusOK)
+	if rr.Body.String() != expected {
+		t.Errorf("handler returned unexpected body: got %q want %q",
+			rr.Body.String(), expected)
+	}
+}