Update influx package to support MonitoredServices

The Timeseries interface was updated to include MonitoredServices as
part of its spec. This adds a stub implementation of that.

influx/influx.go

@@ -12,7 +12,9 @@ type Client struct {
 	ix ixClient.Client
 }
 
-// NewClient initializes a Client
+// NewClient initializes an HTTP Client for InfluxDB. UDP, although supported
+// for querying InfluxDB, is not supported here to remove the need to
+// explicitly Close the client.
 func NewClient(host string) (*Client, error) {
 	cl, err := ixClient.NewHTTPClient(ixClient.HTTPConfig{
 		Addr: host,
@@ -46,3 +48,9 @@ func (c *Client) Query(ctx context.Context, query mrfusion.Query) (mrfusion.Resp
 		return nil, TimeoutError{}
 	}
 }
+
+// MonitoredServices returns all services for which this instance of InfluxDB
+// has time series information stored for.
+func (c *Client) MonitoredServices(ctx context.Context) ([]mrfusion.MonitoredService, error) {
+	return []mrfusion.MonitoredService{}, nil
+}

mock/mock.go

@@ -121,6 +121,10 @@ type Response struct {
 	results []mrfusion.Result
 }
 
+func (r *Response) MarshalJSON() ([]byte, error) {
+	return []byte(`{}`), nil
+}
+
 var SampleResponse mrfusion.Response = NewResponse(SampleResult)
 
 func NewResponse(result mrfusion.Result) mrfusion.Response {