[ci] Retry installing gradle/wrapper up to 5 times

[brianseeders]

Gradle wrapper does not have a built-in mechanism to retry downloads/installs, and downloads timeout fairly frequently.

Calling ./gradlew --version will cause gradlew to install everything without doing any other real work. Let's use that in a retry loop.

Adding this retry mechanism to these two scripts should cover almost all of CI.

[elasticsearchmachine]

Pinging @elastic/es-delivery (Team:Delivery)

[mark-vieira]

LGTM, although, one question is how often are our CI builds actually downloading the wrapper? It should already be cached on CI agents. Does this only happen occasionally, like when we bump the wrapper version or do we consistently see that builds are having to download the wrapper?

[brianseeders]

@elasticmachine merge upstream

[brianseeders]

LGTM, although, one question is how often are our CI builds actually downloading the wrapper? It should already be cached on CI agents. Does this only happen occasionally, like when we bump the wrapper version or do we consistently see that builds are having to download the wrapper?

@mark-vieira I somehow didn't realize, but the original complaint was actually for the lucene builds (I've added this there). I believe we should only download it between bumps and next image build. Still seems worth adding here since it's already done?

[mark-vieira]

@mark-vieira I somehow didn't realize, but the original complaint was actually for the lucene builds (I've added this there). I believe we should only download it between bumps and next image build. Still seems worth adding here since it's already done?

Sure.

[breskeby]

are there by now any more gradle invocations?

[brianseeders]

are there by now any more gradle invocations?

just checked, still looks good