nghttpx: Add healthmon parameter to -f option to enable health monitor mode

src/CMakeLists.txt

@@ -110,6 +110,7 @@ if(ENABLE_APP)
     shrpx_signal.cc
     shrpx_router.cc
     shrpx_api_downstream_connection.cc
+    shrpx_health_monitor_downstream_connection.cc
   )
   if(HAVE_SPDYLAY)
     list(APPEND NGHTTPX_SRCS

src/Makefile.am

@@ -133,6 +133,8 @@ NGHTTPX_SRCS = \
 	shrpx_signal.cc shrpx_signal.h \
 	shrpx_router.cc shrpx_router.h \
 	shrpx_api_downstream_connection.cc shrpx_api_downstream_connection.h \
+	shrpx_health_monitor_downstream_connection.cc \
+	shrpx_health_monitor_downstream_connection.h \
 	buffer.h memchunk.h template.h allocator.h
 
 if HAVE_SPDYLAY

src/shrpx.cc

@@ -1345,7 +1345,7 @@ Connections:
 
               Default: )" << DEFAULT_DOWNSTREAM_HOST << ","
       << DEFAULT_DOWNSTREAM_PORT << R"(
-  -f, --frontend=(<HOST>,<PORT>|unix:<PATH>)[;no-tls]
+  -f, --frontend=(<HOST>,<PORT>|unix:<PATH>)[[;PARAM]...]
               Set  frontend  host and  port.   If  <HOST> is  '*',  it
               assumes  all addresses  including  both  IPv4 and  IPv6.
               UNIX domain  socket can  be specified by  prefixing path
@@ -1353,6 +1353,9 @@ Connections:
               This  option can  be used  multiple times  to listen  to
               multiple addresses.
 
+              This option  can take  0 or  more parameters,  which are
+              described below.
+
               Optionally, TLS  can be disabled by  specifying "no-tls"
               parameter.  TLS is enabled by default.
 
@@ -1363,6 +1366,11 @@ Connections:
               break your services,  or expose confidential information
               to the outside the world.
 
+              To  make  this  frontend  as  health  monitor  endpoint,
+              specify  "healthmon"  parameter.   This is  disabled  by
+              default.  Any  requests which come through  this address
+              are replied with 200 HTTP status, without no body.
+
               Default: *,3000
   --backlog=<N>
               Set listen backlog size.

src/shrpx_client_handler.cc

@@ -49,6 +49,7 @@
 #include "shrpx_http2_session.h"
 #include "shrpx_connect_blocker.h"
 #include "shrpx_api_downstream_connection.h"
+#include "shrpx_health_monitor_downstream_connection.h"
 #ifdef HAVE_SPDYLAY
 #include "shrpx_spdy_upstream.h"
 #endif // HAVE_SPDYLAY
@@ -899,6 +900,8 @@ ClientHandler::get_downstream_connection(Downstream *downstream) {
   switch (faddr_->alt_mode) {
   case ALTMODE_API:
     return make_unique<APIDownstreamConnection>(worker_);
+  case ALTMODE_HEALTHMON:
+    return make_unique<HealthMonitorDownstreamConnection>();
   }
 
   // Fast path.  If we have one group, it must be catch-all group.

src/shrpx_config.cc

@@ -630,6 +630,8 @@ int parse_upstream_params(UpstreamParams &out, const StringRef &src_params) {
       out.tls = false;
     } else if (util::strieq_l("api", param)) {
       out.alt_mode = ALTMODE_API;
+    } else if (util::strieq_l("healthmon", param)) {
+      out.alt_mode = ALTMODE_HEALTHMON;
     } else if (!param.empty()) {
       LOG(ERROR) << "frontend: " << param << ": unknown keyword";
       return -1;

src/shrpx_config.h

@@ -321,6 +321,8 @@ enum UpstreamAltMode {
   ALTMODE_NONE,
   // API processing mode
   ALTMODE_API,
+  // Health monitor mode
+  ALTMODE_HEALTHMON,
 };
 
 struct UpstreamAddr {

src/shrpx_health_monitor_downstream_connection.cc

@@ -0,0 +1,107 @@
+/*
+ * nghttp2 - HTTP/2 C Library
+ *
+ * Copyright (c) 2016 Tatsuhiro Tsujikawa
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#include "shrpx_health_monitor_downstream_connection.h"
+
+#include "shrpx_client_handler.h"
+#include "shrpx_upstream.h"
+#include "shrpx_downstream.h"
+//#include "shrpx_connection_handler.h"
+
+namespace shrpx {
+
+HealthMonitorDownstreamConnection::HealthMonitorDownstreamConnection() {}
+
+HealthMonitorDownstreamConnection::~HealthMonitorDownstreamConnection() {}
+
+int HealthMonitorDownstreamConnection::attach_downstream(
+    Downstream *downstream) {
+  if (LOG_ENABLED(INFO)) {
+    DCLOG(INFO, this) << "Attaching to DOWNSTREAM:" << downstream;
+  }
+
+  downstream_ = downstream;
+
+  return 0;
+}
+
+void HealthMonitorDownstreamConnection::detach_downstream(
+    Downstream *downstream) {
+  if (LOG_ENABLED(INFO)) {
+    DCLOG(INFO, this) << "Detaching from DOWNSTREAM:" << downstream;
+  }
+  downstream_ = nullptr;
+}
+
+int HealthMonitorDownstreamConnection::push_request_headers() { return 0; }
+
+int HealthMonitorDownstreamConnection::push_upload_data_chunk(
+    const uint8_t *data, size_t datalen) {
+  return 0;
+}
+
+int HealthMonitorDownstreamConnection::end_upload_data() {
+  auto upstream = downstream_->get_upstream();
+  auto &resp = downstream_->response();
+
+  resp.http_status = 200;
+
+  resp.fs.add_header_token(StringRef::from_lit("content-length"),
+                           StringRef::from_lit("0"), false,
+                           http2::HD_CONTENT_LENGTH);
+
+  if (upstream->send_reply(downstream_, nullptr, 0) != 0) {
+    return -1;
+  }
+
+  return 0;
+}
+
+void HealthMonitorDownstreamConnection::pause_read(IOCtrlReason reason) {}
+
+int HealthMonitorDownstreamConnection::resume_read(IOCtrlReason reason,
+                                                   size_t consumed) {
+  return 0;
+}
+
+void HealthMonitorDownstreamConnection::force_resume_read() {}
+
+int HealthMonitorDownstreamConnection::on_read() { return 0; }
+
+int HealthMonitorDownstreamConnection::on_write() { return 0; }
+
+void HealthMonitorDownstreamConnection::on_upstream_change(Upstream *uptream) {}
+
+bool HealthMonitorDownstreamConnection::poolable() const { return false; }
+
+DownstreamAddrGroup *
+HealthMonitorDownstreamConnection::get_downstream_addr_group() const {
+  return nullptr;
+}
+
+DownstreamAddr *HealthMonitorDownstreamConnection::get_addr() const {
+  return nullptr;
+}
+
+} // namespace shrpx

src/shrpx_health_monitor_downstream_connection.h

@@ -0,0 +1,63 @@
+/*
+ * nghttp2 - HTTP/2 C Library
+ *
+ * Copyright (c) 2016 Tatsuhiro Tsujikawa
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#ifndef SHRPX_HEALTH_MONITOR_DOWNSTREAM_CONNECTION_H
+#define SHRPX_HEALTH_MONITOR_DOWNSTREAM_CONNECTION_H
+
+#include "shrpx_downstream_connection.h"
+
+namespace shrpx {
+
+class Worker;
+
+class HealthMonitorDownstreamConnection : public DownstreamConnection {
+public:
+  HealthMonitorDownstreamConnection();
+  virtual ~HealthMonitorDownstreamConnection();
+  virtual int attach_downstream(Downstream *downstream);
+  virtual void detach_downstream(Downstream *downstream);
+
+  virtual int push_request_headers();
+  virtual int push_upload_data_chunk(const uint8_t *data, size_t datalen);
+  virtual int end_upload_data();
+
+  virtual void pause_read(IOCtrlReason reason);
+  virtual int resume_read(IOCtrlReason reason, size_t consumed);
+  virtual void force_resume_read();
+
+  virtual int on_read();
+  virtual int on_write();
+
+  virtual void on_upstream_change(Upstream *uptream);
+
+  // true if this object is poolable.
+  virtual bool poolable() const;
+
+  virtual DownstreamAddrGroup *get_downstream_addr_group() const;
+  virtual DownstreamAddr *get_addr() const;
+};
+
+} // namespace shrpx
+
+#endif // SHRPX_HEALTH_MONITOR_DOWNSTREAM_CONNECTION_H

src/shrpx_http2_upstream.cc

@@ -415,7 +415,10 @@ void Http2Upstream::initiate_downstream(Downstream *downstream) {
 
   auto &req = downstream->request();
   if (!req.http2_expect_body) {
-    downstream->end_upload_data();
+    rv = downstream->end_upload_data();
+    if (rv != 0) {
+      rst_stream(downstream, NGHTTP2_INTERNAL_ERROR);
+    }
   }
 
   return;
@@ -443,7 +446,10 @@ int on_frame_recv_callback(nghttp2_session *session, const nghttp2_frame *frame,
     if (frame->hd.flags & NGHTTP2_FLAG_END_STREAM) {
       downstream->disable_upstream_rtimer();
 
-      downstream->end_upload_data();
+      if (downstream->end_upload_data() != 0) {
+        upstream->rst_stream(downstream, NGHTTP2_INTERNAL_ERROR);
+      }
+
       downstream->set_request_state(Downstream::MSG_COMPLETE);
     }
 
@@ -465,7 +471,10 @@ int on_frame_recv_callback(nghttp2_session *session, const nghttp2_frame *frame,
     if (frame->hd.flags & NGHTTP2_FLAG_END_STREAM) {
       downstream->disable_upstream_rtimer();
 
-      downstream->end_upload_data();
+      if (downstream->end_upload_data() != 0) {
+        upstream->rst_stream(downstream, NGHTTP2_INTERNAL_ERROR);
+      }
+
       downstream->set_request_state(Downstream::MSG_COMPLETE);
     }
 

src/shrpx_spdy_upstream.cc

@@ -362,7 +362,9 @@ void SpdyUpstream::initiate_downstream(Downstream *downstream) {
 
   auto &req = downstream->request();
   if (!req.http2_expect_body) {
-    downstream->end_upload_data();
+    if (downstream->end_upload_data() != 0) {
+      rst_stream(downstream, SPDYLAY_INTERNAL_ERROR);
+    }
   }
 }
 
@@ -445,7 +447,9 @@ void on_data_recv_callback(spdylay_session *session, uint8_t flags,
     }
 
     downstream->disable_upstream_rtimer();
-    downstream->end_upload_data();
+    if (downstream->end_upload_data() != 0) {
+      upstream->rst_stream(downstream, SPDYLAY_INTERNAL_ERROR);
+    }
     downstream->set_request_state(Downstream::MSG_COMPLETE);
   }
 }