### Install Objx

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/stretchr/objx/README.md

Install the Objx package using the go get command.

```bash
go get github.com/stretchr/objx
```

--------------------------------

### Install Mergo

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/dario.cat/mergo/README.md

Install the Mergo library using go get.

```go
go get dario.cat/mergo
```

--------------------------------

### Install Cobra Library

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/spf13/cobra/README.md

Use 'go get' to install the latest version of the Cobra library.

```go
go get -u github.com/spf13/cobra@latest
```

--------------------------------

### Install multierr

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/go.uber.org/multierr/README.md

Use 'go get' to install the latest version of the multierr package.

```bash
go get -u go.uber.org/multierr@latest
```

--------------------------------

### Install Flaggy Go Library

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/integrii/flaggy/README.md

Use 'go get' to install the Flaggy library. This command fetches and installs the latest version of the package.

```bash
go get -u github.com/integrii/flaggy
```

--------------------------------

### Install go.yaml.in/yaml/v3

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/go.yaml.in/yaml/v3/README.md

Use 'go get' to install the latest version of the YAML package for Go.

```bash
go get go.yaml.in/yaml/v3
```

--------------------------------

### Super Simple Flaggy Example

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/integrii/flaggy/README.md

Demonstrates the basic usage of Flaggy by declaring a string flag, parsing it, and then printing its value. This is a good starting point for understanding Flaggy's core functionality.

```go
// Declare variables and their defaults
var stringFlag = "defaultValue"

// Add a flag
flaggy.String(&stringFlag, "f", "flag", "A test string flag")

// Parse the flag
flaggy.Parse()

// Use the flag
print(stringFlag)
```

--------------------------------

### Install json-iterator/go

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/json-iterator/go/README.md

Use the go get command to install the json-iterator/go package into your project.

```bash
go get github.com/json-iterator/go
```

--------------------------------

### Install godbus/dbus

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/godbus/dbus/v5/README.md

Install the library using the go get command. Requires Go 1.12 or later.

```bash
go get github.com/godbus/dbus/v5
```

--------------------------------

### Install YAML Package for Go

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/gopkg.in/yaml.v3/README.md

Use `go get` to install the `gopkg.in/yaml.v3` package. This command fetches and installs the specified package and its dependencies.

```Go
go get gopkg.in/yaml.v3
```

--------------------------------

### Example Output for Latest Binaries

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/doc/usage/overview.md

This is an example of the output from the `hack/latest-binaries.sh` script, showing the resolved Kubernetes version and build date.

```bash
> hack/latest-binaries.sh 1.28 us-west-2

kubernetes_version=1.28.1 kubernetes_build_date=2023-10-01
```

--------------------------------

### Basic Flaggy Setup and Usage in Go

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/integrii/flaggy/README.md

Demonstrates setting program name, description, and parsing flags. Use this for initializing your command-line application with flaggy.

```go
package main

import "github.com/integrii/flaggy"

// Make a variable for the version which will be set at build time.
var version = "unknown"

// Keep subcommands as globals so you can easily check if they were used later on.
var mySubcommand *flaggy.Subcommand

// Setup the variables you want your incoming flags to set.
var testVar string

// If you would like an environment variable as the default for a value, just populate the flag
// with the value of the environment by default.  If the flag corresponding to this value is not
// used, then it will not be changed.
var myVar = os.Getenv("MY_VAR")


func init() {
  // Set your program's name and description.  These appear in help output.
  flaggy.SetName("Test Program")
  flaggy.SetDescription("A little example program")

  // You can disable various things by changing bools on the default parser
  // (or your own parser if you have created one).
  flaggy.DefaultParser.ShowHelpOnUnexpected = false

  // You can set a help prepend or append on the default parser.
  flaggy.DefaultParser.AdditionalHelpPrepend = "http://github.com/integrii/flaggy"
  
  // Add a flag to the main program (this will be available in all subcommands as well).
  flaggy.String(&testVar, "tv", "testVariable", "A variable just for testing things!")

  // Create any subcommands and set their parameters.
  mySubcommand = flaggy.NewSubcommand("mySubcommand")
  mySubcommand.Description = "My great subcommand!"
  
  // Add a flag to the subcommand.
  mySubcommand.String(&myVar, "mv", "myVariable", "A variable just for me!")

  // Set the version and parse all inputs into variables.
  flaggy.SetVersion(version)
  flaggy.Parse()
}

func main(){
    if mySubcommand.Used {
      ...
    }
}

```

--------------------------------

### Setup Zap Repository

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/go.uber.org/zap/CONTRIBUTING.md

Clone the zap repository and set up the upstream remote for contributing. Ensure your GOPATH is correctly configured.

```bash
mkdir -p $GOPATH/src/go.uber.org
cd $GOPATH/src/go.uber.org
git clone git@github.com:your_github_username/zap.git
cd zap
git remote add upstream https://github.com/uber-go/zap.git
git fetch upstream
```

--------------------------------

### Initialize Procfs and Get Stat

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/prometheus/procfs/README.md

Initialize the proc filesystem mount point and read CPU statistics. Use this to get general system CPU metrics.

```go
fs, err := procfs.NewFS("/proc")
stats, err := fs.Stat()
```

--------------------------------

### Example of Commented TOML Configuration

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/pelletier/go-toml/v2/README.md

Demonstrates how go-toml can generate TOML documents with comments and commented-out values, useful for configuration files.

```toml
# Host IP to connect to.
host = '127.0.0.1'
# Port of the remote server.
port = 4242

# Encryption parameters (optional)
# [TLS]
# cipher = 'AEAD-AES128-GCM-SHA256'
# version = 'TLS 1.3'
```

--------------------------------

### Install jsontoml CLI Tool

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/pelletier/go-toml/v2/README.md

Installs the jsontoml command-line tool. Use this to convert JSON files to TOML.

```bash
$ go install github.com/pelletier/go-toml/v2/cmd/jsontoml@latest
$ jsontoml --help
```

--------------------------------

### Install Cobra CLI Generator

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/spf13/cobra/README.md

Install the cobra-cli tool for generating Cobra application scaffolding.

```go
go install github.com/spf13/cobra-cli@latest
```

--------------------------------

### Coexisting with klog/v1 and klog/v2

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/k8s.io/klog/v2/README.md

Provides an example of how to manage the coexistence of both klog/v1 and klog/v2 within the same project.

```go
// See examples/coexist_klog_v1_and_v2/
```

--------------------------------

### Install tomll CLI Tool

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/pelletier/go-toml/v2/README.md

Installs the tomll command-line tool. Use this to lint and reformat TOML files.

```bash
$ go install github.com/pelletier/go-toml/v2/cmd/tomll@latest
$ tomll --help
```

--------------------------------

### Install tomljson CLI Tool

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/pelletier/go-toml/v2/README.md

Installs the tomljson command-line tool. Use this to convert TOML files to JSON.

```bash
$ go install github.com/pelletier/go-toml/v2/cmd/tomljson@latest
$ tomljson --help
```

--------------------------------

### Install Specific golangci-lint Version

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/pelletier/go-toml/v2/AGENTS.md

Install a specific version of golangci-lint using a provided script. Ensure the version matches the one used in the CI configuration.

```bash
# Install specific version (check lint.yml for current version)
curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/HEAD/install.sh | sh -s -- -b $(go env GOPATH)/bin <version>
```

--------------------------------

### Import go-toml/v2 Library

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/pelletier/go-toml/v2/README.md

Import the go-toml/v2 library to start using its functionalities.

```go
import "github.com/pelletier/go-toml/v2"
```

--------------------------------

### Create Root Logger

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/go-logr/logr/README.md

Initialize the root logger early in an application's lifecycle. This example shows creating a logger using a hypothetical 'logimpl' implementation with initial parameters.

```go
func main() {
    // ... other setup code ...

    // Create the "root" logger.  We have chosen the "logimpl" implementation,
    // which takes some initial parameters and returns a logr.Logger.
    logger := logimpl.New(param1, param2)

    // ... other setup code ...
}
```

--------------------------------

### Add or Update Dependencies

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/prometheus/procfs/CONTRIBUTING.md

Use `go get` to fetch specific versions of external packages. Ensure your Go environment meets version requirements.

```bash
# Pick the latest tagged release.
go get example.com/some/module/pkg

# Pick a specific version.
go get example.com/some/module/pkg@vX.Y.Z
```

--------------------------------

### Go Client Code Generation Configuration

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/aws/smithy-go/README.md

Example smithy-build.json configuration for enabling the `go-codegen` plugin. Specifies the service, module, and Go version for client generation.

```json
{
  "version": "1.0",
  "sources": [
    "models"
  ],
  "maven": {
    "dependencies": [
      "software.amazon.smithy.go:smithy-go-codegen:0.1.0"
    ]
  },
  "plugins": {
    "go-codegen": {
      "service": "example.weather#Weather",
      "module": "github.com/example/weather",
      "generateGoMod": true,
      "goDirective": "1.24"
    }
  }
}
```

--------------------------------

### Example using TagSet and TagOptions

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/fxamacker/cbor/v2/README.md

Shows how to create a TagSet, register custom types with specific CBOR tags, and then use these tags with DecMode and EncMode for unmarshalling and marshalling data.

```go
// Use signedCWT struct defined in "Decoding CWT" example.

// Create TagSet (safe for concurrency).
tags := cbor.NewTagSet()
// Register tag COSE_Sign1 18 with signedCWT type.
tags.Add(	
cbor.TagOptions{EncTag: cbor.EncTagRequired, DecTag: cbor.DecTagRequired},
	reflect.TypeOf(signedCWT{}),
	18)

// Create DecMode with immutable tags.
dm, _ := cbor.DecOptions{}.DecModeWithTags(tags)

// Unmarshal to signedCWT with tag support.
var v signedCWT
if err := dm.Unmarshal(data, &v); err != nil {
	return err
}

// Create EncMode with immutable tags.
em, _ := cbor.EncOptions{}.EncModeWithTags(tags)

// Marshal signedCWT with tag number.
if data, err := em.Marshal(v); err != nil {
	return err
}
```

--------------------------------

### go-toml v1 Interface Decoding Example

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/pelletier/go-toml/v2/README.md

Demonstrates how go-toml v1 uses the existing type within an interface to decode TOML data.

```go
package main

import (
	"fmt"
	"toml"
)

type inner struct {
	B interface{}
}
type doc struct {
	A interface{}
}

func main() {
	d := doc{
		A: inner{
			B: "Before",
		},
	}

	data := `
[A]
B = "After"
`

	toml.Unmarshal([]byte(data), &d)
	fmt.Printf("toml v1: %#v\n", d)

	// toml v1: main.doc{A:main.inner{B:"After"}}
}
```

--------------------------------

### Development Panic Example

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/go.uber.org/zap/FAQ.md

Use DPanic to catch errors that should not occur in development without crashing production. This example shows how to replace a panic with DPanic.

```go
if err != nil {
  panic(fmt.Sprintf("shouldn't ever get here: %v", err))
}
```

--------------------------------

### Zap Logger Quick Start

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/go.uber.org/zap/README.md

Use the Logger when performance and type safety are critical. It is faster than SugaredLogger and allocates less, supporting only structured logging.

```go
logger, _ := zap.NewProduction()
deferr logger.Sync()
logger.Info("failed to fetch URL",
  // Structured context as strongly typed Field values.
  zap.String("url", url),
  zap.Int("attempt", 3),
  zap.Duration("backoff", time.Second),
)
```

--------------------------------

### Expected Go Module Dependency

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/antlr4-go/antlr/v4/README.md

This example illustrates the expected and clearer versioning for the ANTLR4 runtime when retrieved from the dedicated Go runtime repository.

```go
require (
    github.com/antlr/antlr4/runtime/Go/antlr/v4 v4.13.0
)
```

--------------------------------

### Build AMI with Specific Kubernetes Binaries

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/doc/usage/overview.md

Build the AMI using specific Kubernetes version, build date, and architecture values. These parameters override defaults and specify which binaries to install.

```bash
make k8s \
  kubernetes_version=1.23.9 \
  kubernetes_build_date=2022-07-27 \
  arch=x86_64
```

--------------------------------

### EKS Cluster Configuration for Testing

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/doc/CONTRIBUTING.md

Example `cluster.yaml` configuration file for creating an EKS cluster using `eksctl`. This is used to test if a newly built AMI can successfully join a cluster.

```yaml
apiVersion: eksctl.io/v1alpha5
kind: ClusterConfig

metadata:
  name: basic-cluster
  region: us-west-2
  version: '1.22'

nodeGroups:
  - name: ng
    instanceType: m5.large
    ami: [INSERT_AMI_ID]
    overrideBootstrapCommand: |
      #!/bin/bash
      /etc/eks/bootstrap.sh basic-cluster
```

--------------------------------

### Basic Struct Merge Example

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/dario.cat/mergo/README.md

Demonstrates a basic merge operation between two structs, showing how fields from the source struct populate zero-valued fields in the destination struct.

```go
package main

import (
	"fmt"
	"dario.cat/mergo"
)

type Foo struct {
	A string
	B int64
}

func main() {
	src := Foo{
		A: "one",
		B: 2,
	}
	dest := Foo{
		A: "two",
	}
	mergo.Merge(&dest, src)
	fmt.Println(dest)
	// Will print
	// {two 2}
}
```

--------------------------------

### go-toml v2 Interface Decoding Example

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/pelletier/go-toml/v2/README.md

Illustrates how go-toml v2 disregards existing interface values and decodes into a map[string]interface{} to match encoding/json behavior.

```go
package main

import (
	"fmt"
	"toml"
)

type inner struct {
	B interface{}
}
type doc struct {
	A interface{}
}

func main() {
	d := doc{
		A: inner{
			B: "Before",
		},
	}

	data := `
[A]
B = "After"
`

	toml.Unmarshal([]byte(data), &d)
	fmt.Printf("toml v2: %#v\n", d)

	// toml v2: main.doc{A:map[string]interface {}{"B":"After"}}
}
```

--------------------------------

### Example of Contextualized DecodeError

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/pelletier/go-toml/v2/README.md

Illustrates a typical DecodeError message from go-toml, showing the line number, the problematic part of the TOML document, and the specific decoding issue.

```text
1| [server]
2| path = 100
 |        ~~~ cannot decode TOML integer into struct field toml_test.Server.Path of type string
3| port = 50
```

--------------------------------

### Zap SugaredLogger Quick Start

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/go.uber.org/zap/README.md

Use SugaredLogger for contexts where performance is important but not critical. It supports both structured and printf-style APIs and is 4-10x faster than other structured logging packages.

```go
logger, _ := zap.NewProduction()
deferr logger.Sync() // flushes buffer, if any
sugar := logger.Sugar()
sugar.Infow("failed to fetch URL",
  // Structured context as loosely typed key-value pairs.
  "url", url,
  "attempt", 3,
  "backoff", time.Second,
)
sugar.Infof("Failed to fetch URL: %s", url)
```

--------------------------------

### go-toml v1 Array Bounds Error Example

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/pelletier/go-toml/v2/README.md

Shows how go-toml v1 returns an error when the TOML array length exceeds the destination array capacity.

```go
package main

import (
	"fmt"
	"toml"
)

type doc struct {
	A [2]string
}

func main() {
	d := doc{}
	err := toml.Unmarshal([]byte(`A = ["one", "two", "many"]`), &d)
	fmt.Println(err)

	// (1, 1): unmarshal: TOML array length (3) exceeds destination array length (2)
}
```

--------------------------------

### Serve mkdocs Site Locally

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/doc/development.md

Run this command to serve the mkdocs generated documentation site locally for development and previewing.

```bash
hack/mkdocs.sh serve
```

--------------------------------

### Incorrect Go Module Dependency

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/antlr4-go/antlr/v4/README.md

This example shows how `go get` might resolve ANTLR4 runtime versions when retrieved from the main ANTLR4 repository, leading to unclear versioning.

```go
require (
	github.com/antlr/antlr4/runtime/Go/antlr/v4 v4.0.0-20230219212500-1f9a474cc2dc
)
```

--------------------------------

### Get Last Error Directly Example

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/avast/retry-go/v5/README.md

Shows how to retrieve the last error directly from a `retry.Error` type, primarily for migration purposes from older versions of retry-go. It's generally recommended to use `errors.Is` or `errors.As` for error checking.

```go
if retryErr, ok := err.(retry.Error); ok {
		lastErr := retryErr.LastError()
	}
```

--------------------------------

### InstanceOptions

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/doc/api.md

Determines how the node's operating system and devices are configured.

```APIDOC
## InstanceOptions

### Description
InstanceOptions determines how the node's operating system and devices are configured.

### Fields
- `localStorage` (LocalStorageOptions) - 
- `environment` (EnvironmentOptions) - 
- `network` (NetworkOptions) - 
```

--------------------------------

### InstanceOptions

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/doc/nodeadm/doc/api.md

Determines how the node's operating system and devices are configured.

```APIDOC
## InstanceOptions

InstanceOptions determines how the node's operating system and devices are configured.

_Appears in:_
- [NodeConfigSpec](#nodeconfigspec)

| Field | Description |
| --- | --- |
| `localStorage` _[LocalStorageOptions](#localstorageoptions)_ |  |
| `environment` _[EnvironmentOptions](#environmentoptions)_ |  |
| `network` _[NetworkOptions](#networkoptions)_ |  |
```

--------------------------------

### List Binaries for a Specific Build Date and Platform

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/doc/usage/overview.md

List available binaries for a specific Kubernetes version, build date, and platform (e.g., linux) by querying the `amazon-eks` S3 bucket.

```bash
# List platforms
aws s3 ls s3://amazon-eks/1.23.9/2022-07-27/bin/
```

--------------------------------

### HTTP GET with Retry

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/avast/retry-go/v5/README.md

Performs an HTTP GET request with a specified number of attempts and delay. Handles reading the response body and returns an error if all attempts fail.

```go
url := "http://example.com"
var body []byte

err := retry.New(
	retry.Attempts(5),
	retry.Delay(100*time.Millisecond),
).Do(
	func() error {
		resp, err := http.Get(url)
		if err != nil {
			return err
		}
		defer resp.Body.Close()
		body, err = ioutil.ReadAll(resp.Body)
		if err != nil {
			return err
		}
		return nil
	},
)

if err != nil {
	// handle error
}

fmt.Println(string(body))
```

--------------------------------

### Configure Pause Container Image

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/doc/usage/al2023.md

Example of modifying the pause container image reference in containerd's config.toml. This example shows how to switch from an ECR image to a public Kubernetes image.

```diff
-<ACCOUNT_ID>.dkr.ecr.<REGION>.<DOMAIN>"
+<ACCOUNT_ID>.dkr.ecr-fips.<REGION>.<DOMAIN>"
```

--------------------------------

### HTTP GET with Retry and Data Handling

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/avast/retry-go/v5/README.md

Executes an HTTP GET request with retry logic and returns the response body as data. This is useful when the operation needs to return a value upon success.

```go
url := "http://example.com"

body, err := retry.DoWithData(retry.New(),
	func() ([]byte, error) {
		resp, err := http.Get(url)
		if err != nil {
			return nil, err
		}
		defer resp.Body.Close()
		body, err := ioutil.ReadAll(resp.Body)
		if err != nil {
			return nil, err
		}

		return body, nil
	},
)

if err != nil {
	// handle error
}

fmt.Println(string(body))
```

--------------------------------

### Initialize Block Device FS and Get Disk Stats

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/prometheus/procfs/README.md

Initialize a filesystem object that requires access to both /proc and /sys, then retrieve block device statistics. Use this for detailed disk I/O metrics.

```go
fs, err := blockdevice.NewFS("/proc", "/sys")
stats, err := fs.ProcDiskstats()
```

--------------------------------

### Update Objx

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/stretchr/objx/README.md

Update the Objx package to the latest version using the go get -u command.

```bash
go get -u github.com/stretchr/objx
```

--------------------------------

### Troubleshooting `realpath: command not found`

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/doc/CONTRIBUTING.md

When running `make test`, this error may occur. Installing `coreutils` on OSX can resolve this issue.

```bash
test/test-harness.sh: line 41: realpath: command not found
/entrypoint.sh: line 13: /test.sh: No such file or directory
```

--------------------------------

### Logging to a Single File with klog

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/k8s.io/klog/v2/README.md

Demonstrates how to configure klog to log to a single file using the 'log_file' flag, an alternative to 'log_dir'.

```go
// See examples/log_file/usage_log_file.go
```

--------------------------------

### Declare and Use Subcommand with Flag

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/integrii/flaggy/README.md

Demonstrates how to declare a subcommand, add a string flag to it, and parse arguments. Use this when your application has distinct operational modes represented by subcommands.

```go
var stringFlag = "defaultValue"

subcommand := flaggy.NewSubcommand("subcommandExample")

subcommand.String(&stringFlag, "f", "flag", "A test string flag")

flaggy.AttachSubcommand(subcommand, 1)

flaggy.Parse()

print(stringFlag)
```

--------------------------------

### Convert Between JSON and YAML

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/sigs.k8s.io/yaml/README.md

Provides examples for converting JSON data to YAML using yaml.JSONToYAML and YAML data to JSON using yaml.YAMLToJSON.

```APIDOC
## Convert Between JSON and YAML

### Description
This section demonstrates the utility functions `yaml.JSONToYAML` for converting JSON byte slices to YAML byte slices, and `yaml.YAMLToJSON` for converting YAML byte slices to JSON byte slices.

### Usage

```go
package main

import (
	"fmt"

	"sigs.k8s.io/yaml"
)

func main() {
	j := []byte(`{"name": "John", "age": 30}`)
	y, err := yaml.JSONToYAML(j)
	if err != nil {
		fmt.Printf("err: %v\n", err)
		return
	}
	fmt.Println(string(y))
	/* Output:
	age: 30
	name: John
	*/
	j2, err := yaml.YAMLToJSON(y)
	if err != nil {
		fmt.Printf("err: %v\n", err)
		return
	}
	fmt.Println(string(j2))
	/* Output:
	{"age":30,"name":"John"}
	*/
}
```
```

--------------------------------

### Coexisting with glog and klog

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/k8s.io/klog/v2/README.md

Illustrates how to initialize and synchronize flags between glog and klog, and redirect output to stderr.

```go
// See examples/coexist_glog/coexist_glog.go
```

--------------------------------

### Get/Set Interface{} Value with reflect2

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/modern-go/reflect2/README.md

Demonstrates how to get and set values of an interface{}. Always use the pointer representation of the type for get/set operations.

```go
valType := reflect2.TypeOf(1)
i := 1
j := 10
valType.Set(&i, &j)
// i will be 10
```

--------------------------------

### Create a New Feature Branch

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/go.uber.org/zap/CONTRIBUTING.md

Start a new branch for your feature development. It's recommended to rebase on the latest upstream master before branching.

```bash
cd $GOPATH/src/go.uber.org/zap
git checkout master
git fetch upstream
git rebase upstream/master
git checkout -b cool_new_feature
```

--------------------------------

### Get Integer Value from FlagSet

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/spf13/pflag/README.md

Retrieve the integer value of a flag from a pflag.FlagSet using GetInt(). This method requires the flag to exist and be of type int.

```go
i, err := flagset.GetInt("flagname")
```

--------------------------------

### Build AMI Using Custom Binary Bucket

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/doc/usage/overview.md

Build the AMI using Kubernetes binaries from your own S3 bucket. Specify the bucket name, region, and the Kubernetes version/build date that corresponds to your binaries.

```bash
make k8s \
  binary_bucket_name=my-custom-bucket \
  binary_bucket_region=eu-west-1 \
  kubernetes_version=1.14.9 \
  kubernetes_build_date=2020-01-22
```

--------------------------------

### Updating Mergo Locally

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/dario.cat/mergo/README.md

To update your local copy of Mergo to the latest version, use the 'go get -u' command with the new vanity URL.

```go
go get -u dario.cat/mergo
```

--------------------------------

### Run Go Benchmarks

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/pelletier/go-toml/v2/AGENTS.md

Execute all benchmarks in the project multiple times to ensure consistent results. This is used to verify performance requirements and detect regressions.

```bash
go test ./... -bench=. -count=10
```

--------------------------------

### Use tomljson via Docker

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/pelletier/go-toml/v2/README.md

Runs the tomljson tool using a Docker container. This is useful for converting TOML to JSON without installing the tool locally.

```bash
docker run -i ghcr.io/pelletier/go-toml:v2 tomljson < example.toml
```

--------------------------------

### Basic Info Log

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/k8s.io/klog/v2/README.md

Use glog.Info for standard informational messages.

```go
glog.Info("Prepare to repel boarders")
```

--------------------------------

### Setting Version at Build Time with Go

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/integrii/flaggy/README.md

Builds an application and sets the version string using Go's linker flags. This is useful for embedding version information directly into the executable.

```bash
# build your app and set the version string
$ go build -ldflags='-X main.version=1.0.3-a3db3'
$ ./yourApp version
Version: 1.0.3-a3db3
$ ./yourApp --help
Test Program - A little example program
http://github.com/integrii/flaggy

```

--------------------------------

### List Specific Binaries for an Architecture

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/doc/usage/overview.md

List specific binaries available for a given Kubernetes version, build date, platform, and architecture by querying the `amazon-eks` S3 bucket.

```bash
# List binaries
aws s3 ls s3://amazon-eks/1.23.9/2022-07-27/bin/linux/x86_64/
```

--------------------------------

### Set Retry Context

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/avast/retry-go/v5/README.md

Use the Context option to set a custom context for retry operations. This allows for cancellation or timeouts. Example shows immediate cancellation.

```go
ctx, cancel := context.WithCancel(context.Background())
cancel()

retry.New().Do(
	func() error {
		...
	},
	retry.Context(ctx),
)
```

--------------------------------

### Build EKS-Optimized AMI with Packer

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/doc/README.md

Initiate the AMI build process using the provided Makefile. Specify the desired Kubernetes version and operating system distribution.

```bash
make k8s=1.29 os_distro=al2023
```

```bash
make help
```

--------------------------------

### Custom Transformer for time.Time

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/dario.cat/mergo/README.md

Implement a custom transformer to merge time.Time structs. This example shows how to merge a non-zero time.Time value by checking if the destination is zero.

```go
package main

import (
	"fmt"
	"dario.cat/mergo"
    "reflect"
    "time"
)

type timeTransformer struct {
}

func (t timeTransformer) Transformer(typ reflect.Type) func(dst, src reflect.Value) error {
	if typ == reflect.TypeOf(time.Time{}) {
		return func(dst, src reflect.Value) error {
			if dst.CanSet() {
				isZero := dst.MethodByName("IsZero")
				result := isZero.Call([]reflect.Value{})
				if result[0].Bool() {
					dst.Set(src)
				}
			}
			return nil
		}
	}
	return nil
}

type Snapshot struct {
	Time time.Time
	// ...
}

func main() {
	src := Snapshot{time.Now()}
	dest := Snapshot{}
	mergo.Merge(&dest, src, mergo.WithTransformers(timeTransformer{}))
	fmt.Println(dest)
	// Will print
	// { 2018-01-12 01:15:00 +0000 UTC m=+0.000000001 }
}
```

--------------------------------

### Example Commit Message

Source: https://github.com/awslabs/amazon-eks-ami/blob/main/nodeadm/vendor/github.com/godbus/dbus/v5/CONTRIBUTING.md

Follow this format for commit messages to clearly indicate what changed and why. The subject line should be concise, followed by a blank line, and then a more detailed explanation.

```git
scripts: add the test-cluster command

this uses tmux to setup a test cluster that you can easily kill and
start for debugging.

Fixes #38
```