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nikhilbhatia08nikhilbhatia08
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[SDK] Implementation of container resource as per semconv (open-telemetry#3572)
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-4
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12 files changed

+329
-4
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‎CMakeLists.txt‎

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@@ -261,6 +261,9 @@ option(WITH_METRICS_EXEMPLAR_PREVIEW
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option(WITH_THREAD_INSTRUMENTATION_PREVIEW
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"Whether to enable thread instrumentation" OFF)
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option(WITH_RESOURCE_DETECTORS_PREVIEW
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"Whether to enable inbuilt resource detectors" OFF)
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option(OPENTELEMETRY_SKIP_DYNAMIC_LOADING_TESTS
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"Whether to build test libraries that are always linked as shared libs"
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OFF)
@@ -645,6 +648,9 @@ if(NOT WITH_API_ONLY)
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add_subdirectory(sdk)
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add_subdirectory(ext)
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add_subdirectory(exporters)
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if(WITH_RESOURCE_DETECTORS_PREVIEW)
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add_subdirectory(resource_detectors)
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endif()
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if(BUILD_TESTING)
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add_subdirectory(test_common)

‎resource_detectors/BUILD‎

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# Copyright The OpenTelemetry Authors
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# SPDX-License-Identifier: Apache-2.0
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package(default_visibility = ["//visibility:public"])
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cc_library(
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name = "headers",
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hdrs = glob(["include/**/*.h"]),
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strip_include_prefix = "include",
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)
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cc_library(
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name = "resource_detectors",
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srcs = [
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"container_detector.cc",
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"container_detector_utils.cc",
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],
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deps = [
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"//api",
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"//resource_detectors:headers",
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"//sdk:headers",
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"//sdk/src/resource",
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],
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)

‎resource_detectors/CMakeLists.txt‎

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# Copyright The OpenTelemetry Authors
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# SPDX-License-Identifier: Apache-2.0
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add_library(opentelemetry_resource_detectors container_detector_utils.cc
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container_detector.cc)
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set_target_properties(opentelemetry_resource_detectors
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PROPERTIES EXPORT_NAME resource_detectors)
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set_target_version(opentelemetry_resource_detectors)
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target_link_libraries(opentelemetry_resource_detectors
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PUBLIC opentelemetry_resources)
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target_include_directories(
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opentelemetry_resource_detectors
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PUBLIC "$<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/include>"
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"$<INSTALL_INTERFACE:include>")
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otel_add_component(
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COMPONENT
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resource_detectors
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TARGETS
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opentelemetry_resource_detectors
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FILES_DIRECTORY
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"include/opentelemetry/"
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FILES_DESTINATION
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"include/opentelemetry"
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FILES_MATCHING
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PATTERN
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"*.h"
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PATTERN
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"container_detector_utils.h"
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EXCLUDE)
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if(BUILD_TESTING)
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add_subdirectory(test)
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endif()

‎resource_detectors/container_detector.cc‎

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// Copyright The OpenTelemetry Authors
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// SPDX-License-Identifier: Apache-2.0
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#include "opentelemetry/resource_detectors/container_detector.h"
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#include "opentelemetry/nostd/variant.h"
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#include "opentelemetry/resource_detectors/container_detector_utils.h"
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#include "opentelemetry/sdk/resource/resource.h"
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#include "opentelemetry/sdk/resource/resource_detector.h"
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#include "opentelemetry/semconv/incubating/container_attributes.h"
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#include "opentelemetry/version.h"
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#include <string>
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#include <unordered_map>
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#include <utility>
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OPENTELEMETRY_BEGIN_NAMESPACE
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namespace resource_detector
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{
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/**
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* This is the file path from where we can get container.id
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*/
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constexpr const char *kCGroupPath = "/proc/self/cgroup";
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opentelemetry::sdk::resource::Resource ContainerResourceDetector::Detect() noexcept
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{
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std::string container_id =
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opentelemetry::resource_detector::detail::GetContainerIDFromCgroup(kCGroupPath);
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if (container_id.empty())
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{
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return ResourceDetector::Create({});
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}
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opentelemetry::sdk::resource::ResourceAttributes attributes;
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attributes[semconv::container::kContainerId] = std::move(container_id);
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return ResourceDetector::Create(attributes);
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}
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} // namespace resource_detector
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OPENTELEMETRY_END_NAMESPACE

‎resource_detectors/container_detector_utils.cc‎

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// Copyright The OpenTelemetry Authors
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// SPDX-License-Identifier: Apache-2.0
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#include "opentelemetry/resource_detectors/container_detector_utils.h"
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#include "opentelemetry/nostd/string_view.h"
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#include <fstream>
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#include <regex>
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#include <string>
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#include "opentelemetry/version.h"
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OPENTELEMETRY_BEGIN_NAMESPACE
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namespace resource_detector
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{
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namespace detail
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{
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std::string GetContainerIDFromCgroup(const char *file_path)
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{
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std::ifstream cgroup_file(file_path);
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std::string line;
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while (std::getline(cgroup_file, line))
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{
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std::string container_id = ExtractContainerIDFromLine(line);
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if (!container_id.empty())
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{
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return container_id;
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}
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}
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return std::string();
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}
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std::string ExtractContainerIDFromLine(nostd::string_view line)
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{
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/**
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* This regex is designed to extract container IDs from cgroup file lines.
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* It matches hexadecimal container IDs used by container runtimes like Docker, containerd, and
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* cri-o.
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* Examples of matching lines:
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* - 0::/docker/3fae9b2c6d7e8f90123456789abcdef0123456789abcdef0123456789abcdef0
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* - "13:name=systemd:/podruntime/docker/kubepods/ac679f8a8319c8cf7d38e1adf263bc08d23.aaaa"
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* - "e857a4bf05a69080a759574949d7a0e69572e27647800fa7faff6a05a8332aa1"
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* Please see the test cases in resource_test.cc for more examples.
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*/
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static const std::regex container_id_regex(R"(^.*/(?:.*[-:])?([0-9a-f]+)(?:\.|\s*$))");
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std::match_results<const char *> match;
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if (std::regex_search(line.data(), line.data() + line.size(), match, container_id_regex))
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{
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return match.str(1);
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}
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return std::string();
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}
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} // namespace detail
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} // namespace resource_detector
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OPENTELEMETRY_END_NAMESPACE

‎resource_detectors/include/opentelemetry/resource_detectors/container_detector.h‎

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// Copyright The OpenTelemetry Authors
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// SPDX-License-Identifier: Apache-2.0
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#pragma once
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#include "opentelemetry/sdk/resource/resource.h"
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#include "opentelemetry/sdk/resource/resource_detector.h"
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#include "opentelemetry/version.h"
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OPENTELEMETRY_BEGIN_NAMESPACE
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namespace resource_detector
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{
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/**
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* ContainerResourceDetector to detect resource attributes when running inside a containerized
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* environment. This detector extracts metadata such as container ID from cgroup information and
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* sets attributes like container.id following the OpenTelemetry semantic conventions.
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*/
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class ContainerResourceDetector : public opentelemetry::sdk::resource::ResourceDetector
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{
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public:
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opentelemetry::sdk::resource::Resource Detect() noexcept override;
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};
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} // namespace resource_detector
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OPENTELEMETRY_END_NAMESPACE

‎resource_detectors/include/opentelemetry/resource_detectors/container_detector_utils.h‎

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// Copyright The OpenTelemetry Authors
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// SPDX-License-Identifier: Apache-2.0
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#pragma once
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#include <string>
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#include "opentelemetry/nostd/string_view.h"
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#include "opentelemetry/version.h"
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OPENTELEMETRY_BEGIN_NAMESPACE
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namespace resource_detector
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{
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namespace detail
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{
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/**
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* Reads the container.id from /proc/self/cgroup file.
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* @param file_path file path of cgroup
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* @return container.id as string or an empty string if not found on error
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*/
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std::string GetContainerIDFromCgroup(const char *file_path);
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/**
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* Matches the line with the regex to find container.id
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* @param line a single line of text, typically from the /proc/self/cgroup file
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* @return matched id or empty string
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*/
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std::string ExtractContainerIDFromLine(nostd::string_view line);
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} // namespace detail
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} // namespace resource_detector
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OPENTELEMETRY_END_NAMESPACE

‎resource_detectors/test/BUILD‎

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# Copyright The OpenTelemetry Authors
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# SPDX-License-Identifier: Apache-2.0
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cc_test(
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name = "resource_detector_test",
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srcs = [
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"container_detector_test.cc",
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],
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tags = ["test"],
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deps = [
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"//api",
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"//resource_detectors",
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"@com_google_googletest//:gtest_main",
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],
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)

‎resource_detectors/test/CMakeLists.txt‎

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# Copyright The OpenTelemetry Authors
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# SPDX-License-Identifier: Apache-2.0
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add_executable(resource_detector_test container_detector_test.cc)
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# Link the required dependencies
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target_link_libraries(
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resource_detector_test PRIVATE opentelemetry_resource_detectors
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opentelemetry_api GTest::gtest_main)
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gtest_add_tests(
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TARGET resource_detector_test
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TEST_PREFIX resource_detector.
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TEST_LIST resource_detector_test)

‎resource_detectors/test/container_detector_test.cc‎

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// Copyright The OpenTelemetry Authors
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// SPDX-License-Identifier: Apache-2.0
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#include <gtest/gtest.h>
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#include <cstdio>
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#include <fstream>
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#include <string>
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#include "opentelemetry/nostd/string_view.h"
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#include "opentelemetry/resource_detectors/container_detector_utils.h"
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TEST(ContainerIdDetectorTest, ExtractValidContainerIdFromLine)
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{
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std::string line =
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"13:name=systemd:/podruntime/docker/kubepods/ac679f8a8319c8cf7d38e1adf263bc08d23.aaaa";
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std::string extracted_id =
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opentelemetry::resource_detector::detail::ExtractContainerIDFromLine(line);
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EXPECT_EQ(std::string{"ac679f8a8319c8cf7d38e1adf263bc08d23"}, extracted_id);
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}
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TEST(ContainerIdDetectorTest, ExtractIdFromMockUpCGroupFile)
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{
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const char *filename = "test_cgroup.txt";
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{
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std::ofstream outfile(filename);
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outfile << "13:name=systemd:/kuberuntime/containerd"
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"/kubepods-pod872d2066_00ef_48ea_a7d8_51b18b72d739:cri-containerd:"
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"e857a4bf05a69080a759574949d7a0e69572e27647800fa7faff6a05a8332aa1\n";
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outfile << "9:cpu:/not-a-container\n";
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}
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std::string container_id =
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opentelemetry::resource_detector::detail::GetContainerIDFromCgroup(filename);
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EXPECT_EQ(container_id,
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std::string{"e857a4bf05a69080a759574949d7a0e69572e27647800fa7faff6a05a8332aa1"});
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std::remove(filename);
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}
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TEST(ContainerIdDetectorTest, DoesNotExtractInvalidLine)
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{
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std::string line = "this line does not contain a container id";
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std::string id = opentelemetry::resource_detector::detail::ExtractContainerIDFromLine(line);
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EXPECT_EQ(id, std::string{""});
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}
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TEST(ContainerIdDetectorTest, ReturnsEmptyOnNoMatch)
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{
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const char *filename = "test_empty_cgroup.txt";
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{
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std::ofstream outfile(filename);
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outfile << "no container id here\n";
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}
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std::string id = opentelemetry::resource_detector::detail::GetContainerIDFromCgroup(filename);
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EXPECT_EQ(id, std::string{""});
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std::remove(filename); // cleanup
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}
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TEST(ContainerIdDetectorTest, ReturnsEmptyOnFileFailingToOpen)
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{
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const char *filename = "test_invalid_cgroup.txt";
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std::string id = opentelemetry::resource_detector::detail::GetContainerIDFromCgroup(filename);
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EXPECT_EQ(id, std::string{""});
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}

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