Compatibility needs hacking to work (Client 7.3 ==> Server 6.8)

[truj]

I'm trying to use Search::Elasticsearch 7.3 together with Elasticsearch 6.8.
Referring to this comment, I've tried

my $es = Search::Elasticsearch->new(
    client => '6_0::Direct',
    %other_settings,
);

But I get this error:
Can't locate Search/Elasticsearch/Client/6_0/Direct.pm

Checking the install, I found out that there is indeed no file 6_0.pm inside of blib/lib/Search/Elasticsearch/Client/.
So I copied Search/Elasticsearch/Client/6_0.pm and (recursively) Search/Elasticsearch/Client/6_0/ from an old installation (Client version 6.8) to the new installation (Client version 7.3).
Now it seems to work.

My suggestion:
Include the newest 6.x client code into the 7.x client as well, so that the compatibility mode is working without hacks.
This is especially useful for upgrade scenarios like ours.
We try to minimize our down time during the upgrade. So we upgrade in several steps:

• status quo: client 6.8 + server 6.8
• client 7.3 in compatibility mode + server 6.8
• client 7.3 in normal mode + server 6.8

[ezimuel]

@truj thanks for reporting this. I'm investigating the issue, I'll update asap.

[ezimuel]

@truj because we are building Client versions with different packages, you need to install Search::Elasticsearch::Client::6_0 manually after the installation of Search::Elasticsearch. Basically, the Search::Elasticsearch package will install the latest version (7), if you want the previous one (6) you need to require it explicitly.

Using cpanm you can type the following command:

cpanm Search::Elasticsearch::Client::6_0

This will add the Client::6_0 support into the previous Search::Elasticsearch installation.

[truj]

Great, thank you for the explanation.