Merge pull request #30 from digitalocean/mdl-ovsb-params-interface

ovsdb: make params an interface for more type flexibility

Author: mdlayher

ovsdb/client.go

@@ -200,7 +200,7 @@ type ClientStats struct {
 }
 
 // rpc performs a single RPC request, and checks the response for errors.
-func (c *Client) rpc(ctx context.Context, method string, out interface{}, args ...interface{}) error {
+func (c *Client) rpc(ctx context.Context, method string, out, arg interface{}) error {
 	// Was the context canceled before sending the RPC?
 	select {
 	case <-ctx.Done():
@@ -218,7 +218,7 @@ func (c *Client) rpc(ctx context.Context, method string, out interface{}, args .
 
 	req := jsonrpc.Request{
 		Method: method,
-		Params: args,
+		Params: arg,
 		ID:     c.requestID(),
 	}
 

ovsdb/internal/jsonrpc/conn.go

@@ -25,9 +25,9 @@ import (
 
 // A Request is a JSON-RPC request.
 type Request struct {
-	ID     string        `json:"id"`
-	Method string        `json:"method"`
-	Params []interface{} `json:"params"`
+	ID     string      `json:"id"`
+	Method string      `json:"method"`
+	Params interface{} `json:"params"`
 }
 
 // A Response is either a JSON-RPC response, or a JSON-RPC request notification.

ovsdb/rpc.go

@@ -22,7 +22,7 @@ import (
 // ListDatabases returns the name of all databases known to the OVSDB server.
 func (c *Client) ListDatabases(ctx context.Context) ([]string, error) {
 	var dbs []string
-	if err := c.rpc(ctx, "list_dbs", &dbs); err != nil {
+	if err := c.rpc(ctx, "list_dbs", &dbs, nil); err != nil {
 		return nil, err
 	}
 
@@ -32,14 +32,14 @@ func (c *Client) ListDatabases(ctx context.Context) ([]string, error) {
 // Echo verifies that the OVSDB connection is alive, and can be used to keep
 // the connection alive.
 func (c *Client) Echo(ctx context.Context) error {
-	const req = "github.com/digitalocean/go-openvswitch/ovsdb"
+	req := [1]string{"github.com/digitalocean/go-openvswitch/ovsdb"}
 
 	var res [1]string
 	if err := c.rpc(ctx, "echo", &res, req); err != nil {
 		return err
 	}
 
-	if res[0] != req {
+	if res[0] != req[0] {
 		return fmt.Errorf("invalid echo response: %q", res[0])
 	}
 

ovsdb/rpc_test.go

@@ -30,7 +30,10 @@ func TestClientListDatabases(t *testing.T) {
 			panicf("unexpected RPC method (-want +got):\n%s", diff)
 		}
 
-		if diff := cmp.Diff(0, len(req.Params)); diff != "" {
+		// Client should send an empty array parameter.
+		ps := req.Params.([]interface{})
+
+		if diff := cmp.Diff(0, len(ps)); diff != "" {
 			panicf("unexpected number of RPC parameters (-want +got):\n%s", diff)
 		}