REGTESTS: http-messaging: test the options dropping the HTTP trailers

"option http-drop-request-trailers" and
"option http-drop-response-trailers" had no coverage.

vtest can send HTTP/1 trailers but cannot parse them, so neither end of
the chain may be a vtest HTTP peer when the trailers are expected to be
forwarded: the request side origin is a small haproxy instance, and the
client of the forwarded response side only reads the headers and then
the exact number of remaining bytes.

What actually leaves the proxy is observed at the byte level by two
extra haproxy instances running in TCP mode, one on each side, which
report through their log whether the trailer field name appears in what
they relayed. This gives a positive assertion for both the dropped and
the forwarded case, and the "no option" form is covered as well.

diff --git a/reg-tests/http-messaging/drop_trailers.vtc b/reg-tests/http-messaging/drop_trailers.vtc
new file mode 100644 (file)
index 0000000..73d1349
--- /dev/null
+++ b/reg-tests/http-messaging/drop_trailers.vtc
@@ -0,0 +1,204 @@
+varnishtest "Test the options dropping the HTTP trailers"
+
+# "option http-drop-request-trailers" and
+# "option http-drop-response-trailers" had no coverage.
+#
+# vtest can send HTTP/1 trailers but cannot parse them, so neither end
+# of the chain may be a vtest HTTP peer when the trailers are expected
+# to be forwarded. The messages leaving the proxy under test are
+# therefore observed at the byte level by two extra haproxy instances
+# running in TCP mode, one on each side, and each of them reports
+# through its log whether the trailer field name is present in what it
+# relayed. This gives a positive assertion for both the dropped and the
+# forwarded case.
+
+feature ignore_unknown_macro
+
+syslog Sreq -level info {
+       recv
+       expect ~ "case=drop trailers=- "
+       recv
+       expect ~ "case=keep trailers=yes "
+} -start
+
+syslog Sres -level info {
+       recv
+       expect ~ "case=drop trailers=- "
+       recv
+       expect ~ "case=keep trailers=yes "
+} -start
+
+# the origin of the request side, which unlike a vtest server accepts
+# trailers
+haproxy horigin -conf {
+    global
+    .if feature(THREAD)
+        thread-groups 1
+    .endif
+        chroot /
+
+    defaults
+       mode http
+       timeout connect "${HAPROXY_TEST_TIMEOUT-5s}"
+       timeout client  "${HAPROXY_TEST_TIMEOUT-5s}"
+       timeout server  "${HAPROXY_TEST_TIMEOUT-5s}"
+
+    frontend origin
+       bind "fd@${origin}"
+       # close after the response so that the TCP session of the observer
+       # ends at once instead of lingering until the client timeout
+       option httpclose
+       http-request return status 200
+} -start
+
+# the origin of the response side, which emits the trailers
+server s2 -repeat 2 {
+       rxreq
+       txresp -nolen -hdr "transfer-encoding: chunked"
+       send "5\r\nworld\r\n0\r\nx-rtlr1: rvalue1\r\n\r\n"
+} -start
+
+# request side observer, between the proxy and the origin
+haproxy hreq -conf {
+    global
+    .if feature(THREAD)
+        thread-groups 1
+    .endif
+        chroot /
+       log "${Sreq_addr}:${Sreq_port}" local0 info
+
+    defaults
+       mode tcp
+       log global
+       timeout connect "${HAPROXY_TEST_TIMEOUT-5s}"
+       timeout client  "${HAPROXY_TEST_TIMEOUT-5s}"
+       timeout server  "${HAPROXY_TEST_TIMEOUT-5s}"
+
+    frontend sink
+       bind "fd@${sink}"
+       log-format "case=%[var(txn.case)] trailers=%[var(txn.tlr)] bytes=%B"
+
+       # the rules are replayed as the data arrives, the last evaluation
+       # before the delay expires is the one which gets logged
+       tcp-request inspect-delay 100ms
+       tcp-request content set-var(txn.case) str(drop) if { req.payload(0,0) -m sub "/drop" }
+       tcp-request content set-var(txn.case) str(keep) if { req.payload(0,0) -m sub "/keep" }
+       tcp-request content set-var(txn.tlr)  str(yes)  if { req.payload(0,0) -m sub "x-tlr1" }
+
+       default_backend be
+    backend be
+       server origin ${horigin_origin_addr}:${horigin_origin_port}
+} -start
+
+haproxy h1 -conf {
+    global
+    .if feature(THREAD)
+        thread-groups 1
+    .endif
+        chroot /
+
+    defaults
+       mode http
+       timeout connect "${HAPROXY_TEST_TIMEOUT-5s}"
+       timeout client  "${HAPROXY_TEST_TIMEOUT-5s}"
+       timeout server  "${HAPROXY_TEST_TIMEOUT-5s}"
+
+    # the request side option belongs to the backend
+    frontend fe_req
+       bind "fd@${fereq}"
+       use_backend be_req_drop if { path -m beg /drop }
+       default_backend be_req_keep
+
+    backend be_req_drop
+       option http-drop-request-trailers
+       server origin ${hreq_sink_addr}:${hreq_sink_port}
+
+    backend be_req_keep
+       no option http-drop-request-trailers
+       server origin ${hreq_sink_addr}:${hreq_sink_port}
+
+    # the response side option belongs to the frontend, hence two of them
+    frontend fe_res_drop
+       bind "fd@${feresdrop}"
+       option http-drop-response-trailers
+       default_backend be_res
+
+    frontend fe_res_keep
+       bind "fd@${fereskeep}"
+       default_backend be_res
+
+    backend be_res
+       server s2 ${s2_addr}:${s2_port}
+} -start
+
+# response side observer, between the client and the proxy
+haproxy hres -conf {
+    global
+    .if feature(THREAD)
+        thread-groups 1
+    .endif
+        chroot /
+       log "${Sres_addr}:${Sres_port}" local0 info
+
+    defaults
+       mode tcp
+       log global
+       timeout connect "${HAPROXY_TEST_TIMEOUT-5s}"
+       timeout client  "${HAPROXY_TEST_TIMEOUT-5s}"
+       timeout server  "${HAPROXY_TEST_TIMEOUT-5s}"
+
+    frontend sink_drop
+       bind "fd@${sinkdrop}"
+       log-format "case=drop trailers=%[var(txn.rtlr)] bytes=%B"
+       default_backend be_drop
+    backend be_drop
+       tcp-response inspect-delay 100ms
+       tcp-response content set-var(txn.rtlr) str(yes) if { res.payload(0,0) -m sub "x-rtlr1" }
+       server h1 ${h1_feresdrop_addr}:${h1_feresdrop_port}
+
+    frontend sink_keep
+       bind "fd@${sinkkeep}"
+       log-format "case=keep trailers=%[var(txn.rtlr)] bytes=%B"
+       default_backend be_keep
+    backend be_keep
+       tcp-response inspect-delay 100ms
+       tcp-response content set-var(txn.rtlr) str(yes) if { res.payload(0,0) -m sub "x-rtlr1" }
+       server h1 ${h1_fereskeep_addr}:${h1_fereskeep_port}
+} -start
+
+# the request trailers are dropped on their way to the origin
+client c1 -connect ${h1_fereq_sock} {
+       txreq -req POST -url "/drop" -hdr "transfer-encoding: chunked" -nolen
+       send "5\r\nhello\r\n0\r\nx-tlr1: value1\r\n\r\n"
+       rxresp
+       expect resp.status == 200
+} -run
+
+# and forwarded without the option
+client c2 -connect ${h1_fereq_sock} {
+       txreq -req POST -url "/keep" -hdr "transfer-encoding: chunked" -nolen
+       send "5\r\nhello\r\n0\r\nx-tlr1: value1\r\n\r\n"
+       rxresp
+       expect resp.status == 200
+} -run
+
+# the response trailers are dropped, so the message is one vtest can parse
+client c3 -connect ${hres_sinkdrop_sock} {
+       txreq -url "/res"
+       rxresp
+       expect resp.status == 200
+       expect resp.bodylen == 5
+} -run
+
+# here they are forwarded, so only the headers are parsed and the rest
+# is left to the observer
+client c4 -connect ${hres_sinkkeep_sock} {
+       txreq -url "/res"
+       rxresphdrs
+       expect resp.status == 200
+       # "5\r\nworld\r\n" "0\r\n" "x-rtlr1: rvalue1\r\n" "\r\n"
+       recv 33
+} -run
+
+syslog Sreq -wait
+syslog Sres -wait