### Install dataurl Package

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/vincent-petithory/dataurl/README.md

Use go get to install the dataurl package.

```go
go get github.com/vincent-petithory/dataurl
```

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

### Install IAM Go Client

Source: https://github.com/coreos/ignition/blob/main/vendor/cloud.google.com/go/iam/README.md

Use 'go get' to install the IAM Go client library. This command fetches and installs the package and its dependencies.

```bash
go get cloud.google.com/go/iam
```

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

### Install and Run Local Go Doc Site

Source: https://github.com/coreos/ignition/blob/main/vendor/go.opentelemetry.io/otel/CONTRIBUTING.md

Installs and runs a local Go Doc site using pkgsite. Ensure you have Go installed and configured.

```sh
go install golang.org/x/pkgsite/cmd/pkgsite@latest
pkgsite
```

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

### Install copystructure Go Library

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/mitchellh/copystructure/README.md

Use `go get` to install the copystructure library. This is the standard method for obtaining Go packages.

```bash
$ go get github.com/mitchellh/copystructure
```

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

### Install Azure Blob Storage SDK for Go

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/Azure/azure-sdk-for-go/sdk/storage/azblob/README.md

Install the Azure Blob Storage client module for Go using go get.

```bash
go get github.com/Azure/azure-sdk-for-go/sdk/storage/azblob
```

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

### Install UUID Package

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/google/uuid/README.md

Use this command to install the UUID package using go get.

```sh
go get github.com/google/uuid
```

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

### Install godbus/dbus

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/godbus/dbus/v5/README.md

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

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

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

### Create Azure Storage Account using Azure CLI

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/Azure/azure-sdk-for-go/sdk/storage/azblob/README.md

Example of creating an Azure storage account using the Azure CLI. Ensure you have the Azure CLI installed and configured.

```bash
az storage account create --name MyStorageAccount --resource-group MyResourceGroup --location westus --sku Standard_LRS
```

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

### Install Google Auth Library for Go

Source: https://github.com/coreos/ignition/blob/main/vendor/cloud.google.com/go/auth/README.md

Use this command to install the latest version of the Google Auth library for Go.

```bash
go get cloud.google.com/go/auth@latest
```

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

### Install Azure Identity SDK for Go

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/Azure/azure-sdk-for-go/sdk/storage/azblob/README.md

If you plan to authenticate with Azure Active Directory, install the azidentity module as well.

```bash
go get github.com/Azure/azure-sdk-for-go/sdk/azidentity
```

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

### Install Compute Metadata Library

Source: https://github.com/coreos/ignition/blob/main/vendor/cloud.google.com/go/compute/metadata/README.md

Use this command to install the compute metadata library for your Go project.

```bash
go get cloud.google.com/go/compute/metadata
```

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

### Install the Azure Identity Module

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/Azure/azure-sdk-for-go/sdk/azidentity/README.md

Installs the Azure Identity module using Go modules.

```sh
go get -u github.com/Azure/azure-sdk-for-go/sdk/azidentity
```

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

### Application Setup with logr Logger

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/go-logr/logr/README.md

Demonstrates how to initialize a logr.Logger with a specific implementation early in an application's lifecycle. This logger can then be passed to other parts of the application.

```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 ...
}
```

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

### Enable and Start a Systemd Service

Source: https://github.com/coreos/ignition/blob/main/docs/examples.md

Write a new systemd service unit that is enabled and starts on boot as a dependency of multi-user.target.

```json
{
  "ignition": { "version": "3.0.0" },
  "systemd": {
    "units": [{
      "name": "example.service",
      "enabled": true,
      "contents": "[Service]\nType=oneshot\nExecStart=/usr/bin/echo Hello World\n\n[Install]\nWantedBy=multi-user.target"
    }]
  }
}
```

```ini
[Service]
Type=oneshot
ExecStart=/usr/bin/echo Hello World

[Install]
WantedBy=multi-user.target
```

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

### Start TFTP Server

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/pin/tftp/README.md

Initializes and starts a new TFTP server with specified read and write handlers. The server listens on UDP port 69 and blocks until Shutdown is called. An optional timeout can be set.

```go
func main() {
	// use nil in place of handler to disable read or write operations
	s := tftp.NewServer(readHandler, writeHandler)
	s.SetTimeout(5 * time.Second) // optional
	err := s.ListenAndServe(":69") // blocks until s.Shutdown() is called
	if err != nil {
		fmt.Fprintf(os.Stdout, "server: %v\n", err)
		os.Exit(1)
	}
}

```

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

### Install blkid Headers

Source: https://github.com/coreos/ignition/blob/main/docs/development.md

Install the blkid development headers required for Ignition. Choose the command appropriate for your Linux distribution.

```sh
# Debian/Ubuntu
sudo apt-get install libblkid-dev

# RPM-based
sudo dnf install libblkid-devel
```

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

### Install gRPC-Go

Source: https://github.com/coreos/ignition/blob/main/vendor/google.golang.org/grpc/README.md

Add this import statement to your Go code to automatically fetch gRPC-Go dependencies during build, run, or test.

```go
import "google.golang.org/grpc"
```

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

### Set Kernel Arguments

Source: https://github.com/coreos/ignition/blob/main/docs/examples.md

Configures kernel arguments, ensuring 'example' and 'foo bar' exist while 'somekarg' is removed. This is useful for system boot-time configurations.

```json
{
  "ignition": {"version": "3.3.0"},
  "kernelArguments": {
    "shouldExist": ["example", "foo bar"],
    "shouldNotExist": ["somekarg"]
  }
}
```

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

### Configure Go Client Code Generation

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/aws/smithy-go/README.md

Example smithy-build.json configuration for the `go-codegen` plugin. Specifies the service, module, and Go directive 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"
    }
  }
}
```

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

### Define Exporter Interface

Source: https://github.com/coreos/ignition/blob/main/vendor/go.opentelemetry.io/otel/CONTRIBUTING.md

Example of defining a basic Exporter interface.

```go
type Exporter interface {
	Export()
}
```

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

### Commit Convention Example

Source: https://github.com/coreos/ignition/blob/main/AGENTS.md

Illustrates the expected format for commit messages in the Ignition project, emphasizing a subsystem prefix, lowercase description, and imperative mood.

```git
providers/hetzner: add Hetzner Cloud support

```

```git
config/v3_6: stabilize spec

```

```git
internal/exec/stages/files: fix permission handling

```

```git
docs: update supported platforms

```

```git
*: refactor provider interface

```

```git
tests: add filesystem blackbox tests

```

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

### Initialize Observability Explicitly

Source: https://github.com/coreos/ignition/blob/main/vendor/go.opentelemetry.io/otel/CONTRIBUTING.md

Encapsulate observability setup in constructor functions for clear ownership and scope, ensuring it's explicit and side-effect free.

```go
import (
	"errors"

	semconv "go.opentelemetry.io/otel/semconv/v1.40.0"
	"go.opentelemetry.io/otel/semconv/v1.40.0/otelconv"
)

type SDKComponent struct {
    inst *instrumentation
}

func NewSDKComponent(config Config) (*SDKComponent, error) {
    inst, err := newInstrumentation()
    if err != nil {
        return nil, err
    }
    return &SDKComponent{inst: inst}, nil
}

type instrumentation struct {
    inflight otelconv.SDKComponentInflight
    exported otelconv.SDKComponentExported
}

func newInstrumentation() (*instrumentation, error) {
    if !x.Observability.Enabled() {
        return nil, nil
    }
 
    meter := otel.GetMeterProvider().Meter(
        "<component-package-name>",
        metric.WithInstrumentationVersion(sdk.Version()),
        metric.WithSchemaURL(semconv.SchemaURL),
    )

	inst := &instrumentation{}

	var err, e error
    inst.inflight, e = otelconv.NewSDKComponentInflight(meter)
	err = errors.Join(err, e)

    inst.exported, e = otelconv.NewSDKComponentExported(meter)
	err = errors.Join(err, e)

    return inst, err
}
```

```go
// ❌ Avoid this pattern.
func (c *Component) initObservability() {
	// Initialize observability metrics
	if !x.Observability.Enabled() {
		return
	}

	// Initialize observability metrics
	c.inst = &instrumentation{/* ... */}
}
```

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

### Managed identity authentication with autorest/adal

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/Azure/azure-sdk-for-go/sdk/azidentity/MIGRATION.md

This example shows how to authenticate using a managed identity with the autorest/adal package by creating a service principal token from a managed identity.

```go
import (
    "github.com/Azure/azure-sdk-for-go/services/resources/mgmt/2018-06-01/subscriptions"
    "github.com/Azure/go-autorest/autorest"
    "github.com/Azure/go-autorest/autorest/adal"
)

spt, err := adal.NewServicePrincipalTokenFromManagedIdentity("https://management.azure.com/", nil)
handle(err)

client := subscriptions.NewClient()
client.Authorizer = autorest.NewBearerAuthorizer(spt)
```

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

### Create a Cloud Storage Client

Source: https://github.com/coreos/ignition/blob/main/vendor/cloud.google.com/go/storage/README.md

Initialize a storage.Client to be used for all subsequent operations. Handle potential errors during client creation.

```go
client, err := storage.NewClient(ctx)
if err != nil {
	log.Fatal(err)
}
```

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

### Create New Configuration Instance

Source: https://github.com/coreos/ignition/blob/main/vendor/go.opentelemetry.io/otel/CONTRIBUTING.md

Creates a new configuration instance by applying a variadic list of options to a default config struct. This function is usually unexported.

```go
// newConfig returns an appropriately configured config.
func newConfig(options ...Option) config {
	// Set default values for config.
	config := config{/* […] */}
	for _, option := range options {
		config = option.apply(config)
	}
	// Perform any validation here.
	return config
}
```

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

### Create and Indent XML Document

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/beevik/etree/README.md

Creates a new XML document from scratch, adds processing instructions and elements, indents it, and writes it to standard output. Ensure the 'os' package is imported for os.Stdout.

```go
doc := etree.NewDocument()
doc.CreateProcInst("xml", `version="1.0" encoding="UTF-8"`)
doc.CreateProcInst("xml-stylesheet", `type="text/xsl" href="style.xsl"`)

people := doc.CreateElement("People")
people.CreateComment("These are all known people")

jon := people.CreateElement("Person")
jon.CreateAttr("name", "Jon")

sally := people.CreateElement("Person")
sally.CreateAttr("name", "Sally")

doc.Indent(2)
doc.WriteTo(os.Stdout)
```

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

### Get OpenTelemetry Go Package

Source: https://github.com/coreos/ignition/blob/main/vendor/go.opentelemetry.io/otel/CONTRIBUTING.md

Use `go get` to download the opentelemetry-go package. This command may produce warnings that can be ignored.

```go
go get -d go.opentelemetry.io/otel
```

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

### Install Schematyper for Go Struct Generation

Source: https://github.com/coreos/ignition/blob/main/docs/development.md

Install the schematyper tool to generate Go structs from JSON schema definitions. This is a prerequisite for modifying the Ignition config spec.

```sh
go get -u github.com/idubinskiy/schematyper
```

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

### Update Dependencies using go get and go mod tidy

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/golang-jwt/jwt/v5/MIGRATION_GUIDE.md

After changing the import path, update your project's dependencies using 'go get' and 'go mod tidy' to incorporate the new library version.

```bash
go get github.com/golang-jwt/jwt/v4
go mod tidy
```

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

### Client certificate authentication with autorest/adal

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/Azure/azure-sdk-for-go/sdk/azidentity/MIGRATION.md

This example shows how to authenticate using a client certificate with the autorest/adal package. It reads the certificate, decodes it, and then creates a service principal token.

```go
import (
    "os"

    "github.com/Azure/azure-sdk-for-go/services/resources/mgmt/2018-06-01/subscriptions"
    "github.com/Azure/go-autorest/autorest"
    "github.com/Azure/go-autorest/autorest/adal"
)
certData, err := os.ReadFile("./example.pfx")
handle(err)

certificate, rsaPrivateKey, err := decodePkcs12(certData, "")
handle(err)

oauthCfg, err := adal.NewOAuthConfig("https://login.microsoftonline.com", tenantID)
handle(err)

spt, err := adal.NewServicePrincipalTokenFromCertificate(
    *oauthConfig, clientID, certificate, rsaPrivateKey, "https://management.azure.com/",
)

client := subscriptions.NewClient()
client.Authorizer = autorest.NewBearerAuthorizer(spt)
```

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

### Import Golang JWT Package

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/golang-jwt/jwt/v5/README.md

Import the jwt package into your Go code after installation.

```go
import "github.com/golang-jwt/jwt/v5"
```

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

### Install Golang JWT Package

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/golang-jwt/jwt/v5/README.md

Use this command to add the jwt-go package as a dependency in your Go program.

```sh
go get -u github.com/golang-jwt/jwt/v5
```

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

### Client certificate authentication with azidentity

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/Azure/azure-sdk-for-go/sdk/azidentity/MIGRATION.md

This snippet demonstrates authenticating using a client certificate with the azidentity package. It parses the certificate data and then creates a new subscriptions client.

```go
import (
    "os"

    "github.com/Azure/azure-sdk-for-go/sdk/azidentity"
    "github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/resources/armsubscriptions"
)

certData, err := os.ReadFile("./example.pfx")
handle(err)

certs, key, err := azidentity.ParseCertificates(certData, nil)
handle(err)

cred, err = azidentity.NewClientCertificateCredential(tenantID, clientID, certs, key, nil)
handle(err)

client, err := armsubscriptions.NewClient(cred, nil)
handle(err)
```

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

### Run All Blackbox Tests

Source: https://github.com/coreos/ignition/blob/main/docs/development.md

Execute all blackbox tests. Ensure you have the necessary host system dependencies installed.

```sh
./build_blackbox_tests
sudo sh -c 'PATH=$PWD/bin/amd64:$PATH ./tests.test'
```

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

### Configure HTTP Pipeline Options

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/Azure/azure-sdk-for-go/sdk/storage/azblob/migrationguide.md

Configure HTTP pipeline options by passing an azcore.ClientOptions struct to the azblob.ClientOptions when creating a new client.

```go
client, err := azblob.NewClient(account, cred, &azblob.ClientOptions{
	ClientOptions: azcore.ClientOptions{
		// configure HTTP pipeline options here
	},
})
```

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

### Find books by price using compiled path

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/beevik/etree/README.md

Finds all books with a price of 49.99 and outputs their titles. This example demonstrates using a pre-compiled path for efficiency when the same path is used multiple times.

```go
path := etree.MustCompilePath("./bookstore/book[p:price='49.99']/title")
for _, e := range doc.FindElementsPathSeq(path) {
    fmt.Println(e.Text())
}
```

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

### Deprecate a Flag

Source: https://github.com/coreos/ignition/blob/main/vendor/github.com/spf13/pflag/README.md

Shows how to mark a flag as deprecated, providing a message to guide users to the recommended alternative.

```go
// deprecate a flag by specifying its name and a usage message
flags.MarkDeprecated("badflag", "please use --good-flag instead")
```

```go
// deprecate a flag shorthand by specifying its flag name and a usage message
flags.MarkShorthandDeprecated("noshorthandflag", "please use --noshorthandflag only")
```

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

### Define Additional Closer Interface

Source: https://github.com/coreos/ignition/blob/main/vendor/go.opentelemetry.io/otel/CONTRIBUTING.md

Example of defining a new interface to add functionality (Close) to an existing type.

```go
type Closer interface {
	Close()
}
```

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

### Deterministic Testing Setup in Go

Source: https://github.com/coreos/ignition/blob/main/vendor/go.opentelemetry.io/otel/CONTRIBUTING.md

Isolate the meter provider and use t.Setenv for environment variables to ensure deterministic testing. Reset global state like component ID counters.

```go
func TestObservability(t *testing.T) {
	// Restore state after test to ensure this does not affect other tests.
    prev := otel.GetMeterProvider()
    t.Cleanup(func() {
        otel.SetMeterProvider(prev)
    })

    // Isolate the meter provider for deterministic testing
    reader := metric.NewManualReader()
    meterProvider := metric.NewMeterProvider(metric.WithReader(reader))
    otel.SetMeterProvider(meterProvider)

	// Use t.Setenv to ensure environment variable is restored after test.
    t.Setenv("OTEL_GO_X_OBSERVABILITY", "true")

	// Reset component ID counter to ensure deterministic component names.
	componentIDCounter.Store(0)
 
	/* ... test code ... */
}
```

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

### Define Super-set Interface Type

Source: https://github.com/coreos/ignition/blob/main/vendor/go.opentelemetry.io/otel/CONTRIBUTING.md

Example of creating a new type that embeds an existing interface and adds new methods.

```go
type ClosingExporter struct {
	Exporter
	Close()
}
```

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

### Get GPG Key ID

Source: https://github.com/coreos/ignition/blob/main/vendor/go.opentelemetry.io/otel/RELEASING.md

Retrieve your GPG key ID, which is required for signing release artifacts. The ID is a 16-character string.

```terminal
gpg --list-secret-keys --keyid-format=long
```