rev: async response bodies with DevFdResponse middleware

This new middleware should be a no-op for non-Rev concurrency
models (or by explicitly setting env['rainbows.autochunk'] to
false).

Setting env['rainbows.autochunk'] to true (the default when Rev
is used) allows (e)poll-able IO objects (sockets, pipes) to be
sent asynchronously after app.call(env) returns.

This also has a fortunate side effect of introducing a code path
which allows large, static files to be sent without slurping
them into a Rev IO::Buffer, too.  This new change works even
without the DevFdResponse middleware, so you won't have to
reconfigure your app.

This lets us epoll on response bodies that come in from a pipe
or even a socket and send them either straight through or with
chunked encoding.

18 files changed, 160 insertions, 0 deletions

diff --git a/t/async-response-no-autochunk.ru b/t/async-response-no-autochunk.ru
new file mode 100644
index 0000000..67c6403
--- /dev/null
+++ b/t/async-response-no-autochunk.ru
@@ -0,0 +1,24 @@
+use Rack::Chunked
+use Rainbows::DevFdResponse
+script = <<-EOF
+for i in 0 1 2 3 4 5 6 7 8 9
+do
+        printf '1\r\n%s\r\n' $i
+        sleep 1
+done
+printf '0\r\n\r\n'
+EOF
+
+run lambda { |env|
+  env['rainbows.autochunk'] = false
+  io = IO.popen(script, 'rb')
+  io.sync = true
+  [
+    200,
+    {
+      'Content-Type' => 'text/plain',
+      'Transfer-Encoding' => 'chunked',
+    },
+    io
+  ].freeze
+}
diff --git a/t/async-response.ru b/t/async-response.ru
new file mode 100644
index 0000000..ef76504
--- /dev/null
+++ b/t/async-response.ru
@@ -0,0 +1,13 @@
+use Rack::Chunked
+use Rainbows::DevFdResponse
+run lambda { |env|
+  io = IO.popen('for i in 0 1 2 3 4 5 6 7 8 9; do date; sleep 1; done', 'rb')
+  io.sync = true
+  [
+    200,
+    {
+      'Content-Type' => 'text/plain',
+    },
+    io
+  ].freeze
+}
diff --git a/t/large-file-response.ru b/t/large-file-response.ru
new file mode 100644
index 0000000..90dc6c5
--- /dev/null
+++ b/t/large-file-response.ru
@@ -0,0 +1,13 @@
+# lib-large-file-response will stop running if we're not on Linux here
+use Rack::ContentLength
+use Rack::ContentType
+map "/rss" do
+  run lambda { |env|
+    # on Linux, this is in kilobytes
+    ::File.read("/proc/self/status") =~ /^VmRSS:\s+(\d+)/
+    [ 200, {}, [ ($1.to_i * 1024).to_s ] ]
+  }
+end
+map "/" do
+  run Rack::File.new(Dir.pwd)
+end
diff --git a/t/lib-async-response-no-autochunk.sh b/t/lib-async-response-no-autochunk.sh
new file mode 100644
index 0000000..66be85e
--- /dev/null
+++ b/t/lib-async-response-no-autochunk.sh
@@ -0,0 +1,6 @@
+#!/bin/sh
+CONFIG_RU=async-response-no-autochunk.ru
+. ./lib-async-response.sh
+test x"$(cat $a)" = x0123456789
+test x"$(cat $b)" = x0123456789
+test x"$(cat $c)" = x0123456789
diff --git a/t/lib-async-response.sh b/t/lib-async-response.sh
new file mode 100644
index 0000000..925455b
--- /dev/null
+++ b/t/lib-async-response.sh
@@ -0,0 +1,45 @@
+CONFIG_RU=${CONFIG_RU-'async-response.ru'}
+. ./test-lib.sh
+echo "async response for model=$model"
+eval $(unused_listen)
+rtmpfiles unicorn_config a b c r_err r_out pid curl_err
+
+cat > $unicorn_config <<EOF
+listen "$listen"
+stderr_path "$r_err"
+stdout_path "$r_out"
+pid "$pid"
+Rainbows! { use :$model }
+EOF
+
+# can't load Rack::Lint here since it'll cause Rev to slurp
+rainbows -E none -D $CONFIG_RU -c $unicorn_config
+wait_for_pid $pid
+
+t0=$(date +%s)
+( curl --no-buffer -sSf http://$listen/ 2>> $curl_err | utee $a) &
+( curl --no-buffer -sSf http://$listen/ 2>> $curl_err | utee $b) &
+( curl --no-buffer -sSf http://$listen/ 2>> $curl_err | utee $c) &
+wait
+t1=$(date +%s)
+
+rainbows_pid=$(cat $pid)
+kill -QUIT $rainbows_pid
+elapsed=$(( $t1 - $t0 ))
+echo "elapsed=$elapsed < 30"
+test $elapsed -lt 30
+
+dbgcat a
+dbgcat b
+dbgcat c
+dbgcat r_err
+dbgcat curl_err
+test ! -s $curl_err
+grep Error $r_err && die "errors in $r_err"
+
+while kill -0 $rainbows_pid >/dev/null 2>&1
+do
+        sleep 1
+done
+
+dbgcat r_err
diff --git a/t/lib-large-file-response.sh b/t/lib-large-file-response.sh
new file mode 100644
index 0000000..830812a
--- /dev/null
+++ b/t/lib-large-file-response.sh
@@ -0,0 +1,45 @@
+. ./test-lib.sh
+test -r random_blob || die "random_blob required, run with 'make $0'"
+if ! grep -v ^VmRSS: /proc/self/status >/dev/null 2>&1
+then
+        echo >&2 "skipping, can't read RSS from /proc/self/status"
+        exit 0
+fi
+echo "large file response slurp avoidance for model=$model"
+eval $(unused_listen)
+rtmpfiles unicorn_config tmp r_err r_out pid ok
+
+cat > $unicorn_config <<EOF
+listen "$listen"
+stderr_path "$r_err"
+stdout_path "$r_out"
+pid "$pid"
+Rainbows! { use :$model }
+EOF
+
+# can't load Rack::Lint here since it'll cause Rev to slurp
+rainbows -E none -D large-file-response.ru -c $unicorn_config
+wait_for_pid $pid
+
+random_blob_size=$(wc -c < random_blob)
+curl -v http://$listen/rss
+dbgcat r_err
+rss_before=$(curl -sSfv http://$listen/rss)
+echo "rss_before=$rss_before"
+
+for i in a b c
+do
+        size=$( (curl -sSfv http://$listen/random_blob && echo ok > $ok) | wc -c)
+        test $size -eq $random_blob_size
+        test xok = x$(cat $ok)
+done
+
+dbgcat r_err
+curl -v http://$listen/rss
+rss_after=$(curl -sSfv http://$listen/rss)
+echo "rss_after=$rss_after"
+diff=$(( $rss_after - $rss_before ))
+echo "test diff=$diff < orig=$random_blob_size"
+kill -QUIT $(cat $pid)
+test $diff -le $random_blob_size
+dbgcat r_err
diff --git a/t/t1004-thread-pool-async-response.sh b/t/t1004-thread-pool-async-response.sh
new file mode 120000
index 0000000..15c27db
--- /dev/null
+++ b/t/t1004-thread-pool-async-response.sh
@@ -0,0 +1 @@
+lib-async-response.sh
\ No newline at end of file
diff --git a/t/t1005-thread-pool-large-file-response.sh b/t/t1005-thread-pool-large-file-response.sh
new file mode 120000
index 0000000..37d2877
--- /dev/null
+++ b/t/t1005-thread-pool-large-file-response.sh
@@ -0,0 +1 @@
+lib-large-file-response.sh
\ No newline at end of file
diff --git a/t/t1006-thread-pool-async-response-no-autochunk.sh b/t/t1006-thread-pool-async-response-no-autochunk.sh
new file mode 120000
index 0000000..bb87ca9
--- /dev/null
+++ b/t/t1006-thread-pool-async-response-no-autochunk.sh
@@ -0,0 +1 @@
+lib-async-response-no-autochunk.sh
\ No newline at end of file
diff --git a/t/t2004-thread-spawn-async-response.sh b/t/t2004-thread-spawn-async-response.sh
new file mode 120000
index 0000000..15c27db
--- /dev/null
+++ b/t/t2004-thread-spawn-async-response.sh
@@ -0,0 +1 @@
+lib-async-response.sh
\ No newline at end of file
diff --git a/t/t2005-thread-spawn-large-file-response.sh b/t/t2005-thread-spawn-large-file-response.sh
new file mode 120000
index 0000000..37d2877
--- /dev/null
+++ b/t/t2005-thread-spawn-large-file-response.sh
@@ -0,0 +1 @@
+lib-large-file-response.sh
\ No newline at end of file
diff --git a/t/t2006-thread-spawn-async-response-no-autochunk.sh b/t/t2006-thread-spawn-async-response-no-autochunk.sh
new file mode 120000
index 0000000..bb87ca9
--- /dev/null
+++ b/t/t2006-thread-spawn-async-response-no-autochunk.sh
@@ -0,0 +1 @@
+lib-async-response-no-autochunk.sh
\ No newline at end of file
diff --git a/t/t3004-revactor-async-response.sh b/t/t3004-revactor-async-response.sh
new file mode 120000
index 0000000..15c27db
--- /dev/null
+++ b/t/t3004-revactor-async-response.sh
@@ -0,0 +1 @@
+lib-async-response.sh
\ No newline at end of file
diff --git a/t/t3005-revactor-large-file-response.sh b/t/t3005-revactor-large-file-response.sh
new file mode 100755
index 0000000..ef1a4a3
--- /dev/null
+++ b/t/t3005-revactor-large-file-response.sh
@@ -0,0 +1,2 @@
+#!/bin/sh
+. ./lib-large-file-response.sh
diff --git a/t/t3006-revactor-async-response-no-autochunk.sh b/t/t3006-revactor-async-response-no-autochunk.sh
new file mode 120000
index 0000000..bb87ca9
--- /dev/null
+++ b/t/t3006-revactor-async-response-no-autochunk.sh
@@ -0,0 +1 @@
+lib-async-response-no-autochunk.sh
\ No newline at end of file
diff --git a/t/t4004-rev-async-response.sh b/t/t4004-rev-async-response.sh
new file mode 120000
index 0000000..15c27db
--- /dev/null
+++ b/t/t4004-rev-async-response.sh
@@ -0,0 +1 @@
+lib-async-response.sh
\ No newline at end of file
diff --git a/t/t4005-rev-large-file-response.sh b/t/t4005-rev-large-file-response.sh
new file mode 100755
index 0000000..ef1a4a3
--- /dev/null
+++ b/t/t4005-rev-large-file-response.sh
@@ -0,0 +1,2 @@
+#!/bin/sh
+. ./lib-large-file-response.sh
diff --git a/t/t4006-rev-async-response-no-autochunk.sh b/t/t4006-rev-async-response-no-autochunk.sh
new file mode 120000
index 0000000..bb87ca9
--- /dev/null
+++ b/t/t4006-rev-async-response-no-autochunk.sh
@@ -0,0 +1 @@
+lib-async-response-no-autochunk.sh
\ No newline at end of file