Merge branch 'main' into wip-thrift

CMakeLists.txt

@@ -161,12 +161,16 @@ option(WITH_PROMETHEUS "Whether to include the Prometheus Client in the SDK"
 option(WITH_ELASTICSEARCH
        "Whether to include the Elasticsearch Client in the SDK" OFF)
 
+option(WITH_ZPAGES "Whether to include the Zpages Server in the SDK" OFF)
+
 option(WITH_JAEGER "Whether to include the Jaeger exporter" OFF)
 
 option(WITH_NO_GETENV "Whether the platform supports environment variables" OFF)
 
 option(BUILD_TESTING "Whether to enable tests" ON)
 
+option(BUILD_W3CTRACECONTEXT_TEST "Whether to build w3c trace context" OFF)
+
 if(WITH_NO_GENENV)
   add_definitions(-DNO_GETENV)
 endif()
@@ -251,29 +255,41 @@ endif()
 # GNUInstallDirs.
 include(GNUInstallDirs)
 
-if(NOT WITH_API_ONLY)
+if((NOT WITH_API_ONLY)
+   OR WITH_ELASTICSEARCH
+   OR WITH_ZIPKIN
+   OR WITH_OTLP
+   OR WITH_OTLP_HTTP
+   OR WITH_ZPAGES
+   OR BUILD_W3CTRACECONTEXT_TEST
+   OR WITH_ETW)
   # nlohmann_json package is required for most SDK build configurations
   find_package(nlohmann_json QUIET)
   if(NOT nlohmann_json_FOUND)
-    message("Using local nlohmann::json from submodule")
-    set(JSON_BuildTests
-        OFF
-        CACHE INTERNAL "")
-    set(JSON_Install
-        ON
-        CACHE INTERNAL "")
-    if(EXISTS ${PROJECT_SOURCE_DIR}/third_party/nlohmann-json)
-      # This option allows to link nlohmann_json::nlohmann_json target
-      add_subdirectory(${PROJECT_SOURCE_DIR}/third_party/nlohmann-json)
-      # This option allows to add header to include directories
-      include_directories(
-        ${PROJECT_SOURCE_DIR}/third_party/nlohmann-json/single_include)
+    if(EXISTS ${PROJECT_SOURCE_DIR}/.git)
+      message("Trying to use local nlohmann::json from submodule")
+      set(JSON_BuildTests
+          OFF
+          CACHE INTERNAL "")
+      set(JSON_Install
+          ON
+          CACHE INTERNAL "")
+      if(EXISTS ${PROJECT_SOURCE_DIR}/third_party/nlohmann-json/CMakeLists.txt)
+        # This option allows to link nlohmann_json::nlohmann_json target
+        add_subdirectory(${PROJECT_SOURCE_DIR}/third_party/nlohmann-json)
+        # This option allows to add header to include directories
+        include_directories(
+          ${PROJECT_SOURCE_DIR}/third_party/nlohmann-json/single_include)
+      else()
+        message(
+          FATAL_ERROR
+            "\nnlohmann_json package was not found. Please either provide it manually or clone with submodules. "
+            "To initialize, fetch and checkout any nested submodules, you can use the following command:\n"
+            "git submodule update --init --recursive")
+      endif()
     else()
-      message(
-        FATAL_ERROR
-          "\nnlohmann_json package was not found. Please either provide it manually or clone with submodules. "
-          "To initialize, fetch and checkout any nested submodules, you can use the following command:\n"
-          "git submodule update --init --recursive")
+      # Let's fail with default find_package error
+      find_package(nlohmann_json REQUIRED)
     endif()
   else()
     message("Using external nlohmann::json")

CONTRIBUTING.md

@@ -97,6 +97,13 @@ git commit
 git push fork feature
 ```
 
+If you made changes to the Markdown documents (`*.md` files), install the latest
+[`markdownlint-cli`](https://github.com/igorshubovych/markdownlint-cli) and run:
+
+```sh
+markdownlint .
+```
+
 Open a pull request against the main `opentelemetry-cpp` repo.
 
 To run tests locally, please read the [CI instructions](ci/README.md).
@@ -144,6 +151,14 @@ If none of the above worked and the PR has been stuck for more than 2 weeks, the
 owner should bring it to the OpenTelemetry C++ SIG meeting. See
 [README.md](README.md#contributing) for the meeting link.
 
+## Design Choices
+
+As with other OpenTelemetry clients, opentelemetry-cpp follows the
+[opentelemetry-specification](https://github.com/open-telemetry/opentelemetry-specification).
+
+It's especially valuable to read through the [library
+guidelines](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/library-guidelines.md).
+
 ## Useful Resources
 
 Hi! If you’re looking at this document, these resources will provide you the
@@ -168,43 +183,13 @@ the C++ repository.
   * The OpenTelemetry Specification describes the requirements and expectations
     of for all OpenTelemetry implementations.
 
-* Read through the [OpenTelemetry
-  Collector](https://github.com/open-telemetry/opentelemetry-collector) GitHub
-  repository.
-  * This repository has a lot of good information surrounding the OpenTelemetry
-    ecosystem. At the top of the
-    **[readme](https://github.com/open-telemetry/opentelemetry-collector/blob/main/README.md)**,
-    there are multiple links that give newcomers a good idea of what the project
-    is about and how to get involved in it.
-* Read through the OpenTelemetry Python documentation
+* Read through the OpenTelemetry C++ documentation
   * The
-    [API](https://opentelemetry-python.readthedocs.io/en/stable/api/api.html)
+    [API](https://opentelemetry-cpp.readthedocs.io/en/latest/api/api.html)
     and
-    [SDK](https://opentelemetry-python.readthedocs.io/en/stable/sdk/sdk.html)
+    [SDK](https://opentelemetry-cpp.readthedocs.io/en/latest/sdk/sdk.html)
     documentation provides a lot of information on what the classes and their
-    functions are used for. Since there is currently minimal documentation for
-    C++, use the Python repository’s extensive documentation to learn more about
-    how the API and SDK work.
-
-### Code Examples
-
-* Follow the [simple trace
-  example](https://github.com/open-telemetry/opentelemetry-cpp/pull/92) for an
-  introduction to basic OpenTelemetry functionality in C++. Currently the
-  example can be found in [PR
-  #94](https://github.com/open-telemetry/opentelemetry-cpp/pull/94).
-
-* Read through the [Java Quick-Start
-  Guide](https://github.com/open-telemetry/opentelemetry-java/blob/main/QUICKSTART.md).
-  This shows you how the classes and functions will interact in simple and easy
-  to digest examples.
-* Take a look at this [Java SDK
-  example](https://github.com/open-telemetry/opentelemetry-java/tree/main/examples/sdk-usage).
-  This shows a good use case of the SDK using stdout exporter.
-* Take a look at the [Java Jaeger
-  example](https://github.com/open-telemetry/opentelemetry-java/tree/main/examples/jaeger).
-  This provides a brief introduction to the Jaeger exporter, its interface, and
-  how to interact with the service.
+    functions are used for.
 
 Please contribute! You’re welcome to add more information if you come across any
 helpful resources.

README.md

@@ -50,7 +50,7 @@ of the current project.
 
 | Platform                                                            |   Build type  |
 |---------------------------------------------------------------------|---------------|
-| ubuntu-18.04 (Default GCC Compiler - 7.5.0)                         | CMake, Bazel  |
+| ubuntu-20.04 (Default GCC Compiler - 9.3.0)                         | CMake, Bazel  |
 | ubuntu-18.04 (GCC 4.8 with -std=c++11 flag)                         | CMake [1]     |
 | ubuntu-20.04 (Default GCC Compiler - 9.3.0 with -std=c++20 flags)   | CMake, Bazel  |
 | macOS 10.15 (Xcode 12.2)                                            | Bazel         |

docs/public/sdk/GettingStarted.rst

@@ -66,7 +66,7 @@ OpenTelemetry offers six tracing exporters out of the box:
 
     // otlp http exporter
     opentelemetry::exporter::otlp::OtlpHttpExporterOptions opts;
-    opts.url = "http://localhost:4317/v1/traces";
+    opts.url = "http://localhost:4318/v1/traces";
     auto otlp_http_exporter =
         std::unique_ptr<sdktrace::SpanExporter>(new opentelemetry::exporter::otlp::OtlpHttpExporter(opts));
 

examples/otlp/README.md

@@ -32,19 +32,18 @@ OpenTelemetry Collector with an OTLP receiver by running:
 - On Unix based systems use:
 
 ```console
-docker run --rm -it -p 4317:4317 -p 55681:55681 -v $(pwd)/examples/otlp:/cfg otel/opentelemetry-collector:0.19.0 --config=/cfg/opentelemetry-collector-config/config.dev.yaml
+docker run --rm -it -p 4317:4317 -p 4318:4318 -v $(pwd)/examples/otlp:/cfg otel/opentelemetry-collector:0.19.0 --config=/cfg/opentelemetry-collector-config/config.dev.yaml
 ```
 
 - On Windows use:
 
 ```console
-docker run --rm -it -p 4317:4317 -p 55681:55681 -v "%cd%/examples/otlp":/cfg otel/opentelemetry-collector:0.19.0 --config=/cfg/opentelemetry-collector-config/config.dev.yaml
+docker run --rm -it -p 4317:4317 -p 4318:4318 -v "%cd%/examples/otlp":/cfg otel/opentelemetry-collector:0.19.0 --config=/cfg/opentelemetry-collector-config/config.dev.yaml
 ```
 
-Note that the OTLP exporter connects to the Collector at `localhost:4317` by
-default. This can be changed with first argument from command-line, for example:
+Note that the OTLP gRPC and HTTP exporters connects to the Collector at `localhost:4317` and `localhost:4318:/v1/traces` respectively. This can be changed with first argument from command-line, for example:
 `./example_otlp_grpc gateway.docker.internal:4317` and
-`./example_otlp_http gateway.docker.internal:55681/v1/traces`.
+`./example_otlp_http gateway.docker.internal:4318/v1/traces`.
 
 Once you have the Collector running, see
 [CONTRIBUTING.md](../../CONTRIBUTING.md) for instructions on building and

examples/otlp/opentelemetry-collector-config/config.dev.yaml

@@ -7,7 +7,7 @@ receivers:
       grpc:
         endpoint: 0.0.0.0:4317
       http:
-        endpoint: "0.0.0.0:55681"
+        endpoint: "0.0.0.0:4318"
         cors_allowed_origins:
         - '*'
 service:

exporters/etw/include/opentelemetry/exporters/etw/etw_logger.h

@@ -76,7 +76,7 @@ class Logger : public logs::Logger
   {
     static ETWProvider instance;  // C++11 magic static
     return instance;
-  };
+  }
 
   /**
    * @brief Init a reference to etw::ProviderHandle