EZP-28088: Re-try connections when trying to reach Solr

[andrerom]

issue: https://jira.ez.no/browse/EZP-28088

Note: This does not handle HTTP error codes returned, as code uses ignore_errors, however afaik what is relevant here is cases where we don't reach Solr (network errors/dns/..). But if anyone see any other cases that would be relevant here please share :)

Also open question is if Solr would sometimes needs more time than 10s for handling calls, so might be timeout is too low here.

Todo:

• Logger

[adamwojs]

Extract hardcoded values to const would make the code more self-explanatory and easier to configure IMHO.

// Connection timeout in ms
const CONNECTION_TIMEOUT = 10000; 
// Number of connection attempts
const CONNECTION_RETRY_TIMES = 5;
// Connection retry in ms. Timeout is 10s, so time spent in worst case is 50.5s, 
// which is less then default_socket_timeout (60s)
const CONNECTION_RETRY_DELAY = 100;

// ...

for ($i = 0; $i < self::CONNECTION_RETRY_TIMES; $i++) {
	$responseMessage = $this->requestStream($method, $endpoint, $path, $message)
	if (responseMessage !== null) {
    	    return $responseMessage;
	}

 	// Wait before we retry
 	usleep(1000 * self::CONNECTION_RETRY_DELAY);
}

[andrerom]

true, but impossible yet to set them as private const, so might be better with properties?

[adamwojs]

+1, properties will be better.

[andrerom]

@adamwojs Better?