How to use Azure App Configuration REST API

Question

Trying to figure out how to use Azure AppConfiguration REST API (mostly to retrieve and create key-values). So far I found two sources of information: Configuration Stores REST API docs and this GitHub repo Azure App Configuration.

How these two sources are corresponding with each other? They apparently describe some different AppConfig REST API.

I managed to retrieve values from my AppConfig store using this type of URI and AAD authorization https://management.azure.com/subscriptions/{subscriptionId}/resourceGroups/{resourceGroupName}/providers/Microsoft.AppConfiguration/configurationStores/{configStoreName}/listKeyValue?api-version=2019-10-01 But it allows to get only one value of one particular key.

The other approach uses URI based on AppConfig endpoint {StoreName}.azconfig.io/kv/... and must have more flexible ways to retrieve data. But I can't make it work. I tried to follow instructions. And I tried to make a request to this URI using AAD token as I did for the first type of API. In both cases I get 401 auth error. Could anyone share some detailed working examples (Powershell, Postman)? Any help would be appreciated.

score 4 · Accepted Answer · answered May 19 '20 at 19:52

4

https://management.azure.com/ is the Azure Resource Management API, while the azconfig.io one is App Configuration's own API.

I think you should use App Configuration's own API. The same Azure AD token will not work for this API however. You need to request another access token with resource=https://yourstorename.azconfig.io or scope=https://yourstorename.azconfig.io/.default, depending if you use v1 or v2 token endpoint of Azure AD.

answered May 19 '20 at 19:52

juunas

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Thank you, @juunas! One short answer and everything fell into place. I wish MS documentation was that clear) – Svetlana May 20 '20 at 07:10

score 0 · Answer 2 · edited Jul 18 '20 at 05:10

Use the $headers in the script to authenticate your api calls:

function Sign-Request(
    [string] $hostname,
    [string] $method,      # GET, PUT, POST, DELETE
    [string] $url,         # path+query
    [string] $body,        # request body
    [string] $credential,  # access key id
    [string] $secret       # access key value (base64 encoded)
)
{  
    $verb = $method.ToUpperInvariant()
    $utcNow = (Get-Date).ToUniversalTime().ToString("R", [Globalization.DateTimeFormatInfo]::InvariantInfo)
    $contentHash = Compute-SHA256Hash $body

    $signedHeaders = "x-ms-date;host;x-ms-content-sha256";  # Semicolon separated header names

    $stringToSign = $verb + "`n" +
                    $url + "`n" +
                    $utcNow + ";" + $hostname + ";" + $contentHash  # Semicolon separated signedHeaders values

    $signature = Compute-HMACSHA256Hash $secret $stringToSign
 
    # Return request headers
    return @{
        "x-ms-date" = $utcNow;
        "x-ms-content-sha256" = $contentHash;
        "Authorization" = "HMAC-SHA256 Credential=" + $credential + "&SignedHeaders=" + $signedHeaders + "&Signature=" + $signature
    }
}

function Compute-SHA256Hash(
    [string] $content
)
{
    $sha256 = [System.Security.Cryptography.SHA256]::Create()
    try {
        return [Convert]::ToBase64String($sha256.ComputeHash([Text.Encoding]::ASCII.GetBytes($content)))
    }
    finally {
        $sha256.Dispose()
    }
}

function Compute-HMACSHA256Hash(
    [string] $secret,      # base64 encoded
    [string] $content
)
{
    $hmac = [System.Security.Cryptography.HMACSHA256]::new([Convert]::FromBase64String($secret))
    try {
        return [Convert]::ToBase64String($hmac.ComputeHash([Text.Encoding]::ASCII.GetBytes($content)))
    }
    finally {
        $hmac.Dispose()
    }
}

# Stop if any error occurs
$ErrorActionPreference = "Stop"

$uri = [System.Uri]::new("https://{myconfig}.azconfig.io/kv?api-version=1.0")
$method = "GET"
$body = $null
$credential = "<Credential>"
$secret = "<Secret>"

$headers = Sign-Request $uri.Authority $method $uri.PathAndQuery $body $credential $secret

Sauce: https://github.com/Azure/AppConfiguration/blob/master/docs/REST/authentication/hmac.md#JavaScript

How to use Azure App Configuration REST API

2 Answers2

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