💾 Storing files in GreenCloud

How does it work?

GreenCloud allows you to create a storage function where you can store files up to 1mb in size.

GreenCloud ensures your files are private by masking important information. Files are broken down across multiple server nodes to ensure security.

Creating a storage function

1. Use the gccli command

gccli fx init

Example

$ gccli fx init  
🔑 Obtaining accessToken...
👷 Validating inputs...
🥼 Name → storageTests
🔖 Language → go
👔 Description → Creating test storage
⌚ Timeout → 10
📡 Sharing information...
📄 Copying template...
📝 Saving configuration...
🌱 Function created successfully!

2. Open your created function.

Example

package function

import (
    "net/http"

    handler "github.com/openfaas/templates-sdk/go-http"
)

// Handle a function invocation
func Handle(req handler.Request) (handler.Response, error) {
    var err error

    body := req.Body
    headers := http.Header{
        "Content-Type": []string{req.Header.Get("Content-Type")},
    }

    if len(body) == 0 {
        body = []byte("Hello from GO by GreenCloud!")
        headers.Set("Content-Type", "text/plain; charset=utf-8")
    }

    return handler.Response{
        Body:       body,
        StatusCode: http.StatusOK,
        Header:     headers,
    }, err
}

3. Write your code to create storage and then store your information within.

Example

Text

package function

import (
    "encoding/base64"
    "net/http"

    handler "github.com/openfaas/templates-sdk/go-http"
)

func Handle(req handler.Request) (handler.Response, error) {
    // set headers
    headers := http.Header{}
    headers.Set("Content-Type", "text/plain")

    // get storage
    storage := req.Header.Get("GC-Storage")
    body, err := base64.StdEncoding.DecodeString(storage)
    if err != nil || len(body) == 0 {
        // set storage
        newStorage := base64.StdEncoding.EncodeToString([]byte("I am a storage Test!"))
        headers.Set("GC-Storage", newStorage)

        // if no storage is found, return default text
        return handler.Response{
            Body:       []byte("No storage found"),
            StatusCode: http.StatusNotFound,
            Header:     headers,
        }, nil
    }

    return handler.Response{
        Body:       body,
        StatusCode: http.StatusOK,
        Header:     headers,
    }, nil
}

JSON

package function

import (
    "encoding/base64"
    "encoding/json"
    "net/http"

    handler "github.com/openfaas/templates-sdk/go-http"
)

func Handle(req handler.Request) (handler.Response, error) {
    var body []byte

    // set headers
    headers := http.Header{}

    // get storage
    storage := req.Header.Get("GC-Storage")
    text, err := base64.StdEncoding.DecodeString(storage)
    if err != nil || len(text) == 0 {
        // set storage
        jsonStorage, _ := json.Marshal(map[string]interface{}{"user": "root", "password": "root"})
        newStorage := base64.StdEncoding.EncodeToString(jsonStorage)
        headers.Set("GC-Storage", newStorage)

        // if no storage is found, return default text
        headers.Set("Content-Type", "text/plain")
        return handler.Response{
            Body:       []byte("No storage found"),
            StatusCode: http.StatusNotFound,
            Header:     headers,
        }, nil
    } else {
        var jsonObject map[string]interface{}
        if err := json.Unmarshal(text, &jsonObject); err == nil {
            jsonObject, err := json.Marshal(jsonObject)
            if err == nil {
                body = jsonObject
                headers.Set("Content-Type", "application/json")
            }
        }
    }

    return handler.Response{
        Body:       body,
        StatusCode: http.StatusOK,
        Header:     headers,
    }, nil
}

image/png

package function

import (
    "embed"
    "encoding/base64"
    "net/http"

    handler "github.com/openfaas/templates-sdk/go-http"
)

//go:embed img
var images embed.FS

func Handle(req handler.Request) (handler.Response, error) {
    var body []byte

    // set headers
    headers := http.Header{}
    headers.Set("Content-Type", "text/plain")

    // Get Storage
    storage := req.Header.Get("GC-Storage")
    imgInStorage, err := base64.StdEncoding.DecodeString(storage)
    if err != nil || len(imgInStorage) == 0 {
        // read image file from disk
        imgToStore, err := images.ReadFile("img/gc-centered.png")
        if err != nil {
            return handler.Response{
                Body:       []byte(err.Error()),
                StatusCode: http.StatusInternalServerError,
                Header:     headers,
            }, nil
        }

        // set Storage
        newStorage := base64.StdEncoding.EncodeToString(imgToStore)
        headers.Set("GC-Storage", newStorage)

        // if no storage is found, return default text
        return handler.Response{
            Body:       []byte("No storage found"),
            StatusCode: http.StatusNotFound,
            Header:     headers,
        }, nil
    } else {
        // if storage is found, return the image
        body = imgInStorage
        headers.Set("Content-Type", "image/png")
    }

    return handler.Response{
        Body:       body,
        StatusCode: http.StatusOK,
        Header:     headers,
    }, nil
}

4. Deploy your code to GreenCloud

 $ gccli fx deploy
👷 Verifying configuration...
📦️ Archs: AMD64
⏳️ Process may take a while, please wait...
🧩 Compiling multi-arch image [OK]                              
🚚 Pushing image to registry...
🔥 Function successfully uploaded!

5. Create a public endpoint URL.

 $ gccli fx public
👷 Validating inputs...
🚨 You must keep the public endpoint safe!
✋ Do you wish to continue? (y/n) → y
🤖 Public endpoint created successfully!
🔗 https://api.greencloud.dev/gc/6655ff265b7bb1846afb0f6a

6. Access your public endpoint using the link provided.

Example

https://api.greencloud.dev/gc/6655ff265b7bb1846afb0f6a

⏳ Your function is queued up and will be executed in due time.

The result will be available for the next 5 minutes at the link below.

https://api.greencloud.dev/gc/6656ef17f9440e67ae781692/result

7. Follow the result link to retrieve your result.

Example

Text

https://api.greencloud.dev/gc/6656ef17f9440e67ae781692/result

I am a storage Test!

JSON

https://api.greencloud.dev/gc/6656ef17f9440e67ae781692/result

{
    "password": "root",
    "user": "root"
}

image/png

https://api.greencloud.dev/gc/6656ef17f9440e67ae781692/result

8. Make sure to delete the endpoint when it is no longer needed.

Example

 $ gccli function public --id 6655ff265b7bb1846afb0f6a --delete
🔑 Obtaining accessToken...
👷 Validating inputs...
🔖 ID → 6655ff265b7bb1846afb0f6a
🔥 Public endpoint deleted successfully!