This subsystem is charged with the task of retrieving new alerts from the alert queue that event engine generates and sending them to users if they match their alert profile. NAV 3.5 should be getting a new version of this system which is a Python rewrite of the original Perl system.
The alert profile system was originally designed with maximum flexibility in mind and is thus a fairly complex system. Each account in NAV can have one or more alert profiles which designate when daily and weekly queues should be emptied, only one of these can be active for any user. Each profile has a set of time periods which in turn have alert subscriptions. An alert subscription basically says if an alert matches a filtergroup send it to this address.
Understanding how we check a filtergroup against an alert is where most of the complexity of the system comes into light. Each filtergroup has filtergroupcontents which designate how the set of filters the contents specify should be combined. The filtergroupcontents is where 'inclusion', 'exclusion', 'and' and 'add inverse' (simply a negated add) opperations are set up.
To actually see if an alert matches we simply compile all the expressions in a filter into a Django-ORM lookup and do a 'SELECT COUNT(*) FROM …' which will tell us if our filter matches. The mapping we generate is combined with standard ORM lookups except for a few special cases like IP's. The following mapping shows how the current (as of 2008-06-19) mapping is setup from database table+column to the ORM (MatchField.CHOICES contains the sameinformation):
alertq.alertqid: id
alertq.alerttypeid: alert_type_id
alertq.deviceid: device_id
alertq.eventtypeid: event_type_id
alertq.netboxid: netbox_id
alertq.severity: severity
alertq.source: source_id
alertq.state: state
alertq.subid: subid
alertq.time: time
alertq.value: value
alerttype.alerttype: alert_type__name
alerttype.alerttypedesc: alert_type__description
alerttype.alerttypeid: alert_type__id
alerttype.eventtypeid: alert_type__event_type_id
arp.arpid: netbox__arp__id
arp.end_time: netbox__arp__end_time
arp.ip: netbox__arp__ip
arp.mac: netbox__arp__mac
arp.netboxid: netbox__arp__netbox_id
arp.prefixid: netbox__arp__prefix_id
arp.start_time: netbox__arp__start_time
arp.sysname: netbox__arp__sysname
cam.camid: netbox__cam__id
cam.end_time: netbox__cam__end_time
cam.ifindex: netbox__cam__ifindex
cam.mac: netbox__cam__mac
cam.misscnt: netbox__cam__miss_count
cam.module: netbox__cam__module
cam.netboxid: netbox__cam__netbox_id
cam.port: netbox__cam__port
cam.start_time: netbox__cam__start_time
cam.sysname: netbox__cam__sysname
cat.catid: netbox__category__id
cat.descr: netbox__category__description
cat.req_snmp: netbox__category__req_snmp
device.active: netbox__device__active
device.auto: netbox__device__auto
device.deviceid: netbox__device__id
device.deviceorderid: netbox__device__device_order_id
device.discovered: netbox__device__discovered
device.fw_ver: netbox__device__firmware_version
device.hw_ver: netbox__device__hardware_version
device.productid: netbox__device__product_id
device.serial: netbox__device__serial
device.sw_ver: netbox__device__software_version
eventtype.eventtypedesc: event_type__description
eventtype.eventtypeid: event_type__id
eventtype.stateful: event_type__stateful
gwport.gwportid: netbox__connected_to_gwport__id
gwport.ifindex: netbox__connected_to_gwport__ifindex
gwport.interface: netbox__connected_to_gwport__interface
gwport.link: netbox__connected_to_gwport__link
gwport.masterindex: netbox__connected_to_gwport__master_index
gwport.metric: netbox__connected_to_gwport__metric
gwport.moduleid: netbox__connected_to_gwport__module_id
gwport.portname: netbox__connected_to_gwport__port_name
gwport.speed: netbox__connected_to_gwport__speed
gwport.to_netboxid: netbox__connected_to_gwport__to_netbox_id
gwport.to_swportid: netbox__connected_to_gwport__to_swport_id
location.descr: netbox__room__location__description
location.locationid: netbox__room__location__id
mem.device: netbox__memory__device
mem.memid: netbox__memory__id
mem.memtype: netbox__memory__type
mem.netboxid: netbox__memory__netbox_id
mem.size: netbox__memory__size
mem.used: netbox__memory__used
netbox.catid: netbox__category_id
netbox.deviceid: netbox__device_id
netbox.discovered: netbox__discovered
netboxinfo.key: netbox__info__key
netboxinfo.netboxid: netbox__info__netbox_id
netboxinfo.netboxinfoid: netbox__info__id
netboxinfo.val: netbox__info__value
netboxinfo.var: netbox__info__variable
netbox.ip: netbox__ip
netbox.netboxid: netbox__id
netbox.orgid: netbox__organization_id
netbox.prefixid: netbox__prefix_id
netbox.ro: netbox__read_only
netbox.roomid: netbox__room_id
netbox.rw: netbox__read_write
netbox.snmp_agent: netbox__snmp_agent
netbox.snmp_version: netbox__snmp_version
netbox.sysname: netbox__sysname
netbox.typeid: netbox__type_id
netbox.up: netbox__up
netbox.upsince: netbox__up_since
netbox.uptodate: netbox__up_to_date
org.descr: netbox__organization__description
org.opt1: netbox__organization__optional_1
org.opt2: netbox__organization__optional_2
org.opt3: netbox__organization__optional_3
org.orgid: netbox__organization__id
org.parent: netbox__organization__parent_id
prefix.netaddr: netbox__prefix__net_address
prefix.prefixid: netbox__prefix__id
prefix.vlanid: netbox__prefix__vlan_id
product.descr: netbox__device__product__description
product.productid: netbox__device__product__id
product.productno: netbox__device__product__product_number
product.vendorid: netbox__device__product__vendor_id
room.descr: netbox__room__description
room.locationid: netbox__room__location_id
room.opt1: netbox__room__optional_1
room.opt2: netbox__room__optional_2
room.opt3: netbox__room__optional_3
room.opt4: netbox__room__optional_4
room.roomid: netbox__room__id
subcat.catid: netbox__category__subcategory__category_id
subcat.descr: netbox__category__subcategory__description
subcat.subcatid: netbox__category__subcategory__id
swport.duplex: netbox__connected_to_swport__duplex
swport.ifindex: netbox__connected_to_swport__ifindex
swport.interface: netbox__connected_to_swport__interface
swport.link: netbox__connected_to_swport__link
swport.media: netbox__connected_to_swport__media
swport.moduleid: netbox__connected_to_swport__module_id
swport.portname: netbox__connected_to_swport__port_name
swport.port: netbox__connected_to_swport__port
swport.speed: netbox__connected_to_swport__speed
swport.swportid: netbox__connected_to_swport__id
swport.to_netboxid: netbox__connected_to_swport__to_netbox_id
swport.to_swportid: netbox__connected_to_swport__to_swport_id
swport.trunk: netbox__connected_to_swport__trunk
swport.vlan: netbox__connected_to_swport__vlan
type.cdp: netbox__type__cdp
type.chassis: netbox__type__chassis
type.cs_at_vlan: netbox__type__cs_at_vlan
type.descr: netbox__type__description
type.frequency: netbox__type__frequency
type.sysobjectid: netbox__type__sysobject
type.tftp: netbox__type__tftp
type.typeid: netbox__type__id
type.typename: netbox__type__name
type.vendorid: netbox__type__vendor_id
usage.descr: netbox__organization__vlan__usage__description
usage.usageid: netbox__organization__vlan__usage__id
vendor.enterpriseid: netbox__device__product__vendor__enterprise_id
vendor.vendorid: netbox__device__product__vendor__id
vlan.description: netbox__organization__vlan__description
vlan.netident: netbox__organization__vlan__net_ident
vlan.nettype: netbox__organization__vlan__net_type_id
vlan.orgid: netbox__organization__vlan__organization_id
vlan.usageid: netbox__organization__vlan__usage_id
vlan.vlanid: netbox__organization__vlan__id
vlan.vlan: netbox__organization__vlan__vlan