bmc: add WaitForSystemPowerState function

pkg/bmc/bmc.go

@@ -586,6 +586,27 @@ func (bmc *BMC) SystemPowerState() (string, error) {
 	return string(system.PowerState), nil
 }
 
+// WaitForSystemPowerState waits up to timeout until the BMC returns the provided system power state.
+func (bmc *BMC) WaitForSystemPowerState(powerState redfish.PowerState, timeout time.Duration) error {
+	if valid, err := bmc.validateRedfish(); !valid {
+		return err
+	}
+
+	glog.V(100).Infof("Waiting up to %s until BMC returns power state %s", timeout, powerState)
+
+	return wait.PollUntilContextTimeout(
+		context.TODO(), 10*time.Second, timeout, true, func(ctx context.Context) (bool, error) {
+			systemPowerState, err := bmc.SystemPowerState()
+			if err != nil {
+				glog.V(100).Infof("Failed to get system power state from BMC: %v", err)
+
+				return false, nil
+			}
+
+			return systemPowerState == string(powerState), nil
+		})
+}
+
 // PowerUsage returns the current power usage of the chassis in watts using the Redfish API. This method uses the first
 // chassis with a power link and the power control index for the BMC client.
 func (bmc *BMC) PowerUsage() (float32, error) {

pkg/bmc/bmc_test.go

@@ -1,6 +1,7 @@
 package bmc
 
 import (
+	"context"
 	_ "embed"
 	"encoding/json"
 	"fmt"
@@ -594,6 +595,22 @@ func TestBMCSystemPowerState(t *testing.T) {
 	assert.Equal(t, expectedPowerState, powerState)
 }
 
+func TestBMCWaitForSystemPowerState(t *testing.T) {
+	// Create fake redfish endpoint.
+	redfishServer := createFakeRedfishLocalServer(false, redfishAPIResponseCallbacks{})
+	defer redfishServer.Close()
+
+	host := strings.Split(redfishServer.URL, "//")[1]
+	bmc := New(host).WithRedfishUser(defaultUsername, defaultPassword)
+
+	// The fake endpoint should be On, so will succeed when waiting till On and time out waiting for Off.
+	err := bmc.WaitForSystemPowerState(redfish.OnPowerState, time.Second)
+	assert.NoError(t, err)
+
+	err = bmc.WaitForSystemPowerState(redfish.OffPowerState, time.Second)
+	assert.Equal(t, context.DeadlineExceeded, err)
+}
+
 func TestBMCPowerUsage(t *testing.T) {
 	// Create a fake redfish api endpoint with secureBoot "disabled"
 	redfishServer := createFakeRedfishLocalServer(false, redfishAPIResponseCallbacks{})