Filter enrich policy index deletes to just the policy's associated indices

[joegallo]

If you have two enrich policies, and the name of the one plus a dash is a prefix for the name of the other (e.g. "policy-test" and "policy-test-more"), then if you delete the prefix policy the indices associated with the other policy will get deleted, too.

[elasticmachine]

Pinging @elastic/es-data-management (Team:Data Management)

[joegallo]

I did a little bit of spelunking back to when enrich was first added to master via #48039.

    private void prepareAndCreateEnrichIndex() {
         long nowTimestamp = nowSupplier.getAsLong();
         String enrichIndexName = EnrichPolicy.getBaseName(policyName) + "-" + nowTimestamp;
         Settings enrichIndexSettings = Settings.builder()

     public static String getBaseName(String policyName) {
         return ENRICH_INDEX_NAME_BASE + policyName;
     }

    public static final String ENRICH_INDEX_NAME_BASE = ".enrich-";

The important thing is that it's always been the case that the pattern is prefix-policy_name-timestamp -- if that had ever changed, then there'd maybe be some concern here that I was making it possible that some backing indices would never get deleted (like, say, if the pattern had at one point been prefix-policy_name-BACKING-timestamp -- the current code would have still deleted that, but my new code would not).

[martijnvg]

LGTM, good catch!

[martijnvg]

maybe make these variables explicitly immutable?

[joegallo]

✅, d1658cf

[joegallo]

@hendry-lim hasn't it? I'm seeing bae4e11 for 8.0 and 6bab477 for 7.17.