### Install color package

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/cppforlife/color/README.md

Use 'go get' to install the color package.

```bash
go get github.com/fatih/color
```

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

### Install go-yaml.v2

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/sigs.k8s.io/yaml/goyaml.v2/README.md

Use 'go get' to install the go-yaml.v2 package.

```bash
go get gopkg.in/yaml.v2
```

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

### Install go-version Library

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/hashicorp/go-version/README.md

Install the go-version library using the standard go get command.

```bash
$ go get github.com/hashicorp/go-version
```

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

### Build FreePort from Source

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/phayes/freeport/README.md

Install Go and then use 'go get' to download and install the FreePort library from source.

```bash
sudo apt-get install golang                    # Download go. Alternativly build from source: https://golang.org/doc/install/source
go get github.com/phayes/freeport
```

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

### Install go-isatty Package

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/mattn/go-isatty/README.md

Install the go-isatty package using the go get command.

```bash
go get github.com/mattn/go-isatty
```

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

### Install Cobra Library

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/spf13/cobra/README.md

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

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

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

### Install go-autorest/autorest/adal

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/Azure/go-autorest/autorest/adal/README.md

Install the Azure Active Directory authentication library for Go using go get.

```bash
go get -u github.com/Azure/go-autorest/autorest/adal
```

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

### Install Doublestar Package

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/bmatcuk/doublestar/README.md

Use `go get` to install the doublestar package. This command fetches and installs the package and its dependencies.

```bash
go get github.com/bmatcuk/doublestar
```

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

### Install uniseg Package

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/rivo/uniseg/README.md

Use 'go get' to install the uniseg package for your Go project.

```bash
go get github.com/rivo/uniseg
```

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

### Install and Import Kubernetes YAML Library

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/sigs.k8s.io/yaml/README.md

Install the library using 'go get' and import it into your Go projects for YAML processing.

```bash
go get sigs.k8s.io/yaml
```

```go
import "sigs.k8s.io/yaml"
```

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

### Define a WebService with Routes

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/emicklei/go-restful/README.md

Example of creating a WebService, defining its path, supported content types, and a GET route for retrieving a user. The route specifies the handler function, documentation, path parameters, and the expected response type.

```go
ws := new(restful.WebService)
ws.
	Path("/users").
	Consumes(restful.MIME_XML, restful.MIME_JSON).
	Produces(restful.MIME_JSON, restful.MIME_XML)

ws.Route(ws.GET("/{user-id}").To(u.findUser).
	Doc("get a user").
	Param(ws.PathParameter("user-id", "identifier of the user").DataType("string")),
	Writes(User{}))		
...

func (u UserResource) findUser(request *restful.Request, response *restful.Response) {
	id := request.PathParameter("user-id")
	...
}
```

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

### Install json-iterator/go

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/json-iterator/go/README.md

Install the library using the go get command. This is the standard method for adding Go packages to your project.

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

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

### Install go-autorest Libraries

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/Azure/go-autorest/README.md

Provides the go get commands to install the core go-autorest libraries and its subpackages.

```bash
go get github.com/Azure/go-autorest/autorest
go get github.com/Azure/go-autorest/autorest/azure
go get github.com/Azure/go-autorest/autorest/date
go get github.com/Azure/go-autorest/autorest/to
```

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

### Install go-colorable Package

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/mattn/go-colorable/README.md

Install the go-colorable package using the go get command. This is the standard method for adding Go dependencies to your project.

```bash
go get github.com/mattn/go-colorable
```

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

### Install Compute API Go Package

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/cloud.google.com/go/compute/metadata/README.md

Use this command to install the compute metadata Go package.

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

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

### Run ytt Examples Locally

Source: https://github.com/carvel-dev/vendir/blob/develop/examples/git-shallow/vendor/deeper-sha/README.md

Execute ytt examples from the playground directory using the command line. This command processes the specified directory and outputs the results.

```bash
ytt -f examples/playground/example-demo/
```

```bash
ytt -f examples/playground/example-demo/ --output-directory tmp/
```

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

### Persistence Configuration Example

Source: https://github.com/carvel-dev/vendir/blob/develop/examples/helm-chart-oci/vendor/custom-repo-custom-version/charts/common/README.md

An example configuration for the Persistence section, detailing enabled status, storage class, access mode, size, and path.

```yaml
enabled: true
storageClass: "-"
accessMode: ReadWriteOnce
size: 8Gi
path: /bitnami
```

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

### Golang Example for FreePort

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/phayes/freeport/README.md

This Go code demonstrates how to use the freeport library to get an available TCP port. Ensure error handling for the GetFreePort function.

```go
package main

import "github.com/phayes/freeport"

func main() {
	port, err := freeport.GetFreePort()
	if err != nil {
		log.Fatal(err)
	}
	// port is ready to listen on
}
```

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

### Install Gonum LAPACK Packages

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/gonum.org/v1/gonum/lapack/README.md

Use this command to install all Gonum LAPACK packages. Ensure you have Go installed and configured.

```bash
go get gonum.org/v1/gonum/lapack/...
```

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

### ImageRoot Configuration Example

Source: https://github.com/carvel-dev/vendir/blob/develop/examples/helm-chart-oci/vendor/custom-repo-custom-version/charts/common/README.md

An example configuration for the ImageRoot section, specifying registry, repository, tag, pull policy, and debug settings.

```yaml
registry: docker.io
repository: bitnami/nginx
tag: 1.16.1-debian-10-r63
pullPolicy: IfNotPresent
debug: false
```

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

### Credential Helper Configuration Example

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/google/go-containerregistry/pkg/authn/README.md

Modify your configuration file to use custom credential helpers. This example maps 'gcr.io' to the 'tee' helper and 'eu.gcr.io' to the 'hardcoded' helper.

```json
{
	"credHelpers": {
		"gcr.io": "tee",
		"eu.gcr.io": "hardcoded"
	}
}
```

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

### Helm Validation NOTES.txt Example

Source: https://github.com/carvel-dev/vendir/blob/develop/examples/helm-chart-oci/vendor/custom-repo-custom-version/charts/common/README.md

A NOTES.txt example demonstrating how to use common.validations.values.multiple.empty to enforce non-empty values, with corresponding command-line overrides.

```yaml
{{- $validateValueConf00 := (dict "valueKey" "path.to.value00" "secret" "secretName" "field" "password-00") -}}
{{- $validateValueConf01 := (dict "valueKey" "path.to.value01" "secret" "secretName" "field" "password-01") -}}

{{ include "common.validations.values.multiple.empty" (dict "required" (list $validateValueConf00 $validateValueConf01) "context" $) }}
```

```console
$ helm install test mychart --set path.to.value00="",path.to.value01=""
    'path.to.value00' must not be empty, please add '--set path.to.value00=$PASSWORD_00' to the command. To get the current value:

        export PASSWORD_00=$(kubectl get secret --namespace default secretName -o jsonpath="{.data.password-00}" | base64 --decode)

    'path.to.value01' must not be empty, please add '--set path.to.value01=$PASSWORD_01' to the command. To get the current value:

        export PASSWORD_01=$(kubectl get secret --namespace default secretName -o jsonpath="{.data.password-01}" | base64 --decode)
```

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

### Install Bats Core

Source: https://github.com/carvel-dev/vendir/blob/develop/examples/image/vendor/docker.io/dkalinin/consul-helm-by-tag/README.md

Installs the Bats-core testing framework using Homebrew. This is a prerequisite for running unit and acceptance tests.

```bash
brew install bats-core
```

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

### Install yq

Source: https://github.com/carvel-dev/vendir/blob/develop/examples/image/vendor/docker.io/dkalinin/consul-helm-by-tag/README.md

Installs the yq tool using Homebrew, which is a prerequisite for running tests. yq is used for processing YAML files.

```bash
brew install python-yq
```

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

### Persistence Configuration Example

Source: https://github.com/carvel-dev/vendir/blob/develop/examples/helm-chart-oci-dependencies/vendor/custom-repo-custom-version/charts/contour/charts/common/README.md

Configures persistent storage for a deployment, including storage class, access mode, size, and path.

```yaml
enabled:
  type: boolean
  description: Whether enable persistence.
  example: true

storageClass:
  type: string
  description: Ghost data Persistent Volume Storage Class, If set to "-", storageClassName: "" which disables dynamic provisioning.
  example: "-"

accessMode:
  type: string
  description: Access mode for the Persistent Volume Storage.
  example: ReadWriteOnce

size:
  type: string
  description: Size the Persistent Volume Storage.
  example: 8Gi

path:
  type: string
  description: Path to be persisted.
  example: /bitnami

## An instance would be:
# enabled: true
# storageClass: "-"
# accessMode: ReadWriteOnce
# size: 8Gi
# path: /bitnami
```

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

### Install Consul Helm Chart

Source: https://github.com/carvel-dev/vendir/blob/develop/examples/image/vendor/docker.io/dkalinin/consul-helm-by-tag/README.md

Installs the Consul Helm chart directly from a local directory. Ensure the repository is downloaded and unpacked.

```bash
helm install ./consul-helm
```

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

### ExistingSecret Configuration Example

Source: https://github.com/carvel-dev/vendir/blob/develop/examples/helm-chart-oci/vendor/custom-repo-custom-version/charts/common/README.md

An example configuration for the ExistingSecret section, showing how to reference an existing secret and map its keys.

```yaml
name: mySecret
keyMapping:
  password: myPasswordKey
```

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

### ImageRoot Configuration Example

Source: https://github.com/carvel-dev/vendir/blob/develop/examples/helm-chart-oci-dependencies/vendor/custom-repo-custom-version/charts/contour/charts/common/README.md

Defines parameters for specifying a Docker image, including registry, repository, tag, and pull policy.

```yaml
registry:
  type: string
  description: Docker registry where the image is located
  example: docker.io

repository:
  type: string
  description: Repository and image name
  example: bitnami/nginx

tag:
  type: string
  description: image tag
  example: 1.16.1-debian-10-r63

pullPolicy:
  type: string
  description: Specify a imagePullPolicy. Defaults to 'Always' if image tag is 'latest', else set to 'IfNotPresent'

pullSecrets:
  type: array
  items:
    type: string
  description: Optionally specify an array of imagePullSecrets (evaluated as templates).

debug:
  type: boolean
  description: Set to true if you would like to see extra information on logs
  example: false

## An instance would be:
# registry: docker.io
# repository: bitnami/nginx
# tag: 1.16.1-debian-10-r63
# pullPolicy: IfNotPresent
# debug: false
```

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

### Install Contour Helm Chart

Source: https://github.com/carvel-dev/vendir/blob/develop/examples/helm-chart-oci-dependencies/vendor/custom-repo-custom-version/charts/contour/README.md

Add the Bitnami Helm repository and install the Contour chart with a release name. This deploys the Contour Ingress Controller and Envoy Proxy.

```bash
helm repo add bitnami https://charts.bitnami.com/bitnami
helm install my-release bitnami/contour
```

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

### Create Root Logger

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/go-logr/logr/README.md

Demonstrates how to create the initial 'root' logger in an application's main function, choosing a specific logging implementation.

```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 ...

```

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

### URL Path Preparation Example

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/Azure/go-autorest/README.md

Illustrates how multiple WithPath decorators can be used to sequentially build a URL path during request preparation. The final URL will be a concatenation of the base URL and all provided path segments.

```go
req, err := Prepare(&http.Request{}, \
    WithBaseURL("https://microsoft.com/"), \
    WithPath("a"), \
    WithPath("b"), \
    WithPath("c"))
```

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

### Set Helm Chart Parameters

Source: https://github.com/carvel-dev/vendir/blob/develop/examples/helm-chart-oci-dependencies/vendor/custom-repo-custom-version/charts/contour/README.md

Use the `--set` argument with `helm install` to configure chart parameters. This example shows how to set a specific readiness probe threshold for the Envoy proxy.

```bash
helm install my-release \
  --set envoy.readinessProbe.successThreshold=5 \
    bitnami/contour
```

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

### Coexist with glog

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/k8s.io/klog/v2/README.md

Example demonstrating how to initialize and synchronize flags between klog/v2 and glog. It also shows how to use stderr for combined output by setting alsologtostderr or logtostderr to true.

```go
package main

import (
	"flag"
	"os"

	"k8s.io/klog/v2"
)

func main() {
	// Initialize klog flags
	klog.InitFlags(nil)

	// Initialize glog flags (if used)
	// Note: This is just an example, actual glog flag initialization might differ
	// depending on how glog is integrated.
	// glog.InitFlags(nil)

	// Set alsologtostderr to true to redirect logs to stderr
	flag.Set("alsologtostderr", "true")

	// Parse flags
	flag.Parse()

	// Ensure flags are synced if necessary (e.g., for glog)
	// klog.Flush() // klog flushes automatically on exit, but explicit flush can be used.

	// Example logging
	klog.Info("This is an info message from klog")

	// Ensure logs are written before exiting
	defer klog.Flush()

	// Example of using stderr directly if needed
	os.Stderr.Write([]byte("This is a direct stderr message\n"))
}
```

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

### Deploy Simple App with Kapp

Source: https://github.com/carvel-dev/vendir/blob/develop/examples/http/vendor/k8s-simple-app-digested/k8s-simple-app-example-master/README.md

Deploys the simple application using kapp. Use `kapp inspect` to view the deployment tree and `kapp logs` to follow application logs.

```bash
kapp deploy -a simple-app -f config-step-1-minimal/
kapp inspect -a simple-app --tree
kapp logs -f -a simple-app
```

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

### Install Gonum BLAS Packages

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/gonum.org/v1/gonum/blas/README.md

Use this command to install all Gonum BLAS packages.

```sh
go get gonum.org/v1/gonum/blas/...
```

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

### Install FreePort on Ubuntu/DEB

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/phayes/freeport/README.md

Download and install the FreePort DEB package on Ubuntu and other Debian-based Linux distributions.

```bash
wget wget https://github.com/phayes/freeport/releases/download/1.0.2/freeport_1.0.2_linux_amd64.deb
dpkg -i freeport_1.0.2_linux_amd64.deb
```

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

### Install FreePort on CentOS/RPM

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/phayes/freeport/README.md

Download and install the FreePort RPM package on CentOS and other RPM-based Linux distributions.

```bash
wget https://github.com/phayes/freeport/releases/download/1.0.2/freeport_1.0.2_linux_386.rpm
rpm -Uvh freeport_1.0.2_linux_386.rpm
```

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

### Show Build Commands (Old System)

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/golang.org/x/sys/unix/README.md

Displays the commands that will be run by `mkall.sh` without executing them. Useful for understanding the build process. Requires bash and go.

```bash
mkall.sh -n
```

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

### Install FreePort via Homebrew

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/phayes/freeport/README.md

Install the FreePort utility on macOS using the Homebrew package manager.

```bash
brew install phayes/repo/freeport
```

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

### Install Cobra CLI Generator

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/spf13/cobra/README.md

Install the cobra-cli command line program to generate Cobra application scaffolding.

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

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

### Install Helm

Source: https://github.com/carvel-dev/vendir/blob/develop/examples/image/vendor/docker.io/dkalinin/consul-helm-by-tag/README.md

Installs the Helm package manager using Homebrew. Helm is required for deploying the Consul chart and running tests.

```bash
brew install kubernetes-helm
```

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

### EWMA Usage Example

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/VividCortex/ewma/README.md

Demonstrates how to create and use both SimpleEWMA and VariableEWMA instances. SimpleEWMA is created with no arguments, while VariableEWMA requires an 'age' parameter.

```go
package main

import "github.com/VividCortex/ewma"

func main() {
	samples := [100]float64{
		4599, 5711, 4746, 4621, 5037, 4218, 4925, 4281, 5207, 5203, 5594, 5149,
	}

	e := ewma.NewMovingAverage()  //=> Returns a SimpleEWMA if called without params
	a := ewma.NewMovingAverage(5) //=> returns a VariableEWMA with a decay of 2 / (5 + 1)

	for _, f := range samples {
		e.Add(f)
		a.Add(f)
	}

	e.Value() //=> 13.577404704631077
	a.Value() //=> 1.5806140565521463e-12
}
```

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

### Build All Files (Old System)

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/golang.org/x/sys/unix/README.md

Generates Go files for the current OS and architecture using the old build system. Ensure GOOS and GOARCH are set correctly. Requires bash and go.

```bash
mkall.sh
```

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

### glog Fatal Log Example

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/k8s.io/klog/README.md

Shows how to use glog.Fatalf to log an error message and terminate the program. Use this for critical failures.

```go
glog.Fatalf("Initialization failed: %s", err)
```

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

### Upload Stdin as a Layer to a Local Registry

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/google/go-containerregistry/pkg/v1/stream/README.md

This example demonstrates how to upload the contents of standard input as a layer to a local registry. It uses stream.NewLayer to create a streaming layer from os.Stdin and remote.WriteLayer to upload it.

```go
package main

import (
	"os"

	"github.com/google/go-containerregistry/pkg/name"
	"github.com/google/go-containerregistry/pkg/v1/remote"
	"github.com/google/go-containerregistry/pkg/v1/stream"
)

// upload the contents of stdin as a layer to a local registry
func main() {
	repo, err := name.NewRepository("localhost:5000/stream")
	if err != nil {
		panic(err)
	}

	layer := stream.NewLayer(os.Stdin)

	if err := remote.WriteLayer(repo, layer); err != nil {
		panic(err)
	}
}
```

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

### Build and Sign JWT with HMAC

Source: https://github.com/carvel-dev/vendir/blob/develop/vendor/github.com/form3tech-oss/jwt-go/README.md

Example of building and signing a JWT using HMAC. This demonstrates creating a new token with specific claims and signing it.

```go
package main

import (
	"fmt"
	"github.com/dgrijalva/jwt-go"
	"time"
)

func main() {
	// Create a new token object, specifying the signing method and the claims
	token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
		"name": "John Doe",
		"nbf": time.Now().Unix(),
		"exp": time.Now().Add(time.Hour * 1).Unix(), // Expires in 1 hour
		"iat": time.Now().Unix(),
	})

	// Sign the token with a secret key. 
	tokenString, err := token.SignedString([]byte("your_secret_key"))
	if err != nil {
		panic(err)
	}

	fmt.Println(tokenString)
}
```