azblobretriever

README

Azure Blob Storage Feature Flag Retriever

This retriever is used to retrieve data from a Container on Azure Blob Storage.

Installation

go get github.com/thomaspoignant/go-feature-flag/retriever/azblobstorageretriever

Usage

Configuration

Create a Retriever struct with the following fields:

• Container: Name of the Azure Blob Storage container
• AccountName: Azure Storage Account Name
• AccountKey: (Optional) Storage Account Key
• ServiceURL: (Optional) Custom service URL
• Object: Name of the feature flag file in the container

Authentication Methods

1. Shared Key Authentication

retriever := &azblobretriever.Retriever{
    Container:    "your-container",
    AccountName:  "your-account-name",
    AccountKey:   "your-account-key",
    Object:       "feature-flags.json",
}

2. Microsoft Entra ID (Recommended)

retriever := &azblobretriever.Retriever{
    Container:    "your-container",
    AccountName:  "your-account-name",
    Object:       "feature-flags.json",
}

Retrieving Feature Flags

package main

import (
    "context"
    "fmt"
    "log"
    "time"

    "github.com/thomaspoignant/go-feature-flag/retriever/azblobstorageretriever"
)

func main() {
    retriever := &azblobretriever.Retriever{
        Container:   "feature-flags",
        AccountName: "mystorageaccount",
        AccountKey:  "your-account-key",
        Object:      "flags.json",
    }

    ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
    defer cancel()

    err := retriever.Init(ctx, nil)
    defer func() { _ = r.Shutdown(ctx) }()
    if err != nil {
        log.Fatalf("Failed to initialize retriever:", err)
    }

    data, err := retriever.Retrieve(ctx)
    if err != nil {
        log.Fatalf("Failed to retrieve feature flags: %v", err)
    }

    fmt.Println("Retrieved feature flags:")
    fmt.Println(string(data))
}

Key Features

• Supports both shared key and default Azure credential authentication
• Automatic retry mechanism for blob downloads
• Flexible configuration with optional custom service URL

Error Handling

The Retrieve method returns an error if:

• AccountName is empty
• Container or Object is not specified
• There's an issue initializing the Azure client.
• There's a problem downloading or reading the file from Azure Blob Storage.

Best Practices

• Security Never hard-code your AccountKey in your source code. Use environment variables or a secure secret management system.
• Error Handling: Always check for errors returned by the Retrieve method.
• Context: Use a context with timeout for better control over the retrieval process.

Documentation

Index

• type Retriever
  • func (r *Retriever) Init(_ context.Context, _ *fflog.FFLogger) error
  • func (r *Retriever) Retrieve(ctx context.Context) ([]byte, error)
  • func (r *Retriever) Shutdown(_ context.Context) error
  • func (r *Retriever) Status() retriever.Status

Types

type Retriever

type Retriever struct {
	// Container is the name of your Azure Blob Storage Container.
	Container string

	// Storage Account Name and Key
	AccountName string
	AccountKey  string

	// ServiceURL is the URL of the storage account e.g. https://<account>.blob.core.windows.net/
	// It can be overridden by the user to use a custom URL.
	// Default: https://<account>.blob.core.windows.net/
	ServiceURL string

	// Object is the name of your file in your container.
	Object string
	// contains filtered or unexported fields
}

func (*Retriever) Init

func (r *Retriever) Init(_ context.Context, _ *fflog.FFLogger) error

func (*Retriever) Retrieve

func (r *Retriever) Retrieve(ctx context.Context) ([]byte, error)

func (*Retriever) Shutdown

func (r *Retriever) Shutdown(_ context.Context) error

func (*Retriever) Status

func (r *Retriever) Status() retriever.Status