Azure CLI Exception Handling

Question

I have installed the azure cli on my local system and I am able to run the azure cli commands in Windows Powershell. When I run any command which is not correct or throwing any exception, I am able to see it on the console. But how can I capture this exception using Try...Catch . I want to handle the exception using try..catch in powershell script.

Please help me on this.

code snippet:

Suppose my ClientSecret is wrong then the below command will through an exception, how can I capture this in Catch block??

 Try
    {

     $TenantId = 'xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx' 
     $ClientId = 'xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx' 
     $ClientSecret = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx'

     az login --service-principal -u $ClientId -p $ClientSecret --tenant $TenantId 

    }
    Catch 
    {
        $ErrorMessage = $_.Exception.Message
        Write-Output $ErrorMessage 
    }

this is the snapshot of the issue

Answer 1

More recent versions of the CLI support a global parameter --only-show-errors which will suppress preview messages. So you could amend the Avshalom answer like this to solve the issue UNeverNo raised:

if (az login --service-principal -u $ClientId -p $ClientSecret --tenant $TenantId --only-show-errors)
{
   "Success"
}
else {"Error"}

Answer 2

Answering that late to help others facing the same issue. Try to store the output in a parameter and check if it is null or not. As azure commands give the output in json format, we can use:

$output = az login -u "username" -p "password" | ConvertFrom-Json
if (!$output) {
    Write-Error "Error validating the credentials"
    return
}

Answer 3

In regular Powershell commands you can use the CommonParameter -ErrorAction Stop But for the AzureCli az command i think you can use a simple if statement:

if (az login --service-principal -u $ClientId -p $ClientSecret --tenant $TenantId)
{
   "Success"
}
     else {"Error"}

Or check the last exit state using the $? Automatic variable after the login attempt:

if (!$?) {"Error"}

Answer 4

Try using the --query operator to check for things you need. For example, Avshalom's answer might be correct if you query for state enabled or something. I am doing similar things in some places:

# Create the Web App if it does not already exist
if(-Not (az webapp show --name $webAppName --resource-group $resourceGroupName))
{
    az webapp create --name $webAppName --resource-group $resourceGroupName --plan $servicePlanName --tags 'displayName=WebApp'
}

Answer 5

I had a requirement to check if a particular Apim Api Version Set exists or not, for which there are no standard "exists" commands available. Below is how I managed to get the result.

$result = az apim api versionset list --resource-group MyResourceGroup --service-name MyApim --query "[?name=='MyVersionSet']" | ConvertFrom-Json

$exists = $result.Length -gt 0

$exists will return true if the version set exists.

Answer 6

So I could capture the correct error from Az Cli, and to avoid having to add an extra line for each az command, I created my own az-ps function to wrap all az calls:

function az-ps {
    $result = az $args 2>&1
    if(!$?) { Write-Error -Message "az $args returned error $result" -ErrorAction Stop }
    return $result
}

Then I just called this instead of az - e.g.:

$databases = az-ps sql midb list --resource-group myResourceGroup --managed-instance myManagedSqlInstance

If this returns an error you get:

Write-Error: az_error_test.ps1:11
Line |
  11 |  … databases = az-ps sql midb list --resource-group myResourceGroup  --manage …
     |                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     | az sql midb list --resource-group myResourceGroup --managed-instance
     | myManagedSqlInstance returned error ERROR: (ParentResourceNotFound) Can not perform requested operation
     | on nested resource. Parent resource 'myManagedSqlInstance' not found. Code: ParentResourceNotFound
     | Message: Can not perform requested operation on nested resource. Parent resource 'myManagedSqlInstance'
     | not found.

What this does:

It passes all the $args to az so it should accept any args that az does

The 2>&1 param means that the Error output (2) will get redirected to the normal output (1) - so $result will contain the output of the az call if it is successful, or the error message if it fails.

$? is a special powershell var the contains true if the last command succeeded of false if it fails

-ErrorAction Stop will prevent the powershell script from continuing (unless there is a try/catch block)