Multiple cloud-sql table export as csv - google-cloud-platform

Question

Is there a way to export multiple SQL tables as csv by issuing specific queries from cloud-sql.
Below is the code i currently have. When I call the exportTables for multiple tables back to back, I see a 409 error. It's probably becaause cloud-sql instance is busy with an export and it's not allowing subsequent export request.
How can I get this to work ? What would be the ideal solution here.
private void exportTables(String table_name, String query)
throws IOException, InterruptedException {
HttpClient httpclient = new HttpClient();
PostMethod httppost =
new PostMethod(
"https://www.googleapis.com/sql/v1beta4/projects/"
+ "abc"
+ "/instances/"
+ "zxy"
+ "/export");
String destination_bucket =
String.join(
"/",
"gs://" + "test",
table_name,
DateTimeUtil.getCurrentDate() + ".csv");
GoogleCredentials credentials =
GoogleCredentials.getApplicationDefault().createScoped(SQLAdminScopes.all());
AccessToken access_token = credentials.refreshAccessToken();
access_token.getTokenValue();
httppost.addRequestHeader("Content-Type", "application/json");
httppost.addRequestHeader("Authorization", "Bearer " + access_token.getTokenValue());
String request =
"{"
+ " \"exportContext\": {"
+ " \"fileType\": \"CSV\","
+ " \"uri\":\""
+ destination_bucket
+ "\","
+ " \"databases\": [\""
+ "xyz"
+ "\"],"
+ " \"csvExportOptions\": {"
+ " \"selectQuery\": \""
+ query
+ "\""
+ " }\n"
+ " }"
+ "}";
httppost.setRequestEntity(new StringRequestEntity(request, "application/json", "UTF-8"));
httpclient.executeMethod(httppost);
if (httppost.getStatusCode() > 200) {
String response = new String(httppost.getResponseBody(), StandardCharsets.UTF_8);
if (httppost.getStatusCode() != 409) {
throw new RuntimeException(
"Exception occurred while exporting the table: " + table_name + " Error " + response);
} else {
throw new IOException("SQL instance seems to be busy at the moment. Please retry");
}
}
httppost.releaseConnection();
logger.info("Finished exporting table {} to {}", table_name, destination_bucket);
}

Answer 1

I don't have suggestion to fix the issue on Cloud SQL directly, but a solution to execute in sequence the export thanks to a new tool: Workflow
Define the data format that you want, in JSON, to define ONE export.
Then provide an array of configuration to your workflow
In this workflow,
Make a loops on the configuration array
Perform an API call to Cloud SQL to generate the export on each configuration
Get the answer of the API Call, you have the jobId
Sleep a while
Check if the export is over (with the jobId).
If not, sleep and check again
If yes, loop (and thus start the next export)
It's serverless and the free tier makes this use case free.