Fix #738: add an SNMP source Kamelet

[oscerd]

Fixes #738.

The issue asks for "a camel-snmp kamelet" without saying which shape. The component's own description — "Receive traps and poll SNMP capable devices" — is consumer shaped, and polling/trap-listening is what SNMP is overwhelmingly used for in an integration, so this adds a source. A producer Kamelet for GET/SET could follow if there is demand; happy to take that as a follow-up rather than guess at it now.

from:
  uri: "snmp:{{host}}:{{port}}"
  parameters:
    type: "{{type}}"
    oids: "{{?oids}}"
    protocol: "{{protocol}}"
    delay: "{{delay}}"
    snmpVersion: "{{snmpVersion}}"
    snmpCommunity: "{{snmpCommunity}}"
    treeList: "{{treeList}}"
    securityName: "{{?securityName}}"
    securityLevel: "{{securityLevel}}"
    authenticationProtocol: "{{?authenticationProtocol}}"
    authenticationPassphrase: "{{?authenticationPassphrase}}"
    privacyProtocol: "{{?privacyProtocol}}"
    privacyPassphrase: "{{?privacyPassphrase}}"
  steps:
  - to: "kamelet:sink"

Properties

Only host is required. type selects the mode; oids lists what to query.

property	default	notes
host	—	required
port	161	161 for polling, 162 for trap listening
type	POLL	enum: POLL / GET_NEXT / TRAP
oids	—	comma separated; needed for POLL and GET_NEXT, unused for TRAP
protocol	udp	enum: udp / tcp
delay	60000	poll interval; unused for TRAP
snmpVersion	0	0=v1, 1=v2c, 3=v3
snmpCommunity	public	credentials descriptor — see below
treeList	false	GET_NEXT only
securityName	—	v3, credentials descriptor
securityLevel	3	v3: 1=noAuthNoPriv, 2=authNoPriv, 3=authPriv
authenticationProtocol	—	enum: MD5 / SHA1
authenticationPassphrase	—	format: password + credentials
privacyProtocol	—	e.g. DES, AES128
privacyPassphrase	—	format: password + credentials

On the community string

snmpCommunity keeps the component default of public. I want to be explicit about that choice rather than let it pass unnoticed, given the catalog's secure-by-default direction.

SNMP v1 and v2c send the community string in clear text on the wire. Changing the Kamelet default from public to something else would not make it secret — it would just make the Kamelet fail against devices left on the default, while still transmitting the value unencrypted. The real mitigation is v3 with authPriv, so the Kamelet:

• marks snmpCommunity with the credentials descriptor so tooling groups it with secrets,
• says in the property description that it is a clear-text shared secret,
• and points at snmpVersion: 3 in the Kamelet description itself.

securityLevel defaults to 3 (authPriv), the strongest of the three, so an operator who moves to v3 gets authentication and privacy unless they deliberately weaken it.

Happy to be overruled if reviewers would rather have no default community at all.

Verification

script/validator reports no errors, script/generator adds the nav.adoc entry, mvn clean install passes from the repository root.

Parameter binding checked against the real component with camel run rather than by eye — unlike a network-dependent sink this one starts cleanly with no device present:

Routes startup (total:1 started:1 kamelets:1)
    Started snmp-probe (kamelet:snmp-source)
Apache Camel 4.21.0-SNAPSHOT (snmp-probe) started in 175ms

All thirteen parameters bound with no unknown option error; the consumer then polls a device that is not there, which is the expected quiet outcome.

No Citrus test — exercising this needs a real SNMP agent and the project's Citrus/Testcontainers toolchain has none, so it is marked Preview and does not carry kamelet.verified=true.

The icon is a plain SVG glyph authored for this Kamelet, consistent with how other protocol-based Kamelets (ssh-sink, ftp-sink) use generic glyphs rather than a vendor logo.

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Claude Code on behalf of Andrea Cosentino