Group Property Reader
Group Property Readers are used to read out components of a device with multiple, related values. They are mostly used for reading out components that exist multiple times within a device (e.g. interfaces).
Like a property reader, a group property reader always has a detection type. This type
defines how the values are read out. Currently, Thola only supports one detection type:
snmpwalk. This detection type reads out values through snmpwalks and maps these values to
groups based on the indices of the snmp responses.
The base structure of a group property reader looks like this:
|detection||Describes how to retrieve the value|
|values||Key + Value list of values which will be read out|
The structure of an element of the
values list depends on the detection type of the group property reader.
snmpwalk, these elements have the following structure:
|oid||OID which will be walked to retrieve values|
|operators||array of operators to normalize a value, optionally|
|indices_mapping||map indices of snmpwalk result to another snmpwalk, optionally|
oid parameter is a string that contains the OID which will be walked.
operators can be added
optionally to normalize or filter values returned by the snmpwalk.
The following example shows the group property reader for reading out network interfaces:
detection: snmpwalk values: ifIndex: oid: 220.127.116.11.18.104.22.168.1.1 ifDescr: oid: 22.214.171.124.126.96.36.199.1.2 ifType: oid: 188.8.131.52.184.108.40.206.1.3 operators: - type: modify modify_method: map mappings: ifType.yaml ifSpeed: oid: 220.127.116.11.18.104.22.168.1.5 ifAdminStatus: oid: 22.214.171.124.126.96.36.199.1.7 operators: - type: modify modify_method: map ignore_on_mismatch: true mappings: "1": "up" "2": "down" "3": "testing" ...
Usually the results of all single snmpwalks are put together in groups based on the
last index of the oid which was returned during the snmpwalk.
indices_mapping allows changing
this index by assigning it to another snmpwalk result. This is necessary when you want to group a
result of an snmpwalk together with other values that are not part of the same snmp table, but a conversion
oid for these snmp tables exists.
indices_mapping is used in the following example for reading out CRC align errors of
network interfaces. These errors are in a different snmp table and not indexed by the ifIndex of
an interface, but there is a conversion table which maps these special indices to an ifIndex:
etherStatsCRCAlignErrors: oid: 188.8.131.52.184.108.40.206.1.1.8 indices_mapping: oid: 220.127.116.11.18.104.22.168.1.1.2 operators: - type: modify modify_method: regexSubmatch regex: '\.?([0-9]+)$' format: "$1"
Within a group property reader, values can again be grouped under a key inside of the
values map. This is a special case in which a value does not consist of an oid and optionally
operators and an indices mapping. Instead, a value simple contains one parameter
values, which again is a list of multiple values. All values which are grouped
under the same key will be grouped in the result Thola returns aswell. This is mostly used
when reading out information of a group that belongs together, for instance information
about a special interface type.
This example shows a part of a group property reader for reading out interfaces. Some values which only exist for radio interfaces are grouped together under the value “radio”:
ifIndex: oid: 22.214.171.124.126.96.36.199.1.1 ifDescr: oid: 188.8.131.52.184.108.40.206.1.2 radio: values: level_in: oid: 220.127.116.11.4.1.2218.104.22.168.1.2 level_out: oid: 22.214.171.124.4.1.22126.96.36.199.1.3