feat: Remote interface interoperate distributed computing resources

* make BUILD_REMOTE=1 to build libdcurl.so and remote-worker
* make BUILD_REMOTE=1 check with RabbitMQ broker and remote-worker
* RPC with exclusive callback queues with TTL property
* AMQP connection management for multiple threads
* Implement local fallback PoW when remote interface fails

Related #137

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "deps/libtuv"]
 	path = deps/libtuv
 	url = https://github.com/DLTcollab/libtuv.git
+[submodule "deps/rabbitmq-c"]
+	path = deps/rabbitmq-c
+	url = https://github.com/alanxz/rabbitmq-c.git

Makefile

@@ -72,6 +72,10 @@ ifeq ("$(BUILD_FPGA_ACCEL)","1")
 CFLAGS += -DENABLE_FPGA_ACCEL
 endif
 
+ifeq ("$(BUILD_REMOTE)","1")
+CFLAGS += -DENABLE_REMOTE
+endif
+
 ifeq ("$(BUILD_JNI)","1")
 include mk/java.mk
 endif
@@ -99,6 +103,9 @@ PREQ := config $(TESTS) $(LIBS)
 ifeq ("$(BUILD_JNI)","1")
 PREQ += $(JARS)
 endif
+ifeq ("$(BUILD_REMOTE)", "1")
+PREQ += $(OUT)/remote-worker
+endif
 
 all: $(PREQ)
 .DEFAULT_GOAL := all
@@ -140,23 +147,36 @@ OBJS += \
 	pow_fpga_accel.o
 endif
 
+ifeq ("$(BUILD_REMOTE)", "1")
+OBJS += \
+	remote_common.o \
+	remote_interface.o
+
+WORKER_OBJS := $(addprefix $(OUT)/worker-,$(filter-out remote_interface.o, $(OBJS)))
+WORKER_CFLAGS := $(filter-out -DENABLE_REMOTE, $(CFLAGS))
+endif
+
 OBJS := $(addprefix $(OUT)/, $(OBJS))
 
 $(OUT)/test-%.o: tests/test-%.c $(LIBTUV_PATH)/include
 	$(VECHO) "  CC\t$@\n"
 	$(Q)$(CC) -o $@ $(CFLAGS) -I $(SRC) $(LIBTUV_INCLUDE) -c -MMD -MF $@.d $<
 
-$(OUT)/%.o: $(SRC)/%.c $(LIBTUV_PATH)/include
+$(OUT)/%.o: $(SRC)/%.c $(LIBTUV_PATH)/include $(LIBRABBITMQ_PATH)/build/include
 	$(VECHO) "  CC\t$@\n"
-	$(Q)$(CC) -o $@ $(CFLAGS) $(LIBTUV_INCLUDE) -c -MMD -MF $@.d $<
+	$(Q)$(CC) -o $@ $(CFLAGS) $(LIBTUV_INCLUDE) $(LIBRABBITMQ_INCLUDE) -c -MMD -MF $@.d $<
 
-$(OUT)/test-%: $(OUT)/test-%.o $(OBJS) $(LIBTUV_LIBRARY)
+$(OUT)/test-%: $(OUT)/test-%.o $(OBJS) $(LIBTUV_LIBRARY) $(LIBRABBITMQ_LIBRARY)
 	$(VECHO) "  LD\t$@\n"
-	$(Q)$(CC) -o $@ $^ $(LDFLAGS)
+	$(Q)$(CC) -o $@ $^ $(LDFLAGS) $(LIBRABBITMQ_LINK)
 
-$(OUT)/libdcurl.so: $(OBJS) $(LIBTUV_LIBRARY)
+$(OUT)/libdcurl.so: $(OBJS) $(LIBTUV_LIBRARY) $(LIBRABBITMQ_LIBRARY)
 	$(VECHO) "  LD\t$@\n"
-	$(Q)$(CC) -shared -o $@ $^ $(LDFLAGS)
+	$(Q)$(CC) -shared -o $@ $^ $(LDFLAGS) $(LIBRABBITMQ_LINK)
+
+ifeq ("$(BUILD_REMOTE)", "1")
+include mk/remote.mk
+endif
 
 include mk/common.mk
 

mk/defs.mk

@@ -19,6 +19,9 @@ BUILD_GPU ?= 0
 # Build FPGA backend or not
 BUILD_FPGA_ACCEL ?= 0
 
+# Build facilities of remote procedure calls
+BUILD_REMOTE ?= 0
+
 # Build JNI glue as the bridge between dcurl and IRI
 BUILD_JNI ?= 0
 

mk/remote.mk

@@ -0,0 +1,8 @@
+# Build remote-worker
+$(OUT)/worker-%.o: $(SRC)/%.c $(LIBTUV_PATH)/include $(LIBRABBITMQ_PATH)/build/include
+	$(VECHO) "  CC\t$@\n"
+	$(Q)$(CC) -o $@ $(WORKER_CFLAGS) $(LIBTUV_INCLUDE) $(LIBRABBITMQ_INCLUDE) -c -MMD -MF $@.d $<
+
+$(OUT)/remote-worker: $(OUT)/remote_worker.o $(WORKER_OBJS) $(LIBTUV_LIBRARY) $(LIBRABBITMQ_LIBRARY)
+	$(VECHO) "  LD\t$@\n"
+	$(Q)$(CC) -o $@ $^ $(LDFLAGS) $(LIBRABBITMQ_LINK)

mk/submodule.mk

@@ -26,3 +26,34 @@ $(LIBTUV_PATH)/include:
 
 $(LIBTUV_LIBRARY):
 	$(MAKE) -C $(LIBTUV_PATH) TUV_BUILD_TYPE=release TUV_CREATE_PIC_LIB=yes TUV_PLATFORM=$(LIBTUV_PLATFORM) TUV_BOARD=$(LIBTUV_BOARD)
+
+# librabbitmq related variables
+LIBRABBITMQ_PATH = deps/rabbitmq-c
+LIBRABBITMQ_INCLUDE := -I $(LIBRABBITMQ_PATH)/build/include
+LIBRABBITMQ_LIB_PATH := $(LIBRABBITMQ_PATH)/build/librabbitmq/
+ifeq ($(UNAME_S),darwin)
+    # macOS
+    LIBRABBITMQ_LINK := -Wl,-rpath,$(LIBRABBITMQ_LIB_PATH) -L$(LIBRABBITMQ_LIB_PATH) -lrabbitmq
+    LIBRABBITMQ_LIBRARY := $(LIBRABBITMQ_LIB_PATH)/librabbitmq.dylib
+else
+    LIBRABBITMQ_LINK := -Wl,-rpath=$(LIBRABBITMQ_LIB_PATH) -L$(LIBRABBITMQ_LIB_PATH) -lrabbitmq
+    LIBRABBITMQ_LIBRARY := $(LIBRABBITMQ_LIB_PATH)/librabbitmq.so
+endif
+
+$(LIBRABBITMQ_PATH)/build/include:
+	git submodule update --init $(LIBRABBITMQ_PATH)
+	mkdir $(LIBRABBITMQ_PATH)/build
+ifeq ($(UNAME_S),darwin)
+	# macOS
+	cd $(LIBRABBITMQ_PATH)/build && \
+         cmake -DOPENSSL_ROOT_DIR=/usr/local/opt/openssl/ -DCMAKE_INSTALL_PREFIX=. .. && \
+         cmake --build . --target install
+else
+	cd $(LIBRABBITMQ_PATH)/build && \
+         cmake -DCMAKE_INSTALL_PREFIX=. .. && \
+         cmake --build . --target install
+endif
+
+$(LIBRABBITMQ_LIBRARY):
+	cd $(LIBRABBITMQ_PATH)/build && \
+         cmake --build .

src/dcurl.c

@@ -15,6 +15,9 @@
 #if defined(ENABLE_FPGA_ACCEL)
 #include "pow_fpga_accel.h"
 #endif
+#if defined(ENABLE_REMOTE)
+#include "remote_interface.h"
+#endif
 #include "implcontext.h"
 #include "trinary.h"
 #include "uv.h"
@@ -48,6 +51,11 @@ extern ImplContext PoWCL_Context;
 extern ImplContext PoWFPGAAccel_Context;
 #endif
 
+#if defined(ENABLE_REMOTE)
+extern RemoteImplContext Remote_Context;
+static uv_sem_t notify_remote;
+#endif
+
 bool dcurl_init()
 {
     bool ret = true;
@@ -68,6 +76,11 @@ bool dcurl_init()
     ret &= registerImplContext(&PoWFPGAAccel_Context);
 #endif
 
+#if defined(ENABLE_REMOTE)
+    ret &= initializeRemoteContext(&Remote_Context);
+    uv_sem_init(&notify_remote, 0);
+#endif
+
     uv_sem_init(&notify, 0);
     return isInitialized = ret;
 }
@@ -77,6 +90,10 @@ void dcurl_destroy()
     ImplContext *impl = NULL;
     struct list_head *p;
 
+#if defined(ENABLE_REMOTE)
+    destroyRemoteContext(&Remote_Context);
+#endif
+
     list_for_each (p, &IMPL_LIST) {
         impl = list_entry(p, ImplContext, list);
         destroyImplContext(impl);
@@ -96,6 +113,28 @@ int8_t *dcurl_entry(int8_t *trytes, int mwm, int threads)
     if (!isInitialized)
         return NULL;
 
+#if defined(ENABLE_REMOTE)
+    do {
+        if (enterRemoteContext(&Remote_Context)) {
+            pow_ctx = getRemoteContext(&Remote_Context, trytes, mwm);
+            goto remote_pow;
+        }
+        uv_sem_wait(&notify_remote);
+    } while (1);
+
+remote_pow:
+    if (!doRemoteContext(&Remote_Context, pow_ctx)) {
+        goto local_pow;
+    } else {
+        res = getRemoteResult(&Remote_Context, pow_ctx);
+    }
+    freeRemoteContext(&Remote_Context, pow_ctx);
+    exitRemoteContext(&Remote_Context);
+    uv_sem_post(&notify_remote);
+    return res;
+
+local_pow:
+#endif
     do {
         list_for_each (p, &IMPL_LIST) {
             impl = list_entry(p, ImplContext, list);