gosmi translator fails to initialize snmp_trap plugin with large MIB collections containing syntax errors

[ronaldde]

Relevant telegraf.conf

[global_tags]
type = "snmpTrap"

[agent]
interval = "15s"
round_interval = true
metric_batch_size = 1000
metric_buffer_limit = 10000
collection_jitter = "0s"
flush_interval = "10s"
flush_jitter = "0s"
precision = ""
snmp_translator = "gosmi"  # Fails with gosmi, works with netsnmp
logfile = ""
debug = true
quiet = false
hostname = "$HOSTNAME"
omit_hostname = false

[inputs]
[inputs.internal]
collect_memstats = true

[inputs.snmp_trap]
auth_password = "${AUTH_PASSWORD}"
auth_protocol = "SHA"
path = ["/usr/share/snmp/mibs", "/mibs"]
priv_password = "${PRIV_PASSWORD}"
priv_protocol = "AES"
sec_level = "authPriv"
sec_name = "stingertraps"
service_address = "udp://:162"
version = "3"
[inputs.snmp_trap.tags]
severity = "critical"

Logs from Telegraf

2026-01-16T00:07:13Z I! Starting Telegraf 1.37.0 brought to you by InfluxData the makers of InfluxDB
2026-01-16T00:07:13Z I! Available plugins: 243 inputs, 9 aggregators, 35 processors, 26 parsers, 67 outputs, 8 secret-stores
2026-01-16T00:07:13Z I! Loaded inputs: internal snmp_trap
2026-01-16T00:07:13Z I! Loaded aggregators:
2026-01-16T00:07:13Z I! Loaded processors: lookup
2026-01-16T00:07:13Z I! Loaded secretstores:
2026-01-16T00:07:13Z I! Loaded outputs: file health prometheus_client
2026-01-16T00:07:13Z I! Tags enabled: host=8721d5f47c50 type=snmpTrap
2026-01-16T00:07:13Z I! [agent] Config: Interval:15s, Quiet:false, Hostname:"8721d5f47c50", Flush Interval:10s
2026-01-16T00:07:13Z W! [agent] The default value of 'skip_processors_after_aggregators' will change to 'true' with Telegraf v1.40.0! If you need the current default behavior, please explicitly set the option to 'false'!
2026-01-16T00:07:13Z D! [agent] Initializing plugins

System info

Telegraf 1.37.0 (git: HEAD@f80cc596)

Docker

telegraf-snmptrap:
image: hub.docker.internal.cba/telegraf:1.37.0
profiles: ["core"]
environment:
- MIMIR_BASE_URL=http://mimir:9009
ports:
- "162:162/udp"
networks:
- management
env_file:
- "./docker/telegraf_snmptrap/.env"
volumes:
- "./docker/telegraf_snmptrap/:/etc/telegraf/:ro"
- "./mibs:/mibs:ro"
command: ["--debug", "--config-directory", "/etc/telegraf/"]

Steps to reproduce

1. Set up a large MIB collection (1689+ .my files) containing Cisco MIBs with various syntax issues
2. Configure snmp_trap input with snmp_translator = "gosmi"
3. Start Telegraf

Expected behavior

Telegraf should start successfully and listen for SNMP traps, gracefully handling MIB files with syntax errors (similar to netsnmp behavior).

Can confirm if changing the snmp_translator to netsnmp telegraf starts successfully.

Actual behavior

Telegraf hangs indefinitely at "Initializing plugins" and never completes startup. The process must be killed and restarted.

Additional info

Total MIB files: 1,689 .my files
Source: Cisco MIB collection with various versions and modules
Known problematic MIBs: Multiple files with syntax errors, including:
Files with multiple DEFINITIONS ::= BEGIN statements
Files with parsing errors (unexpected tokens, missing dependencies)
Files with ASN.1 syntax issues

[srebhan]

@ronaldde this is an issue in gosmi! While I do agree that users are left alone with MIB files not adhering to the specification, I don't think Telegraf can do anything here.

[ronaldde]

Thank you @srebhan
I have logged an upstream issue sleepinggenius2/gosmi#52

[Hipska]

gosmi is more strict in regards of malformed MIBs. It is up to the user/vendor to fix the issues.

However the fact telegraf seems to hang should be looked into as gosmi normally returns errors in these situations.

Try to reduce the set of files to the one(s) that are problematic so it can be reproduced.