Introduction to AzureRMR

Hong Ooi

AzureRMR is a package for interacting with Azure Resource Manager: authenticate, list subscriptions, manage resource groups, deploy and delete templates and resources. It calls the Resource Manager REST API directly, so you don’t need to have PowerShell or Python installed.

As a general-purpose interface to Azure Resource Manager (ARM), you can use AzureRMR to work with nearly any Azure object that ARM can handle: subscriptions, resource groups, resources, templates and so on. The things you can do include:

Authentication

Under the hood, AzureRMR uses a similar authentication process to the Azure CLI. The first time you authenticate with a given Azure Active Directory tenant, you call create_azure_login(), which will log you into Azure. AzureRMR will prompt you for permission to create a special data directory in which to cache your credentials. Once this information is saved on your machine, it can be retrieved in subsequent R sessions with get_azure_login(). Your credentials will be automatically refreshed so you don’t have to reauthenticate.

Unless you have a good reason otherwise, you should allow AzureRMR to create this caching directory. Note that many other cloud engineering tools save credentials in this way, including the Azure CLI itself. You can see what directory AzureRMR has created with the function AzureR_dir().

library(AzureRMR)
#> AzureRMR can cache Azure Active Directory tokens and Resource Manager logins in the directory:
#>
#> C:\Users\hongooi\AppData\Local\AzureR\AzureRMR
#>
#> This saves you having to reauthenticate with Azure in future sessions. Create this directory? (Y/n) y

AzureR_dir()
#> [1] "C:\\Users\\hongooi\\AppData\\Local\\AzureR"


# if this is the first time you're logging in
az <- create_azure_login()
#> Creating Azure Resource Manager login for default tenant
#> Waiting for authentication in browser...
#> Press Esc/Ctrl + C to abort
#> Authentication complete.


# for subsequent sessions
az <- get_azure_login()
#> Loading Azure Resource Manager login for default tenant


# you can also list the tenants that you've previously authenticated with
list_azure_logins()

Service principal

Authenticating with Azure Active Directory requires providing an app or service principal ID. If you don’t provide one, AzureRMR will authenticate using the Azure CLI cross-platform app. This is usually sufficient for most purposes, however if possible it’s recommended that you create your own service principal to authenticate with. For example, if security is a concern, this lets you restrict the scope of the resources that AzureRMR that manipulate.

Creating a service principal is a one-time task, and the easiest method is to use the Azure cloud shell.

If you want to allow access at something other than subscription level, you can use the --scopes argument in place of --subscription. For example, to restrict AzureRMR to only the “AnalyticsRG” resource group: az ad sp create-for-rbac --scopes /subscriptions/{your-subscription-ID}/resourceGroups/AnalyticsRG.

Once you have created your own service principal, you can supply the app ID and password as arguments to create_azure_login. You’ll also have to supply your Azure Active Directory tenant, as AAD does not have access to your personal credentials.

# authenticating with a custom service principal
create_azure_login(tenant="myaadtenant", app="app_id", password="password")

Subscriptions and resource groups

AzureRMR allows you to work with your subscriptions and resource groups. Note that if you created your service principal via the cloud shell, as described in this vignette, you probably only have access to one subscription. Regardless, you can list all subscriptions that you can work with:

# all subscriptions
az$list_subscriptions()
#> $`5710aa44-281f-49fe-bfa6-69e66bb55b11`
#> <Azure subscription 5710aa44-281f-49fe-bfa6-69e66bb55b11>
#>   authorization_source: RoleBased
#>   name: Visual Studio Ultimate with MSDN
#>   policies: list(locationPlacementId, quotaId, spendingLimit)
#>   state: Enabled
#> ---
#>   Methods:
#>     create_resource_group, delete_resource_group, get_provider_api_version, get_resource_group,
#>     list_locations, list_resource_groups, list_resources
#> 
#> $`e26f4a80-370f-4a77-88df-5a8d291cd2f9`
#> <Azure subscription e26f4a80-370f-4a77-88df-5a8d291cd2f9>
#>   authorization_source: RoleBased
#>   name: ADLTrainingMS
#>   policies: list(locationPlacementId, quotaId, spendingLimit)
#>   state: Enabled
#> ---
#>   Methods:
#>     create_resource_group, delete_resource_group, get_provider_api_version, get_resource_group,
#>     list_locations, list_resource_groups, list_resources
#> 
#> ...

Notice that AzureRMR is based on R6 classes, where methods are part of the object itself (much like objects in C++, C# and Java). Thus list_subscriptions is a member of the az object, and we call it with az$list_subscriptions(). R6 is used because it allows objects to have persistent state; in this case, the objects in R represent corresponding objects in Azure.

The list_subscriptions() call returns a list of subscription objects. You can retrieve the details for a single subscription with get_subscription:

# get a subscription
(sub1 <- az$get_subscription("5710aa44-281f-49fe-bfa6-69e66bb55b11"))
#> <Azure subscription 5710aa44-281f-49fe-bfa6-69e66bb55b11>
#>   authorization_source: Legacy
#>   name: Visual Studio Ultimate with MSDN
#>   policies: list(locationPlacementId, quotaId, spendingLimit)
#>   state: Enabled
#> ---
#>   Methods:
#>     create_resource_group, delete_resource_group, get_provider_api_version, get_resource_group,
#>     list_locations, list_resource_groups, list_resources

A subscription object in turn has methods to get, create and delete resource groups (and also list all resource groups):

(rg <- sub1$get_resource_group("rdev1"))
#> <Azure resource group rdev1>
#>   id: /subscriptions/5710aa44-281f-49fe-bfa6-69e66bb55b11/resourceGroups/rdev1
#>   location: australiaeast
#>   properties: list(provisioningState)
#> ---
#>   Methods:
#>     check, create_resource, delete, delete_resource, delete_template, deploy_template, get_resource,
#>     get_template, list_resources, list_templates

# create and delete a resource group
test <- sub1$create_resource_group("test_group")
test$delete(confirm=FALSE)

Resources and templates

Methods for working with resources and templates are exposed as part of the az_resource_group class. You can retrieve an existing resource/template, create a new one, or delete an existing one.

(stor <- rg$get_resource(type="Microsoft.Storage/storageServices", name="rdevstor1"))
#> <Azure resource Microsoft.Storage/storageAccounts/rdevstor1>
#>   id: /subscriptions/5710aa44-281f-49fe-bfa6-69e66bb55b11/resourceGroups/rdev1/providers/Microsoft.Sto ...
#>   is_synced: TRUE
#>   kind: Storage
#>   location: australiasoutheast
#>   properties: list(networkAcls, trustedDirectories, supportsHttpsTrafficOnly, encryption,
#>     provisioningState, creationTime, primaryEndpoints, primaryLocation, statusOfPrimary)
#>   sku: list(name, tier)
#>   tags: list()
#> ---
#>   Methods:
#>     check, delete, do_operation, set_api_version, sync_fields, update

One benefit of the syntax that AzureRMR uses is that method chaining works. This is the OOP version of pipelines, which most R users will recognise from the tidyverse.

# use method chaining to get a resource without creating a bunch of intermediaries
# same result as above
stor <- az$
    get_subscription("5710aa44-281f-49fe-bfa6-69e66bb55b11")$
    get_resource_group("rdev1")$
    get_resource(type="Microsoft.Storage/storageServices", name="rdevstor1")

Once we have a resource, we can do things with it, via the do_operation() method. In this case, we have a storage account. One of the things we can do with a storage account is retrieve its access keys:

stor$do_operation("listKeys", http_verb="POST")
#>  $`keys`
#>  $`keys`[[1]]
#>  $`keys`[[1]]$`keyName`
#>  [1] "key1"
#>  
#>  $`keys`[[1]]$value
#>  [1] "k0gGFi8LirKcDNe73fzwDzhZ2+4oRKzvz+6+Pfn2ZCKO/JLnpyBSpVO7btLxBXQj+j8MZatDTGZ2NXUItye/vA=="
#>  
#>  $`keys`[[1]]$permissions
#>  [1] "FULL"
#> ...

Here is another example. If we have a virtual machine, we can start it, execute shell commands, and then shut it down again:

vm <- rg$get_resource(type="Microsoft.Compute/virtualMachines",
    name="myVirtualMachine")

vm$do_operation("start", http_verb="POST") # may take a while
vm$do_operation("runCommand",
    body=list(
        commandId="RunShellScript", # RunPowerShellScript for Windows
        script=as.list("ifconfig > /tmp/ifconfig.out")
    ),
    encode="json",
    http_verb="POST")
vm$do_operation("powerOff", http_verb="POST")

For the types of operations you can carry out on a resource, consult the Azure REST API documentation.

You can also interrogate the fields of a resource object; in particular the properties field can contain arbitrary information about an Azure resource. For example, a storage account’s properties includes the endpoint URIs, and a virtual machine’s properties includes its admin login details.

# file and blob storage endpoint
stor$properties$primaryEndpoints$file
stor$properties$primaryEndpoints$blob

# OS profile for a VM: includes login details
vm$properties$osProfile

In a manner similar to resources, deploying a template is just a matter of calling the resource group object’s deploy_template method. This takes two arguments, template and parameters. Both arguments should be in JSON format: either the name of a JSON file, a character vector containing the JSON data, or a list containing the parsed JSON (via jsonlite::toJSON).

vm_tpl <- rg$deploy_template("myNewVirtualMachine",
    template="vm_template.json",
    parameters=list(
        os="Linux",
        size="Standard_DS2_v2",
        username="ruser",
        publickey=readLines("~/id_rsa.pub")
    ))

Normally, deleting a template doesn’t touch the resources it creates: it only deletes the template itself. However, AzureRMR optionally allows you to free any resources created when you delete a template. This is useful when managing complex objects like VMs, which actually consist of multiple individual resources in Azure (storage account, disk, network interface, etc). When you are done with the VM, deleting the template lets you free all these resources with a single command.

vm_tpl$delete(free_resources=TRUE)

Conclusion

This has been a quick introduction to the features of AzureRMR. Remember that this package is only meant to be a generic mechanism for working with Resource Manager. You can extend it to provide support for service-specific features; examples of packages that do this include AzureVM for virtual machines, and AzureStor for storage accounts. For more information, see the “Extending AzureRMR” vignette.