How to cancel update in elasticsearch painless script

While working on trying to switch out PHP code with pure elasticsearch-painless, I noticed that the document doesn’t return “noop” even if the document is identical before and after update.

I’m not sure if there is any consequences of having a version update for every time the code is executed? How does it scale?

I’m simply trying to update the views of a post during visit if the identity was not found in views_log, and was wondering either if there is a way to fix the “noop” return, or somehow have it cancel the update?

The code I have right now looks like this:

$script = 'if (!ctx._source.views_log.contains(params.identity)) {
             ctx._source.views_log.add(params.identity);
             ctx._source.views += 1;
           }';

$params = [
    'index' => 'post',
    'id'    => 4861,
    'body'  => [
        'script' => [
            'source' => $script,
            'lang' => "painless",
            'params' => [
                'identity' => $identifier
            ]
        ]
    ]
];

$response = $client->update($params);

Following elasticsearch’s documentation:

ctx[‘op’]: Use the default of index to update a document. Set to none to specify no operation or delete to delete the current document from the index.

I tried setting ctx.op to none if the condition is not met, but that didn’t seem to work.

Answer

During writing of this question I figured it out, and might as well share with others.

---

none is an accepted keyword for ctx.op, it accepts a string. Change none to "none".

So the full script should look like this:

$script = 'if (!ctx._source.views_log.contains(params.identity)) {
             ctx._source.views_log.add(params.identity);
             ctx._source.views += 1;
           } else {
             ctx.op = "none";
           }';

$params = [
    'index' => 'post',
    'id'    => 4861,
    'body'  => [
        'script' => [
            'source' => $script,
            'lang' => "painless",
            'params' => [
                'identity' => $identifier
            ]
        ]
    ]
];

$response = $client->update($params);

This will give the desired "result": "noop"