On 2023-05-10 06:49, Guillaume Quintard wrote:
Hi Jakob,
(Sorry i didn't see that email sooner, it was in my spam folder)
Looking at the log, I'm not sure what varnish should be loud about :-)
204 is a success code, and more importantly it's generated by the
backend, so varnish is happily passing it along.
At the http level, everything looks about right, but I can guess from
your apparent irritation that something wrong one level up, let's try to
debug that.
What kind of response are you expecting, if not a 204? And maybe, what
is that endpoint supposed to do? Given that the method was GET, and that
there's no body, my only guess is that there's something happening with
the TeamCity-AgentSessionId header, maybe?
Is the 27 seconds processing time expected?
Expecting uncachable results that vary with time and are only sometimes
204, and the response time is also somewhat unexpected, but is not
clearly logged (only a Varnish expert like you can decrypt that it is 27
seconds). It is also unclear if Varnish is always receiving those
responses from the backend.
I also expected some other URLs in the log, but don't see them.
Maybe I should find another day to run the experiments again.
Cheers,
On Tue, May 9, 2023, 15:12 Jakob Bohm <jb-varn...@wisemo.com
<mailto:jb-varn...@wisemo.com>> wrote:
Dear Varnish mailing list,
When testing varnish as a reverse proxy for multiple services
including a local JetBrains TeamCity instance, requests to that
teamcity server get corrupted into "204 No Content" replies.
Once again, Varnish fails to say why it is refusing to do its job.
Any sane program should explicitly and loudly report any fatal error
that stops it working. Loudly means the sysadmin or other user
invoking the program receives the exaxt error message by default
instead of something highly indirect, hidden behind a debug option
or otherwisse highly non-obvious.
Here's a relevant clip from the VCL:
# Various top comments
vcl 4.1;
import std;
import proxy;
# Backend sending requests to the teamcity main server
backend teamcity {
.host = "2a01:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx";
.port = "8111";
}
# IP ranges allowed to access the build server and staging server
acl buildtrust {
"127.0.0.0"/8;
"::"/128;
"various others"/??;
}
# IP ranges allowed to attempt login to things that use our common login
# database
acl logintrust {
"various others"/??;
}
sub vcl_recv {
# Happens before we check if we have this in cache already.
#
# Typically you clean up the request here, removing cookies you
don't need,
# rewriting the request, etc.
if (proxy.is_ssl()) {
set req.http.Scheme = "https";
set req.http.ssl-version = proxy.ssl_version();
set req.http.X-Forwarded-Proto = "https";
set req.http.X-SSL-cipher = proxy.ssl_cipher();
std.log("TLS-SSL-VERSION: " + proxy.ssl_version());
} else {
set req.http.X-Forwarded-Proto = req.http.Scheme;
unset req.http.ssl-version;
unset req.http.X-SSL-cipher;
std.log("TLS-SSL-VERSION: none");
}
unset req.http.X-SSL-Subject;
unset req.http.X-SSL-Issuer;
unset req.http.X-SSL-notBefore;
unset req.http.X-SSL-notAfter;
unset req.http.X-SSL-serial;
unset req.http.X-SSL-certificate;
set req.http.X-Forwarded-For = client.ip;
call vcl_req_host;
if (req.url ~ "^/something") {
set req.backend_hint = be1;
} else if (req.url !~ "^/somethingelse" &&
!(client.ip ~ logintrust) &&
!(client.ip ~ buildtrust)) {
# Treat as unknown by redirecting to public website
if ((req.url ~ "^/yeatanother") ||
(req.url ~ "^/yetsomeother")) {
return (synth(752));
} else if (req.url ~ "^/yetsomethird") {
return (synth(753));
}
return (synth(751));
} else if (req.http.Scheme && req.http.Scheme != "https") {
# See example at
https://www.varnish-software.com/developers/tutorials/redirect/
return (synth(750));
} else if (req.url ~ "^/somethingelse") {
set req.backend_hint = be1;
} else if (req.url ~ "^/somethingfourth") {
set req.backend_hint = be2;
} else if (req.url ~ "^/somethingfifth") {
set req.backend_hint = be2;
} else if (!(client.ip ~ buildtrust)) {
# Treat as unknown by redirecting to public website
if ((req.url ~ "^/yeatanother") ||
(req.url ~ "^/yetsomeother")) {
return (synth(752));
} else if (req.url ~ "^/yetsomethird") {
return (synth(753));
}
return (synth(751));
} else if (req.url ~ "^/teamcity") {
set req.backend_hint= teamcity;
return (pass);
# } else if (req.http.host ~ "^somethingsixths") {
# set req.backend_hint= be4;
} else {
set req.backend_hint = be5;
}
call vcl_req_method;
call vcl_req_authorization;
call vcl_req_cookie;
return (hash);
}
sub vcl_backend_response {
# Happens after we have read the response headers from the
backend.
#
# Here you clean the response headers, removing silly Set-Cookie
headers
# and other mistakes your backend does.
# The Java webserver in teamcity is incompatible with varnish
connection
# pooling
if (beresp.backend == teamcity) {
if (beresp.http.Connection &&
beresp.http.Connection !~ "keep-alive") {
set beresp.http.Connection += ", close";
} else {
set beresp.http.Connection = "close";
}
}
}
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
First 43 lines of varnishlog -v 2>&1
* << BeReq >> 9
- 9 Begin b bereq 8 pass
- 9 VCL_use b boot
- 9 Timestamp b Start: 1681484803.177212 0.000000
0.000000
- 9 BereqMethod b GET
- 9 BereqURL b /teamcity/app/agents/v1/commands/next
- 9 BereqProtocol b HTTP/1.1
- 9 BereqHeader b TeamCity-AgentSessionId:
L6juFAAt1awJDt6UKToPIxQq7wpBF89C
- 9 BereqHeader b User-Agent: TeamCity Agent 2021.2.3
- 9 BereqHeader b Host: vmachine.example.com
<http://vmachine.example.com>
- 9 BereqHeader b Via: 1.1 vmachine (Varnish/7.2)
- 9 BereqHeader b Scheme: https
- 9 BereqHeader b ssl-version: TLSv1.3
- 9 BereqHeader b X-Forwarded-Proto: https
- 9 BereqHeader b X-SSL-cipher: TLS_AES_256_GCM_SHA384
- 9 BereqHeader b X-Forwarded-For: 192.168.2.112
- 9 BereqHeader b X-Varnish: 9
- 9 VCL_call b BACKEND_FETCH
- 9 VCL_return b fetch
- 9 Timestamp b Fetch: 1681484803.177227 0.000014
0.000014
- 9 Timestamp b Connected: 1681484803.177603 0.000390
0.000375
- 9 BackendOpen b 24 teamcity
2a01:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx 8111 2a01:yyyy:yyyy:yyyy::yyyy
59548 connect
- 9 Timestamp b Bereq: 1681484803.177645 0.000432
0.000042
- 9 BerespReason b No Content
- 9 Timestamp b Beresp: 1681484830.672487 27.495274
27.494842
- 9 BerespProtocol b HTTP/1.1
- 9 BerespStatus b 204
- 9 BerespReason b No Content
- 9 BerespHeader b TeamCity-Node-Id: MAIN_SERVER
- 9 BerespHeader b Date: Fri, 14 Apr 2023 15:07:10 GMT
- 9 VCL_call b BACKEND_RESPONSE
- 9 BerespHeader b Connection: close
- 9 VCL_return b deliver
- 9 Timestamp b Process: 1681484830.672563 27.495350
0.000075
- 9 Filters b
- 9 Storage b malloc Transient
- 9 Fetch_Body b 0 none -
- 9 BackendClose b 24 teamcity close Backend/VCL requested
close
- 9 Timestamp b BerespBody: 1681484830.672926 27.495713
0.000362
- 9 Length b 0
- 9 BereqAcct b 345 0 345 85 0 85
- 9 End b
Enjoy
Jakob
--
Jakob Bohm, CIO, Partner, WiseMo A/S. https://www.wisemo.com
Transformervej 29, 2860 Søborg, Denmark. Direct +45 31 13 16 10
This public discussion message is non-binding and may contain errors.
WiseMo - Remote Service Management for PCs, Phones and Embedded
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