I am having troubles with sending faxes. I hope someone can help me work out a better method.

Basically we have a special address that our users can send to. It winds up on our Asterisk server which runs a Python script that parses the message for attachments and the phone number from the recipient address. The attachments are converted to TIFF and stored in a folder with various information encoded into the file name such as phone number and retry information. That all works fine.

A separate process picks up the files and sends them using an AMI script like this:

Action: Originate Channel: SIP/provider/%(destination)s Context: LocalSets CallerID: Vybe Consulting Inc Fax Service <6475551212>
Exten: sendfax Priority: 1
Timeout: 30000
Variable: faxfile=%(faxfile)s Variable: uid=%(uid)s Variable: destination=%(destination)s Variable: sender_name=Vybe Consulting Inc Fax Service Variable: sender_numd75551212

It then renames the file encoding the next retry time and incrementing the number of retries.

The same script checks for files in a success folder and sends the users a confirmation message that the fax was sent. The files are moved into the success folder by Asterisk using this dialplan:

sendfax,1,Verbose(0,FAX ${faxfile} to ${destination})
same => n,Set(FAXOPT(headerinfo)=${sender_name})
same => n,Set(FAXOPT(localstationid)=${sender_num})
same => n,SendFax(${faxfile},d)
same => n,Set(STATUS=Status: ${FAXOPT(status)})
same => n,Set(STATUS=${STATUS}\nRemote ID: ${FAXOPT(remotestationid)})
same => n,Set(STATUS=${STATUS}\nMaxrate: ${FAXOPT(maxrate)})
same => n,Set(STATUS=${STATUS}\nMinrate: ${FAXOPT(minrate)})
same => n,Set(STATUS=${STATUS}\nECM: ${FAXOPT(ecm)})
same => n,Set(STATUS=${STATUS}\nnumber of pages: ${FAXOPT(pages)})
same => n,Set(STATUS=${STATUS}\nRate: ${FAXOPT(rate)})
same => n,Set(STATUS=${STATUS}\nResolution: ${FAXOPT(resolution)})
same => n,GotoIf($[“${FAXOPT(status)}” = “SUCCESS”]?faxok)
same => n,Set(STATUS=${STATUS}\nError: ${FAXOPT(error)})
same => n(faxok),Verbose(0,FAX ${destination} Status (S): ${STATUS})
same => n,Set(FAXNAME=${CUT(faxfile,/,6)})
same => n,Set(FILE(/fax_status/${FAXNAME})=${STATUS})
same => n,GotoIf($[“${FAXOPT(status)}” != “SUCCESS”]?faxfail)
same => n,System(/bin/mv ‘${faxfile}’ ‘/fax_success/${FAXNAME}’)

same => n,Set(CDR(userfield)=${destination})
same => n,Verbose(0,FAX to ${destination} charged to ${uid})
same => n(faxfail),Verbose(0,FAX ${destination} Status (F): ${STATUS})
same => n,Hangup()

My problem is that if the faxes get too big it starts sending it again before the previous one has finished. I can’t raise the retry limit too far because sometimes the receiver is busy and we have to retry in a reasonable time.

Is there a way to get a token from the AMI script that I can use to determine later if Asterisk is still busy with the fax before I try sending it again?

Or, am I approaching this all wrong? Is there a better method of doing this?

I am running Asterisk 13.19.0 on NetBSD/amd64 7.1.0.