Regexp in searching for aliases

m.hashemian · January 26, 2018, 9:22pm

Hi,

I have multiple indices and each index has multiple aliases. Is there a way to search for aliases using regexp?

For example, I can use this query:

curl -XGET 'localhost:9200/_alias/2016*?pretty'

to get all aliases starting with 2016, but if I want to get all aliases starting with 2016 and 2017 (but not 2015 or 2018), how could I achieve this? I tried different variations of this:

curl -XGET 'localhost:9200/_alias/2016*|2017*?pretty'

but it did not work.

Thanks a lot

nik9000 · January 26, 2018, 9:40pm

Regular expressions aren't supported. You can only use the glob style thing. This is what implements it:

github.com

elastic/elasticsearch/blob/master/server/src/main/java/org/elasticsearch/common/regex/Regex.java#L79


        throw new IllegalArgumentException("There must be at least one pattern, zero given");
    }
    List<Automaton> automata = new ArrayList<>();
    for (String pattern : patterns) {
        automata.add(simpleMatchToAutomaton(pattern));
    }
    return Operations.union(automata);
}


/**
 * Match a String against the given pattern, supporting the following simple
 * pattern styles: "xxx*", "*xxx", "*xxx*" and "xxx*yyy" matches (with an
 * arbitrary number of pattern parts), as well as direct equality.
 *
 * @param pattern the pattern to match against
 * @param str     the String to match
 * @return whether the String matches the given pattern
 */
public static boolean simpleMatch(String pattern, String str) {
    if (pattern == null || str == null) {
        return false;

m.hashemian · January 26, 2018, 9:44pm

I suspected that's the case. Do you know any other way to query aliases with one request (like search)? I can send multiple requests (e.g. one for 2016*, one for 2017*, etc) but I hoped to find a better way.

Thanks

m.hashemian · January 26, 2018, 11:07pm

I actually ended up using the Client API for JavaScript for this. That allows using a comma-separated list of alias names. It still does not support regexp, as you said @nik9000, but it allows using "2016*,2017*" which serves my purpose.

Thanks

mayya · January 29, 2018, 6:59pm

If you want to search multiple aliases' patterns using Elastic http api, you can also try to separate them using comma. For example:

curl -XGET 'localhost:9200/_alias/2016*,2017*'

m.hashemian · January 30, 2018, 2:08pm

Ah, yes, you are right @mayya. That worked. Thanks.

system · February 27, 2018, 2:12pm

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