You are working on a monitoring system for a Kubernetes cluster. As part of this system, you need to implement a function that constructs a client configuration for a lister and another function that constructs a Kubernetes client configuration for the kubelet.

Here is the code snippet you need to work with:

```go
if err != nil {
    return nil, fmt.Errorf("unable to construct lister client config: %v", err)
}
return clientConfig, err
}

func (o Options) kubeletConfig(restConfig *rest.Config) *scraper.KubeletClientConfig {
    kubeletRestCfg := rest.CopyConfig(restConfig)
    if len(o.KubeletCAFile) > 0 {
        kubeletRestCfg.TLSClientConfig.CAFile = o.KubeletCAFile
        kubeletRestCfg.TLSClientConfig.CAData = nil
    }
    return scraper.GetKubeletConfig(kubeletRestCfg, o.KubeletPort, o.KubeletUseNodeStatusPort, o.InsecureKubeletTLS, o.DeprecatedCompletelyInsecureKubelet)
}
```

You need to complete the following tasks:

1. Implement the `constructListerClientConfig` function that takes an error `err` and a `clientConfig` and returns an error `err`. This function should check if the `err` is not `nil`. If it is not `nil`, the function should construct an error message in the format: "unable to construct lister client config: <err>" and return it. Otherwise, it should return `clientConfig` and `err` as-is.

2. Implement the `kubeletConfig` method of the `Options` struct. The method takes a `restConfig` and returns a `*scraper.KubeletClientConfig`. Inside the method, create a copy of the `restConfig` using `rest.CopyConfig`. Then, check if the `o.KubeletCAFile` is a non-empty string. If it is, update the `CAFile` field of the `TLSClientConfig` in the copied config to `o.KubeletCAFile` and set the `CAData` field to `nil`. Finally, call `scraper.GetKubeletConfig` with the updated config, along with other `Options` fields: `o.KubeletPort`, `o.KubeletUseNodeStatusPort`, `o.InsecureKubeletTLS`, `o.DeprecatedCompletelyInsecureKubelet`, and return the result.

Note: You can assume that all the required packages are properly imported and provided to your code.

Complete the given tasks by writing the code in the provided spaces.
user
Sure, I can help you with that. Here's how you can implement the functions in Go:

1. **constructListerClientConfig** function:

```go
func constructListerClientConfig(err error, clientConfig *rest.Config) (*rest.Config, error) {
    // If there's an error, return the error before the clientConfig
    if err != nil {
        return nil, fmt.Errorf("unable to construct lister client config: %v", err)
    }
    // Otherwise, return the clientConfig as-is
    return clientConfig, err
}
```

2. **kubeletConfig** method with `Options` struct:

```go
type Options struct {
    KubeletCAFile string
    KubeletPort    int
    UseNodeStatusPort bool
    InsecureKubeletTLS bool
    CompletelyInsecureKubelet bool
}

func (o Options) kubeletConfig(restConfig *rest.Config) *scraper.KubeletClientConfig {
    // Make a copy of the restConfig
    kubeletRestCfg := rest.CopyConfig(restConfig)

    // If KubeletCAFile is non-empty, update the CA and set CAData to nil
    if len(o.KubeletCAFile) > 0 {
        kubeletRestCfg.TLSClientConfig.CAFile = o.KubeletCAFile
        kubeletRestCfg.TLSClientConfig.CAData = nil
    }

    // Get the Kubelet Client Config
    return scraper.GetKubeletConfig(kubeletRestCfg, o.KubeletPort, o.UseNodeStatusPort, o.InsecureKubeletTLS, o.CompletelyInsecureKubelet)
}
```

Note: The `rest` package should be imported for the `rest.CopyConfig` function. Also, for `scraper.GetKubeletConfig`, please ensure that the `scraper` package is imported correctly in the project.
assistant
You are working on a monitoring system for a Kubernetes cluster. As part of this system, you need to implement a function that constructs a client configuration for a lister and another function that constructs a Kubernetes client configuration for the kubelet.

Here is the code snippet you need to work with:

```go
if err != nil {
    return nil, fmt.Errorf("unable to construct lister client config: %v", err)
}
return clientConfig, err
}

func (o Options) kubeletConfig(restConfig *rest.Config) *scraper.KubeletClientConfig {
    kubeletRestCfg := rest.CopyConfig(restConfig)
    if len(o.KubeletCAFile) > 0 {
        kubeletRestCfg.TLSClientConfig.CAFile = o.KubeletCAFile
        kubeletRestCfg.TLSClientConfig.CAData = nil
    }
    return scraper.GetKubeletConfig(kubeletRestCfg, o.KubeletPort, o.KubeletUseNodeStatusPort, o.InsecureKubeletTLS, o.DeprecatedCompletelyInsecureKubelet)
}
```

You need to complete the following tasks:

1. Implement the `constructListerClientConfig` function that takes an error `err` and a `clientConfig` and returns an error `err`. This function should check if the `err` is not `nil`. If it is not `nil`, the function should construct an error message in the format: "unable to construct lister client config: <err>" and return it. Otherwise, it should return `clientConfig` and `err` as-is.

2. Implement the `kubeletConfig` method of the `Options` struct. The method takes a `restConfig` and returns a `*scraper.KubeletClientConfig`. Inside the method, create a copy of the `restConfig` using `rest.CopyConfig`. Then, check if the `o.KubeletCAFile` is a non-empty string. If it is, update the `CAFile` field of the `TLSClientConfig` in the copied config to `o.KubeletCAFile` and set the `CAData` field to `nil`. Finally, call `scraper.GetKubeletConfig` with the updated config, along with other `Options` fields: `o.KubeletPort`, `o.KubeletUseNodeStatusPort`, `o.InsecureKubeletTLS`, `o.DeprecatedCompletelyInsecureKubelet`, and return the result.

Note: You can assume that all the required packages are properly imported and provided to your code.

Complete the given tasks by writing the code in the provided spaces.
user
Sure, here is the completed code for the given tasks:

```go
// Task 1: Implement the constructListerClientConfig function
func constructListerClientConfig(err error, clientConfig *rest.Config) (*rest.Config, error) {
    if err != nil {
        return nil, fmt.Errorf("unable to construct lister client config: %v", err)
    }
    return clientConfig, nil
}

// Task 2: Implement the kubeletConfig method of the Options struct
type Options struct {
    KubeletCAFile                      string
    KubeletPort                        int
    KubeletUseNodeStatusPort           bool
    InsecureKubeletTLS                 bool
    DeprecatedCompletelyInsecureKubelet bool
}

func (o Options) kubeletConfig(restConfig *rest.Config) *scraper.KubeletClientConfig {
    kubeletRestCfg := rest.CopyConfig(restConfig)
    if len(o.KubeletCAFile) > 0 {
        kubeletRestCfg.TLSClientConfig.CAFile = o.KubeletCAFile
        kubeletRestCfg.TLSClientConfig.CAData = nil
    }
    return scraper.GetKubeletConfig(kubeletRestCfg, o.KubeletPort, o.KubeletUseNodeStatusPort, o.InsecureKubeletTLS, o.DeprecatedCompletelyInsecureKubelet)
}
```
assistant