move file writes to a helper

nodeadm/internal/containerd/config.go

@@ -4,8 +4,6 @@ import (
 	"bytes"
 	"context"
 	_ "embed"
-	"os"
-	"path"
 	"text/template"
 
 	"github.com/aws/aws-sdk-go-v2/feature/ec2/imds"
@@ -33,10 +31,7 @@ func writeContainerdConfig(cfg *api.NodeConfig) error {
 	if err != nil {
 		return err
 	}
-	if err := os.MkdirAll(path.Dir(containerdConfigFile), containerdConfigPerm); err != nil {
-		return err
-	}
-	return os.WriteFile(containerdConfigFile, containerdConfig, containerdConfigPerm)
+	return util.WriteFileWithDir(containerdConfigFile, containerdConfig, containerdConfigPerm)
 }
 
 func generateContainerdConfig(cfg *api.NodeConfig) ([]byte, error) {

nodeadm/internal/daemon/systemd.go

@@ -6,9 +6,9 @@ import (
 	"context"
 	"fmt"
 	"io/fs"
-	"os"
 	"path"
 
+	"github.com/awslabs/amazon-eks-ami/nodeadm/internal/util"
 	"github.com/coreos/go-systemd/dbus"
 )
 
@@ -114,13 +114,10 @@ const servicesRoot = "/etc/systemd/system"
 
 func WriteSystemdServiceUnitDropIn(serviceName, fileName, fileContent string, filePerms fs.FileMode) error {
 	dropInPath := path.Join(servicesRoot, getServiceUnitDropInDir(serviceName), fileName)
-	if err := os.MkdirAll(path.Dir(dropInPath), filePerms); err != nil {
-		return err
-	}
-	return os.WriteFile(dropInPath, []byte(fileContent), filePerms)
+	return util.WriteFileWithDir(dropInPath, []byte(fileContent), filePerms)
 }
 
 func WriteSystemdServiceUnit(serviceName, unitContent string, filePerms fs.FileMode) error {
 	serviceUnitPath := path.Join(servicesRoot, getServiceUnitName(serviceName))
-	return os.WriteFile(serviceUnitPath, []byte(unitContent), filePerms)
+	return util.WriteFileWithDir(serviceUnitPath, []byte(unitContent), filePerms)
 }

nodeadm/internal/kubelet/cert.go

@@ -1,17 +1,13 @@
 package kubelet
 
 import (
-	"os"
-	"path"
+	"github.com/awslabs/amazon-eks-ami/nodeadm/internal/util"
 )
 
 const caCertificatePath = "/etc/kubernetes/pki/ca.crt"
 
 // Write the cluster certifcate authority to the filesystem where
 // both kubelet and kubeconfig can read it
 func writeClusterCaCert(caCert []byte) error {
-	if err := os.MkdirAll(path.Dir(caCertificatePath), kubeletConfigPerm); err != nil {
-		return err
-	}
-	return os.WriteFile(caCertificatePath, caCert, kubeletConfigPerm)
+	return util.WriteFileWithDir(caCertificatePath, caCert, kubeletConfigPerm)
 }

nodeadm/internal/kubelet/config.go

@@ -25,6 +25,7 @@ import (
 
 	"github.com/awslabs/amazon-eks-ami/nodeadm/internal/api"
 	featuregates "github.com/awslabs/amazon-eks-ami/nodeadm/internal/feature-gates"
+	"github.com/awslabs/amazon-eks-ami/nodeadm/internal/util"
 )
 
 const (
@@ -284,33 +285,25 @@ func (k *kubelet) GenerateKubeletConfig(cfg *api.NodeConfig) (*kubeletSubConfig,
 //   - kubeletConfigOverrides should be passed in the order of application
 func (k *kubelet) writeKubeletConfigToFile(kubeletConfig []byte) error {
 	configPath := path.Join(kubeletConfigRoot, kubeletConfigFile)
-	if err := os.MkdirAll(path.Dir(configPath), kubeletConfigPerm); err != nil {
-		return err
-	}
-
 	k.additionalArguments["config"] = configPath
 
 	zap.L().Info("Writing kubelet config to file..", zap.String("path", configPath))
-	return os.WriteFile(configPath, kubeletConfig, kubeletConfigPerm)
+	return util.WriteFileWithDir(configPath, kubeletConfig, kubeletConfigPerm)
 }
 
 // WriteKubeletConfigToDir writes the kubelet config to a directory for drop-in
 // directory support. This is only supported on kubelet versions >= 1.28.
 // see: https://kubernetes.io/docs/tasks/administer-cluster/kubelet-config-file/#kubelet-conf-d
 func (k *kubelet) writeKubeletConfigToDir(kubeletConfig []byte) error {
 	dirPath := path.Join(kubeletConfigRoot, kubeletConfigDir)
-	if err := os.MkdirAll(dirPath, kubeletConfigPerm); err != nil {
-		return err
-	}
-
 	k.additionalArguments["config-dir"] = dirPath
 
 	zap.L().Info("Enabling kubelet config drop-in dir..")
 	k.setEnv("KUBELET_CONFIG_DROPIN_DIR_ALPHA", "on")
 
 	filePath := path.Join(dirPath, "10-defaults.conf")
 	zap.L().Info("Writing kubelet config to drop-in file..", zap.String("path", filePath))
-	return os.WriteFile(filePath, kubeletConfig, kubeletConfigPerm)
+	return util.WriteFileWithDir(filePath, kubeletConfig, kubeletConfigPerm)
 }
 
 func getProviderId(availabilityZone, instanceId string) string {

nodeadm/internal/kubelet/image-credential-provider.go

@@ -10,6 +10,7 @@ import (
 	"text/template"
 
 	"github.com/awslabs/amazon-eks-ami/nodeadm/internal/api"
+	"github.com/awslabs/amazon-eks-ami/nodeadm/internal/util"
 	"go.uber.org/zap"
 	"golang.org/x/mod/semver"
 )
@@ -48,10 +49,7 @@ func (k *kubelet) writeImageCredentialProviderConfig(cfg *api.NodeConfig) error
 	k.additionalArguments["image-credential-provider-bin-dir"] = path.Dir(ecrCredentialProviderBinPath)
 	k.additionalArguments["image-credential-provider-config"] = imageCredentialProviderConfigPath
 
-	if err := os.MkdirAll(imageCredentialProviderRoot, imageCredentialProviderPerm); err != nil {
-		return err
-	}
-	return os.WriteFile(imageCredentialProviderConfigPath, config, imageCredentialProviderPerm)
+	return util.WriteFileWithDir(imageCredentialProviderConfigPath, config, imageCredentialProviderPerm)
 }
 
 type imageCredentialProviderTemplateVars struct {

nodeadm/internal/kubelet/kubeconfig.go

@@ -3,11 +3,11 @@ package kubelet
 import (
 	"bytes"
 	_ "embed"
-	"os"
 	"path"
 	"text/template"
 
 	"github.com/awslabs/amazon-eks-ami/nodeadm/internal/api"
+	"github.com/awslabs/amazon-eks-ami/nodeadm/internal/util"
 )
 
 const (
@@ -30,18 +30,15 @@ func (k *kubelet) writeKubeconfig(cfg *api.NodeConfig) error {
 	if err != nil {
 		return err
 	}
-	if err := os.MkdirAll(kubeconfigRoot, kubeconfigPerm); err != nil {
-		return err
-	}
 	if enabled := cfg.Spec.Cluster.EnableOutpost; enabled != nil && *enabled {
 		// kubelet bootstrap kubeconfig uses aws-iam-authenticator with cluster id to authenticate to cluster
 		//   - if "aws eks describe-cluster" is bypassed, for local outpost, the value of CLUSTER_NAME parameter will be cluster id.
 		//   - otherwise, the cluster id will use the id returned by "aws eks describe-cluster".
 		k.additionalArguments["bootstrap-kubeconfig"] = kubeconfigBootstrapPath
-		return os.WriteFile(kubeconfigBootstrapPath, kubeconfig, kubeconfigPerm)
+		return util.WriteFileWithDir(kubeconfigBootstrapPath, kubeconfig, kubeconfigPerm)
 	} else {
 		k.additionalArguments["kubeconfig"] = kubeconfigPath
-		return os.WriteFile(kubeconfigPath, kubeconfig, kubeconfigPerm)
+		return util.WriteFileWithDir(kubeconfigPath, kubeconfig, kubeconfigPerm)
 	}
 }
 

nodeadm/internal/util/sys.go

@@ -2,14 +2,25 @@ package util
 
 import (
 	"errors"
+	"io/fs"
 	"os"
 	"os/exec"
+	"path"
 	"strconv"
 	"strings"
 )
 
 const trimChars = " \n\t"
 
+// Wraps os.WriteFile to automatically create parent directories such that the
+// caller does not need to ensure the existence of the file's directory
+func WriteFileWithDir(filePath string, data []byte, perm fs.FileMode) error {
+	if err := os.MkdirAll(path.Dir(filePath), perm); err != nil {
+		return err
+	}
+	return os.WriteFile(filePath, data, perm)
+}
+
 func isHostPresent(host string) (bool, error) {
 	output, err := exec.Command("getent", "hosts", host).Output()
 	if err != nil {