net.SplitHostPort only works if you provide both address and port, and it only accepts IPv6 literals if they are in square brackets.
https://go.dev/play/p/ezUD89xLd6z Therefore I think the logic has to be more sophisticated: * Contains no colons: just a hostname * Contains exactly one colon: parse with SplitHostPort * Contains two or more colons: * does not start with "[": just a hostname * starts with "[" and ends with "]": just a hostname inside the brackets * otherwise: parse with SplitHostPort On Friday 15 December 2023 at 11:29:04 UTC Brian Candler wrote: > Done: > https://github.com/prometheus/snmp_exporter/issues/1076 > https://github.com/prometheus/blackbox_exporter/issues/1171 > > BTW, there's no problem with http prober and URLs with IPv6 literals. It > turns out the http prober module I was testing with initially had > preferred_ip_protocol: "ip4" > ip_protocol_fallback: false > > On Friday 15 December 2023 at 07:04:02 UTC Ben Kochie wrote: > >> Oh, I forgot to add, it would be helpful to file issues on the affected >> repos. >> >> On Fri, Dec 15, 2023 at 8:03 AM Ben Kochie <sup...@gmail.com> wrote: >> >>> Yea, that's some inconsistency we should fix. I agree, we should allow >>> square brackets everywhere, but only require them if a port is required. >>> >>> Consistently using https://pkg.go.dev/net#SplitHostPort should help. >>> >>> On Thu, Dec 14, 2023 at 7:01 PM 'Brian Candler' via Prometheus Users < >>> promethe...@googlegroups.com> wrote: >>> >>>> I'd like to raise this as a general issue for discussion. I am working >>>> with these: >>>> >>>> blackbox_exporter, version 0.24.0 (branch: HEAD, revision: >>>> 0b0467473916fd9e8526e2635c2a0b1c56011dff) >>>> build user: root@e5bbfcc8184e >>>> build date: 20230516-11:07:25 >>>> go version: go1.20.4 >>>> platform: linux/amd64 >>>> tags: netgo >>>> >>>> snmp_exporter, version 0.25.0 (branch: HEAD, revision: >>>> 9c42d6c874d479314e612bca69558c81f8e26287) >>>> build user: root@880115266f70 >>>> build date: 20231210-10:05:18 >>>> go version: go1.21.5 >>>> platform: linux/amd64 >>>> tags: netgo >>>> >>>> In blackbox_exporter, it's inconsistent whether IPv6 literals need to >>>> be enclosed in square brackets or not. >>>> >>>> - With the icmp prober, IPv6 literals *must not* be enclosed in >>>> brackets AFAICS >>>> - With the dns prober, IPv6 literals *must not* be enclosed in >>>> brackets, unless you also provide a port. e.g. [::1] is invalid, but >>>> [::1]:53 is OK, as far as I can tell >>>> - With the tcp prober, I don't think the port can be omitted anyway; >>>> hence IPv6 literals *must* be enclosed in brackets and followed by :port >>>> >>>> This makes it difficult to write generic code to map a device to a >>>> target plus module, because it depends on what underlying prober the >>>> module >>>> is using. >>>> >>>> Looking at the wider Prometheus ecosystem: >>>> >>>> - Prometheus service discovery requires square brackets, because >>>> __address__ is an address:port combination >>>> - snmp_exporter does *not* allow the square brackets in the target >>>> address if it doesn't have a port. Conversely, you can add the square >>>> brackets, but if you do you *must* add a port; it doesn't add :161 >>>> automatically. (This is like the dns prober in blackbox_exporter) >>>> >>>> # curl -vsS >>>> 'localhost:9116/snmp?target=[2001:db8::1]&module=mikrotik&auth=workshop_v3' >>>> error collecting metric Desc{fqName: "snmp_error", help: "Error >>>> scraping target", constLabels: {module="mikrotik"}, variableLabels: {}}: >>>> error connecting to target [2001:db8::1]: error establishing connection to >>>> host: dial udp: address [[2001:db8::1]]:161: missing port in address >>>> >>>> That looks like a straightforward bug to me: it seems to be attempting >>>> to add the :161 port, but is mangling it with an extra set of brackets. >>>> >>>> If that can be fixed (and maybe it's the same issue in dns prober), >>>> then it will be possible to use brackets around IPv6 addresses without >>>> ports. >>>> >>>> That leaves the icmp prober in blackbox exporter. I think it should >>>> allow square brackets, if not actually require them (there's no useful >>>> concept of "port" here, it will always send an echo-request). It might be >>>> more consistent to require square brackets >>>> >>>> P.S. I would expect the blackbox_exporter http prober to require square >>>> brackets around IPv6 literals in URLs, but I can't them to work: e.g. >>>> curl -g >>>> 'localhost:9115/probe?target=http:%2f%2f%5b2001:db8::1%5d&module=http_2xx_example' >>>> doesn't make an outbound connection to 2001:db8::1. But quite possibly >>>> I'm doing something wrong. >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Prometheus Users" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to prometheus-use...@googlegroups.com. >>>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/prometheus-users/433eea9b-2b74-4375-9112-ca671baf84c9n%40googlegroups.com >>>> >>>> <https://groups.google.com/d/msgid/prometheus-users/433eea9b-2b74-4375-9112-ca671baf84c9n%40googlegroups.com?utm_medium=email&utm_source=footer> >>>> . >>>> >>> -- You received this message because you are subscribed to the Google Groups "Prometheus Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to prometheus-users+unsubscr...@googlegroups.com. 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