问题
I am using nodejs to contact the google datastore. This is my code:
dataset.runInTransaction(function(transaction, done,err) {
// From the `transaction` object, execute dataset methods as usual.
// Call `done` when you're ready to commit all of the changes.
transaction.save(entities, function(err) {
if(err){
console.log("ERROR TRNASCTION");
transaction.rollback(done);
return;
}else{
console.log("TRANSACTION SUCCESS!");
done();
}
});
});
If the save was not successful, I would like the transaction to rollback and if it was I want it to commit. The problem I am facing is that neither of them seem to be running, just no output on the console. Nothing is being sent to my database so I would assume at least the 'if(err)' condition would run but it doesn't. I am new to glcoud so I am not sure if I am doing something wrong here? I am following the doc at https://googlecloudplatform.github.io/gcloud-node/#/docs/v0.26.0/datastore/transaction?method=save.
回答1:
In the context of a transaction, the save method doesn't actually need a callback. The things you wish to save are queued up until you call done(). Calling done will commit the transaction.
You can then handle errors from the commit operation in a second function passed to runInTransaction. See https://googlecloudplatform.github.io/gcloud-node/#/docs/v0.26.0/datastore/dataset?method=runInTransaction for examples of that.
--
Just mentioning this since it relates to the rollback part: https://github.com/GoogleCloudPlatform/gcloud-node/issues/633 -- we're waiting on an upgrade to Datastore's API before tackling that issue.
来源：https://stackoverflow.com/questions/34320065/gcloud-datastore-transaction-issue-using-nodejs