8000 [SDK] Implementation of container resource as per semconv · open-telemetry/opentelemetry-cpp@c740ddb · GitHub
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nikhilbhatia08nikhilbhatia08
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[SDK] Implementation of container resource as per semconv
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8 files changed

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‎sdk/include/opentelemetry/sdk/common/container.h‎

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@@ -0,0 +1,30 @@
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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/version.h"
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OPENTELEMETRY_BEGIN_NAMESPACE
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namespace sdk
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{
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namespace common
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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 empty string
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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 contains
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@return matched id or empty string
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*/
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std::string ExtractContainerIDFromLine(std::string &line);
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} // namespace common
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} // namespace sdk
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OPENTELEMETRY_END_NAMESPACE

‎sdk/include/opentelemetry/sdk/resource/resource_detector.h‎

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@@ -39,6 +39,17 @@ class OTELResourceDetector : public ResourceDetector
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Resource Detect() noexcept override;
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};
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/**
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* ContainerResourceDetector to detect resource attributes when running inside a containerized environment.
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* This detector extracts metadata such as container ID from cgroup information
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* and sets attributes like container.id following the OpenTelemetry semantic conventions.
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*/
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class ContainerResourceDetector : public ResourceDetector
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{
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public:
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Resource Detect() noexcept override;
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};
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} // namespace resource
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} // namespace sdk
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OPENTELEMETRY_END_NAMESPACE

‎sdk/src/common/BUILD‎

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@@ -57,6 +57,17 @@ cc_library(
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],
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)
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cc_library(
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name = "container",
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srcs = [
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"container.cc",
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],
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deps = [
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"//api",
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"//sdk:headers",
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],
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)
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cc_library(
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name = "global_log_handler",
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srcs = [

‎sdk/src/common/CMakeLists.txt‎

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@@ -1,7 +1,7 @@
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# Copyright The OpenTelemetry Authors
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# SPDX-License-Identifier: Apache-2.0
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4-
set(COMMON_SRCS random.cc global_log_handler.cc env_variables.cc base64.cc
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set(COMMON_SRCS random.cc global_log_handler.cc env_variables.cc container.cc base64.cc
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disabled.cc)
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if(WIN32)
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list(APPEND COMMON_SRCS platform/fork_windows.cc)

‎sdk/src/common/container.cc‎

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@@ -0,0 +1,53 @@
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// Copyright The OpenTelemetry Authors
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// SPDX-License-Identifier: Apache-2.0
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#include "opentelemetry/sdk/common/container.h"
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#ifdef _MSC_VER
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# include <string.h>
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# define strcasecmp _stricmp
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#else
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# include <strings.h>
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#endif
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#include <fstream>
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#include <regex>
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#include "opentelemetry/version.h"
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OPENTELEMETRY_BEGIN_NAMESPACE
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namespace sdk
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{
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namespace common
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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 "";
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}
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std::string ExtractContainerIDFromLine(std::string &line)
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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::smatch match;
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if (std::regex_search(line, 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 "";
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}
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} // namespace common
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} // namespace sdk
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OPENTELEMETRY_END_NAMESPACE

‎sdk/src/resource/resource.cc‎

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -41,8 +41,9 @@ Resource Resource::Merge(const Resource &other) const noexcept
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Resource Resource::Create(const ResourceAttributes &attributes, const std::string &schema_url)
4242
{
4343
static auto otel_resource = OTELResourceDetector().Detect();
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static auto container_resource = ContainerResourceDetector().Detect();
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auto resource =
45-
Resource::GetDefault().Merge(otel_resource).Merge(Resource{attributes, schema_url});
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Resource::GetDefault().Merge(otel_resource).Merge(container_resource).Merge(Resource{attributes, schema_url});
4647

4748
if (resource.attributes_.find(semconv::service::kServiceName) == resource.attributes_.end())
4849
{

‎sdk/src/resource/resource_detector.cc‎

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@@ -4,8 +4,10 @@
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#include "opentelemetry/sdk/resource/resource_detector.h"
55
#include "opentelemetry/nostd/variant.h"
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#include "opentelemetry/sdk/common/env_variables.h"
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#include "opentelemetry/sdk/common/container.h"
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#include "opentelemetry/sdk/resource/resource.h"
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#include "opentelemetry/semconv/service_attributes.h"
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#include "opentelemetry/semconv/incubating/container_attributes.h"
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#include "opentelemetry/version.h"
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1113
#include <stddef.h>
@@ -21,6 +23,10 @@ namespace resource
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2224
const char *OTEL_RESOURCE_ATTRIBUTES = "OTEL_RESOURCE_ATTRIBUTES";
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const char *OTEL_SERVICE_NAME = "OTEL_SERVICE_NAME";
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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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const char *C_GROUP_PATH = "/proc/self/cgroup";
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2531
Resource ResourceDetector::Create(const ResourceAttributes &attributes,
2632
const std::string &schema_url)
@@ -68,6 +74,23 @@ Resource OTELResourceDetector::Detect() noexcept
6874
return ResourceDetector::Create(attributes);
6975
}
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77+
Resource ContainerResourceDetector::Detect() noexcept
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{
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std::string container_id = opentelemetry::sdk::common::GetContainerIDFromCgroup(C_GROUP_PATH);
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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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ResourceAttributes attributes;
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if(!container_id.empty())
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{
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attributes[semconv::container::kContainerId] = container_id;
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}
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return ResourceDetector::Create(attributes);
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}
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} // namespace resource
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} // namespace sdk
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OPENTELEMETRY_END_NAMESPACE

‎sdk/test/resource/resource_test.cc‎

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@@ -8,9 +8,11 @@
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#include <string>
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#include <unordered_map>
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#include <utility>
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#include<fstream>
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#include "opentelemetry/nostd/variant.h"
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#include "opentelemetry/sdk/common/attribute_utils.h"
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#include "opentelemetry/sdk/common/container.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/sdk/version/version.h"
@@ -292,3 +294,48 @@ TEST(ResourceTest, DerivedResourceDetector)
292294
EXPECT_EQ(resource.GetSchemaURL(), detector.schema_url);
293295
EXPECT_TRUE(received_attributes.find("key") != received_attributes.end());
294296
}
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TEST(ResourceTest, ExctractValidContainerId)
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{
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std::string line = "13:name=systemd:/podruntime/docker/kubepods/ac679f8a8319c8cf7d38e1adf263bc08d23.aaaa";
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std::string extracted_id = opentelemetry::sdk::common::ExtractContainerIDFromLine(line);
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EXPECT_EQ(std::string{"ac679f8a8319c8cf7d38e1adf263bc08d23"}, extracted_id);
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}
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TEST(ResourceTest, 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/kubepods-pod872d2066_00ef_48ea_a7d8_51b18b72d739:cri-containerd: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 = opentelemetry::sdk::common::GetContainerIDFromCgroup(filename);
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EXPECT_EQ(container_id, std::string{"e857a4bf05a69080a759574949d7a0e69572e27647800fa7faff6a05a8332aa1"});
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std::remove(filename);
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}
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TEST(ResourceTest, DoesNotExtractInvalidLine)
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{
323+
std::string line = "this line does not contain a container id";
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std::string id = opentelemetry::sdk::common::ExtractContainerIDFromLine(line);
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EXPECT_EQ(id, std::string{""});
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}
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TEST(ContainerIdDetectorTest, ReturnsEmptyOnNoMatch)
329+
{
330+
const char *filename = "test_empty_cgroup.txt";
331+
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{
333+
std::ofstream outfile(filename);
334+
outfile << "no container id here\n";
335+
}
336+
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std::string id = opentelemetry::sdk::common::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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