Factor out functionality from update() that will be needed for layering

pkg/daemon/drain.go

@@ -7,7 +7,6 @@ import (
 
 	"github.com/BurntSushi/toml"
 	"github.com/containers/image/v5/pkg/sysregistriesv2"
-	ign3types "github.com/coreos/ignition/v2/config/v3_2/types"
 	"github.com/golang/glog"
 	ctrlcommon "github.com/openshift/machine-config-operator/pkg/controller/common"
 	"github.com/openshift/machine-config-operator/pkg/daemon/constants"
@@ -153,15 +152,17 @@ func (dn *Daemon) performDrain() error {
 	return nil
 }
 
+type ReadFileFunc func(string) ([]byte, error)
+
 // isDrainRequired determines whether node drain is required or not to apply config changes.
-func isDrainRequired(actions, diffFileSet []string, oldIgnConfig, newIgnConfig ign3types.Config) (bool, error) {
+func isDrainRequired(actions, diffFileSet []string, readOldFile, readNewFile ReadFileFunc) (bool, error) {
 	if ctrlcommon.InSlice(postConfigChangeActionReboot, actions) {
 		// Node is going to reboot, we definitely want to perform drain
 		return true, nil
 	} else if ctrlcommon.InSlice(postConfigChangeActionReloadCrio, actions) {
 		// Drain may or may not be necessary in case of container registry config changes.
 		if ctrlcommon.InSlice(constants.ContainerRegistryConfPath, diffFileSet) {
-			isSafe, err := isSafeContainerRegistryConfChanges(oldIgnConfig, newIgnConfig)
+			isSafe, err := isSafeContainerRegistryConfChanges(readOldFile, readNewFile)
 			if err != nil {
 				return false, err
 			}
@@ -175,6 +176,20 @@ func isDrainRequired(actions, diffFileSet []string, oldIgnConfig, newIgnConfig i
 	return true, nil
 }
 
+func (dn *Daemon) drainIfRequired(actions, diffFileSet []string, readOldFile, readNewFile ReadFileFunc) error {
+	drain, err := isDrainRequired(actions, diffFileSet, readOldFile, readNewFile)
+	if err != nil {
+		return err
+	}
+
+	if drain {
+		return dn.performDrain()
+	}
+
+	glog.Info("Changes do not require drain, skipping.")
+	return nil
+}
+
 // isSafeContainerRegistryConfChanges looks inside old and new versions of registries.conf file.
 // It compares the content and determines whether changes made are safe or not. This will
 // help MCD to decide whether we can skip node drain for applied changes into container
@@ -184,16 +199,16 @@ func isDrainRequired(actions, diffFileSet []string, oldIgnConfig, newIgnConfig i
 // 2. A new registry has been added that has `mirror-by-digest-only=true`
 // See https://bugzilla.redhat.com/show_bug.cgi?id=1943315
 //nolint:gocyclo
-func isSafeContainerRegistryConfChanges(oldIgnConfig, newIgnConfig ign3types.Config) (bool, error) {
+func isSafeContainerRegistryConfChanges(readOldFile, readNewFile ReadFileFunc) (bool, error) {
 	// /etc/containers/registries.conf contains config in toml format. Parse the file
-	oldData, err := ctrlcommon.GetIgnitionFileDataByPath(&oldIgnConfig, constants.ContainerRegistryConfPath)
+	oldData, err := readOldFile(constants.ContainerRegistryConfPath)
 	if err != nil {
-		return false, fmt.Errorf("Failed decoding Data URL scheme string: %v", err)
+		return false, fmt.Errorf("failed to get old registries.conf content: %w", err)
 	}
 
-	newData, err := ctrlcommon.GetIgnitionFileDataByPath(&newIgnConfig, constants.ContainerRegistryConfPath)
+	newData, err := readNewFile(constants.ContainerRegistryConfPath)
 	if err != nil {
-		return false, fmt.Errorf("Failed decoding Data URL scheme string %v", err)
+		return false, fmt.Errorf("failed to get new registries.conf content: %w", err)
 	}
 
 	tomlConfOldReg := sysregistriesv2.V2RegistriesConf{}

pkg/daemon/drain_test.go

@@ -359,7 +359,7 @@ location = "example.com/repo/test-img"
 				t.Errorf("parsing new Ignition config failed: %v", err)
 			}
 			diffFileSet := ctrlcommon.CalculateConfigFileDiffs(&oldIgnConfig, &newIgnConfig)
-			drain, err := isDrainRequired(test.actions, diffFileSet, oldIgnConfig, newIgnConfig)
+			drain, err := isDrainRequired(test.actions, diffFileSet, getIgnitionFileDataReadFunc(&oldIgnConfig), getIgnitionFileDataReadFunc(&newIgnConfig))
 			if !reflect.DeepEqual(test.expectedAction, drain) {
 				t.Errorf("Failed determining drain behavior: expected: %v but result is: %v. Error: %v", test.expectedAction, drain, err)
 			}

pkg/daemon/update.go

@@ -116,9 +116,6 @@ func reloadService(name string) error {
 }
 
 // performPostConfigChangeAction takes action based on what postConfigChangeAction has been asked.
-// For non-reboot action, it applies configuration, updates node's config and state.
-// In the end uncordon node to schedule workload.
-// If at any point an error occurs, we reboot the node so that node has correct configuration.
 func (dn *Daemon) performPostConfigChangeAction(postConfigChangeActions []string, configName string) error {
 	if ctrlcommon.InSlice(postConfigChangeActionReboot, postConfigChangeActions) {
 		dn.logSystem("Rebooting node")
@@ -147,10 +144,10 @@ func (dn *Daemon) performPostConfigChangeAction(postConfigChangeActions []string
 		}
 		dn.logSystem("%s config reloaded successfully! Desired config %s has been applied, skipping reboot", serviceName, configName)
 	}
+	return nil
+}
 
-	// We are here, which means reboot was not needed to apply the configuration.
-
-	// Get current state of node, in case of an error reboot
+func (dn *Daemon) getAndUpdateConfigAndState(configName string) error {
 	state, err := dn.getStateAndConfigs(configName)
 	if err != nil {
 		return fmt.Errorf("Could not apply update: error processing state and configs. Error: %v", err)
@@ -484,11 +481,7 @@ func (dn *Daemon) calculatePostConfigChangeActionWithMCDiff(diff *machineConfigD
 	return dn.calculatePostConfigChangeActionFromFiles(diffFileSet)
 }
 
-// update the node to the provided node configuration.
-func (dn *Daemon) update(oldConfig, newConfig *mcfgv1.MachineConfig) (retErr error) {
-
-	oldConfig = canonicalizeEmptyMC(oldConfig)
-
+func (dn *Daemon) setWorking() error {
 	if dn.nodeWriter != nil {
 		state, err := getNodeAnnotationExt(dn.node, constants.MachineConfigDaemonStateAnnotationKey, true)
 		if err != nil {
@@ -500,6 +493,21 @@ func (dn *Daemon) update(oldConfig, newConfig *mcfgv1.MachineConfig) (retErr err
 			}
 		}
 	}
+	return nil
+}
+
+// this should probably become part of the implementation of an Updater interface
+func getIgnitionFileDataReadFunc(ignConfig *ign3types.Config) ReadFileFunc {
+	return func(path string) ([]byte, error) {
+		return ctrlcommon.GetIgnitionFileDataByPath(ignConfig, path)
+	}
+}
+
+// update the node to the provided node configuration.
+func (dn *Daemon) update(oldConfig, newConfig *mcfgv1.MachineConfig) (retErr error) {
+	if err := dn.setWorking(); err != nil {
+		return fmt.Errorf("failed to set working: %w", err)
+	}
 
 	dn.catchIgnoreSIGTERM()
 	defer func() {
@@ -508,6 +516,7 @@ func (dn *Daemon) update(oldConfig, newConfig *mcfgv1.MachineConfig) (retErr err
 		dn.cancelSIGTERM()
 	}()
 
+	oldConfig = canonicalizeEmptyMC(oldConfig)
 	oldConfigName := oldConfig.GetName()
 	newConfigName := newConfig.GetName()
 
@@ -547,17 +556,9 @@ func (dn *Daemon) update(oldConfig, newConfig *mcfgv1.MachineConfig) (retErr err
 	}
 
 	// Check and perform node drain if required
-	drain, err := isDrainRequired(actions, diffFileSet, oldIgnConfig, newIgnConfig)
-	if err != nil {
+	if err := dn.drainIfRequired(actions, diffFileSet, getIgnitionFileDataReadFunc(&oldIgnConfig), getIgnitionFileDataReadFunc(&newIgnConfig)); err != nil {
 		return err
 	}
-	if drain {
-		if err := dn.performDrain(); err != nil {
-			return err
-		}
-	} else {
-		glog.Info("Changes do not require drain, skipping.")
-	}
 
 	// update files on disk that need updating
 	if err := dn.updateFiles(oldIgnConfig, newIgnConfig); err != nil {
@@ -626,7 +627,16 @@ func (dn *Daemon) update(oldConfig, newConfig *mcfgv1.MachineConfig) (retErr err
 		return err
 	}
 
-	return dn.performPostConfigChangeAction(actions, newConfig.GetName())
+	if err := dn.performPostConfigChangeAction(actions, newConfig.GetName()); err != nil {
+		return err
+	}
+
+	// if dn.skipReboot, a reboot might be performed manually after update(), in which case we don't want to update state
+	// else reboot was not needed to apply the configuration, and we need to update state
+	if !dn.skipReboot {
+		return dn.getAndUpdateConfigAndState(newConfig.GetName())
+	}
+	return nil
 }
 
 // machineConfigDiff represents an ad-hoc difference between two MachineConfig objects.