Cannot parse Arista EOS routes if MED is unset

[adamgent]

Bug Description

When looking up routes on Arista EOS platforms, if any of the returned routes have the MED unset an error is thrown and the loookup fails. Lookups where all routes returned have an MED value (e.g. 0 or 2001 etc) it works as expected.

Expected behavior

Look up a BGP route normally and get a table of results.

Steps to Reproduce

Lookup a route on arista_eos platform that you know has no MED set. example below;

#sho ip bgp 1.1.1.1 BGP routing table entry for 1.1.1.0/24 Paths: 2 available 13335 (aggregated by 13335 141.101.71.254) 195.66.225.179 from 195.66.225.179 (141.101.71.1) Origin IGP, metric -, localpref 200, weight 0, received 09:29:35 ago, valid, external, best

Local Configurations

No specific configuration needed.

Logs

[INFO] 20211202 16:31:33 | hyperglass.api.routes:90 | query → Starting query execution for query Query(query_location=london_gb, query_type=bgp_route, query_vrf=Global, query_target=1.1.1.0/24)
[CRITICAL] 20211202 16:31:35 | hyperglass.parsing.arista:53 | parse_arista → 1 validation error for AristaRoute
bgpRouteEntries -> 1.1.1.0/24 -> bgpRoutePaths -> 0 -> med
  field required (type=value_error.missing)
[CRITICAL] 20211202 16:31:35 | hyperglass.exceptions:40 | __init__ → [DANGER] 

Field: bgpRouteEntries → 1.1.1.0/24 → bgpRoutePaths → 0 → med
  Error: field required

Possible Solution

If MED is not set in the response, then set it as zero when parsing. It looks like something similar was done for iBGP routes!

Environment

Server

Metric	Value
hyperglass Version	1.0.4
hyperglass Path	/home/hyperglass/hyperglass
Python Version	3.6.8
Node Version	14.18.2
Platform Info	Linux-3.10.0-327.36.3.el7.centos.plus.x86_64-x86_64-with-centos-7.9.2009-Core
CPU Info	Intel Core Processor (Haswell, no TSX, IBRS)
Logical Cores	2
Physical Cores	2
Processor Speed	2.599996GHz
Total Memory	4.14 GB
Memory Utilization	10.1%
Total Disk Space	31.57 GB
Disk Utilization	15.0%

Client

• OS: Elementary OS 5
• Browser: Firefox