Kevin A. McGrail > Mail-SpamAssassin > Mail::SpamAssassin::AsyncLoop

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NAME ^

Mail::SpamAssassin::AsyncLoop - scanner asynchronous event loop

DESCRIPTION ^

An asynchronous event loop used for long-running operations, performed "in the background" during the Mail::SpamAssassin::check() scan operation, such as DNS blocklist lookups.

METHODS ^

$ent = $async->start_lookup($ent, $master_deadline)

Register the start of a long-running asynchronous lookup operation. $ent is a hash reference containing the following items:

key (required)

A key string, unique to this lookup. This is what is reported in debug messages, used as the key for get_lookup(), etc.

id (required)

An ID string, also unique to this lookup. Typically, this is the DNS packet ID as returned by DnsResolver's bgsend method. Sadly, the Net::DNS architecture forces us to keep a separate ID string for this task instead of reusing key -- if you are not using DNS lookups through DnsResolver, it should be OK to just reuse key.

type (required)

A string, typically one word, used to describe the type of lookup in log messages, such as DNSBL, MX, TXT.

zone (optional)

A zone specification (typically a DNS zone name - e.g. host, domain, or RBL) which may be used as a key to look up per-zone settings. No semantics on this parameter is imposed by this module. Currently used to fetch by-zone timeouts.

timeout_initial (optional)

An initial value of elapsed time for which we are willing to wait for a response (time in seconds, floating point value is allowed). When elapsed time since a query started exceeds the timeout value and there are no other queries to wait for, the query is aborted. The actual timeout value ranges from timeout_initial and gradually approaches timeout_min (see next parameter) as the number of already completed queries approaches the number of all queries started.

If a caller does not explicitly provide this parameter or its value is undefined, a default initial timeout value is settable by a configuration variable rbl_timeout.

If a value of the timeout_initial parameter is below timeout_min, the initial timeout is set to timeout_min.

timeout_min (optional)

A lower bound (in seconds) to which the actual timeout approaches as the number of queries completed approaches the number of all queries started. Defaults to 0.2 * timeout_initial.

$ent is returned by this method, with its contents augmented by additional information.

$ent = $async->bgsend_and_start_lookup($domain, $type, $class, $ent, $cb, %options)

A common idiom: calls bgsend, followed by a call to start_lookup, returning the argument $ent object as modified by start_lookup and filled-in with a query ID.

$ent = $async->get_lookup($key)

Retrieve the pending-lookup object for the given key $key.

If the lookup is complete, this will return undef.

Note that a lookup is still considered "pending" until complete_lookups() is called, even if it has been reported as complete via set_response_packet().

$async->log_lookups_timing()

Log sorted timing for all completed lookups.

$alldone = $async->complete_lookups()

Perform a poll of the pending lookups, to see if any are completed. Callbacks on completed queries will be called from poll_responses().

If there are no lookups remaining, or if too much time has elapsed since any results were returned, 1 is returned, otherwise 0.

$async->abort_remaining_lookups()

Abort any remaining lookups.

$async->set_response_packet($id, $pkt, $key, $timestamp)

Register a "response packet" for a given query. $id is the ID for the query, and must match the id supplied in start_lookup(). $pkt is the packet object for the response. A parameter $key identifies an entry in a hash %{$self->{pending_lookups}} where the object which spawned this query can be found, and through which futher information about the query is accessible.

$pkt may be undef, indicating that no response packet is available, but a query has completed (e.g. was aborted or dismissed) and is no longer "pending".

The DNS resolver's response packet $pkt will be made available to a callback subroutine through its argument as well as in $ent-<gt{response_packet}>.

$async->report_id_complete($id,$key,$key,$timestamp)

Legacy. Equivalent to $self->set_response_packet($id,undef,$key,$timestamp), i.e. providing undef as a response packet. Register that a query has completed and is no longer "pending". $id is the ID for the query, and must match the id supplied in start_lookup().

One or the other of set_response_packet() or report_id_complete() should be called, but not both.

$time = $async->last_poll_responses_time()

Get the time of the last call to poll_responses() (which is called from complete_lookups(). If poll_responses() was never called or abort_remaining_lookups() has been called last_poll_responses_time() will return undef.

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