PowerShell Scripting to Replicate Google Spanner Data to MySQL

The CData Cmdlets for Google Spanner offer live access to Google Spanner data from within PowerShell. Using PowerShell scripts, you can easily automate regular tasks like data replication. This article will walk through using the CData Cmdlets for Google Spanner and the CData Cmdlets for MySQL in PowerShell to replicate Google Spanner data to a MySQL database.

After obtaining the needed connection properties, accessing Google Spanner data in PowerShell and preparing for replication consists of four basic steps.

Google Spanner uses the OAuth authentication standard. To authenticate using OAuth, you can use the embedded credentials or register an app with Google.

See the Getting Started guide in the CData driver documentation for more information.

Collecting Google Spanner Data

1. Install the module:

   Install-Module GoogleSpannerCmdlets

2. Connect to Google Spanner:

    $googlespanner = Connect-GoogleSpanner -ProjectId $ProjectId -InstanceId $InstanceId -Database $Database -InitiateOAuth $InitiateOAuth
    

3. Retrieve the data from a specific resource:

    $data = Select-GoogleSpanner -Connection $googlespanner -Table "Customer"
    

   You can also use the Invoke-GoogleSpanner cmdlet to execute pure SQL-92 statements:

    $data = Invoke-GoogleSpanner -Connection $googlespanner -Query 'SELECT * FROM Customer WHERE Id = @Id' -Params @{'@Id'='1'}
    

4. Save a list of the column names from the returned data.

    $columns = ($data | Get-Member -MemberType NoteProperty | Select-Object -Property Name).Name
    

Inserting Google Spanner Data into the MySQL Database

With the data and column names collected, you are ready to replicate the data into a MySQL database.

1. Install the module:

   Install-Module MySQLCmdlets

2. Connect to MySQL, using the server address and port of the MySQL server, valid user credentials, and a specific database with the table in which the data will be replicated:

    $mysql = Connect-MySQL -User $User -Password $Password -Database $Database -Server $Server -Port $Port
    

3. Loop through the Google Spanner data, store the values, and use the Add-MySQL cmdlet to insert the data into the MySQL database, one row at a time. In this example, the table will need to have the same name as the Google Spanner resource (Customer) and to exist in the database.

    $data | % {
    $row = $_
    $values = @()
    $columns | % {
    $col = $_
    $values += $row.$($col)
    }
    Add-MySQL -Connection $mysql -Table "Customer" -Columns $columns -Values $values
    }
    

You have now replicated your Google Spanner data to a MySQL database. This gives you freedom to work with Google Spanner data in the same way that you work with other MySQL tables, whether that is performing analytics, building reports, or other business functions.

Notes

• Once you have connected to Google Spanner and MySQL in PowerShell, you can pipe command results to perform the replication in a single line:

   Select-GoogleSpanner -Connection $googlespanner -Table "Customer" | % {
   $row = $_
   $values = @()
   $columns | % {
   $col = $_
   $values += $row.$($col)
   }
   Add-MySQL -Connection $mysql -Table "Customer" -Columns $columns -Values $values
   }
   

• If you wish to replicate the Google Spanner data to another database using another PowerShell module, you will want to exclude the Columns, Connection, and Table columns from the data returned by the Select-GoogleSpanner cmdlet since those columns are used to help pipe data from one CData cmdlet to another:

   $columns = ($data | Get-Member -MemberType NoteProperty | Select-Object -Property Name).Name | ? {$_ -NotIn @('Columns','Connection','Table')}