refactor pkg/probe ProbeRunners to interfaces and move global probers into kubelet field for testability

pkg/probe/exec/exec.go

@@ -28,12 +28,16 @@ import (
 const defaultHealthyOutput = "ok"
 
 func New() ExecProber {
-	return ExecProber{}
+	return execProber{}
 }
 
-type ExecProber struct{}
+type ExecProber interface {
+	Probe(e uexec.Cmd) (probe.Result, error)
+}
 
-func (pr ExecProber) Probe(e uexec.Cmd) (probe.Result, error) {
+type execProber struct{}
+
+func (pr execProber) Probe(e uexec.Cmd) (probe.Result, error) {
 	data, err := e.CombinedOutput()
 	glog.V(4).Infof("health check response: %s", string(data))
 	if err != nil {

pkg/probe/http/http.go

@@ -30,15 +30,19 @@ import (
 
 func New() HTTPProber {
 	transport := &http.Transport{}
-	return HTTPProber{transport}
+	return httpProber{transport}
 }
 
-type HTTPProber struct {
+type HTTPProber interface {
+	Probe(host string, port int, path string, timeout time.Duration) (probe.Result, error)
+}
+
+type httpProber struct {
 	transport *http.Transport
 }
 
 // Probe returns a ProbeRunner capable of running an http check.
-func (pr *HTTPProber) Probe(host string, port int, path string, timeout time.Duration) (probe.Result, error) {
+func (pr httpProber) Probe(host string, port int, path string, timeout time.Duration) (probe.Result, error) {
 	return DoHTTPProbe(formatURL(host, port, path), &http.Client{Timeout: timeout, Transport: pr.transport})
 }
 

pkg/probe/tcp/tcp.go

@@ -27,12 +27,16 @@ import (
 )
 
 func New() TCPProber {
-	return TCPProber{}
+	return tcpProber{}
 }
 
-type TCPProber struct{}
+type TCPProber interface {
+	Probe(host string, port int, timeout time.Duration) (probe.Result, error)
+}
 
-func (pr TCPProber) Probe(host string, port int, timeout time.Duration) (probe.Result, error) {
+type tcpProber struct{}
+
+func (pr tcpProber) Probe(host string, port int, timeout time.Duration) (probe.Result, error) {
 	return DoTCPProbe(net.JoinHostPort(host, strconv.Itoa(port)), timeout)
 }