Add pubsub samples to SDK (#82)

Move C++ pub-sub samples from CRT to SDK.

Author: graebm

CMakeLists.txt

@@ -1,6 +1,7 @@
 cmake_minimum_required(VERSION 3.1)
 
 option(BUILD_DEPS "Builds aws common runtime dependencies as part of build, only do this if you don't want to control your dependency chain." OFF)
+option(BUILD_SAMPLES "Build samples as part of the build" ON)
 
 if (DEFINED CMAKE_PREFIX_PATH)
     file(TO_CMAKE_PATH "${CMAKE_PREFIX_PATH}" CMAKE_PREFIX_PATH)
@@ -115,8 +116,11 @@ find_package(aws-crt-cpp REQUIRED)
 add_subdirectory(jobs)
 add_subdirectory(shadow)
 add_subdirectory(discovery)
-add_subdirectory(samples/jobs/describe_job_execution)
-add_subdirectory(samples/shadow/shadow_sync)
-add_subdirectory(samples/greengrass/basic_discovery)
-
 
+if (BUILD_SAMPLES)
+    add_subdirectory(samples/mqtt/basic_pub_sub)
+    add_subdirectory(samples/mqtt/raw_pub_sub)
+    add_subdirectory(samples/jobs/describe_job_execution)
+    add_subdirectory(samples/shadow/shadow_sync)
+    add_subdirectory(samples/greengrass/basic_discovery)
+endif()

README.md

@@ -46,6 +46,54 @@ cmake --build . --target install
 ```
 # Samples
 
+## Basic MQTT Pub-Sub
+
+This sample uses the
+[Message Broker](https://docs.aws.amazon.com/iot/latest/developerguide/iot-message-broker.html)
+for AWS IoT to send and receive messages through an MQTT connection.
+On startup, the device connects to the server and subscribes to a topic.
+
+The terminal prompts the user for input. Type something and press enter to publish a message to the topic.
+Since the sample is subscribed to the same topic, it will also receive the message back from the server.
+Type `quit` and press enter to end the sample.
+
+Source: `samples/mqtt/basic_pub_sub`
+
+Your Thing's
+[Policy](https://docs.aws.amazon.com/iot/latest/developerguide/iot-policies.html)
+must provide privileges for this sample to connect, subscribe, publish,
+and receive.
+
+```json
+{
+    "Effect": "Allow",
+    "Action": [
+        "iot:Receive",
+        "iot:Publish"
+    ],
+    "Resource": [
+        "arn:aws:iot:<your-region>:<your-id>:topic/a/b"
+    ],
+},
+{
+    "Effect": "Allow",
+    "Action": [
+        "iot:Subscribe"
+    ],
+    "Resource": [
+        "arn:aws:iot:<your-region>:<your-id>:topicfilter/a/b"
+    ]
+}
+```
+
+## Raw MQTT Pub-Sub
+This sample is similar to the Basic Pub-Sub, but the connection setup is more manual.
+This is a starting point for using custom
+[Configurable Endpoints](https://docs.aws.amazon.com/iot/latest/developerguide/iot-custom-endpoints-configurable.html).
+
+source: `samples/mqtt/raw_pub_sub`
+
+
 ## Shadow
 
 This sample uses the AWS IoT

samples/mqtt/basic_pub_sub/CMakeLists.txt

@@ -0,0 +1,30 @@
+project(basic-pub-sub CXX)
+
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_INSTALL_PREFIX}/lib/cmake")
+
+file(GLOB PUB_SUB_SRC
+       "*.cpp"
+)
+
+set(PUB_SUB_PROJECT_NAME basic-pub-sub)
+add_executable(${PUB_SUB_PROJECT_NAME} ${PUB_SUB_SRC})
+set_target_properties(${PUB_SUB_PROJECT_NAME} PROPERTIES LINKER_LANGUAGE CXX)
+
+set(CMAKE_C_FLAGS_DEBUGOPT "")
+
+#set warnings
+if (MSVC)
+    target_compile_options(${PUB_SUB_PROJECT_NAME} PRIVATE /W4 /WX /wd4068)
+else ()
+    target_compile_options(${PUB_SUB_PROJECT_NAME} PRIVATE -Wall -Wno-long-long -pedantic -Werror)
+endif ()
+
+if (CMAKE_BUILD_TYPE STREQUAL "" OR CMAKE_BUILD_TYPE MATCHES Debug)
+    target_compile_definitions(${PUB_SUB_PROJECT_NAME} PRIVATE "-DDEBUG_BUILD")
+endif ()
+
+target_include_directories(${PUB_SUB_PROJECT_NAME} PUBLIC
+        $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
+        $<INSTALL_INTERFACE:include>)
+
+target_link_libraries(${PUB_SUB_PROJECT_NAME} AWS::aws-crt-cpp)