Rename container::find_docker_container_id to container::find_container_id and update its implementation so that it is regex-based and covers the same set of inputs as other tracers, like Java and .NET -- the implementation is borrowed from the Java tracer

Author: zacharycmontoya

src/datadog/platform_util.cpp

@@ -2,6 +2,8 @@
 
 #include <cstdint>
 #include <fstream>
+#include <cassert>
+#include <regex>
 
 // clang-format off
 #if defined(__x86_64__) || defined(_M_X64)
@@ -338,31 +340,33 @@ Optional<Cgroup> get_cgroup_version() {
   return nullopt;
 }
 
-Optional<std::string> find_docker_container_id_from_cgroup() {
+Optional<std::string> find_container_id_from_cgroup() {
   auto cgroup_fd = std::ifstream("/proc/self/cgroup", std::ios::in);
   if (!cgroup_fd.is_open()) return nullopt;
 
-  return find_docker_container_id(cgroup_fd);
+  return find_container_id(cgroup_fd);
 }
 #endif
 }  // namespace
 
-Optional<std::string> find_docker_container_id(std::istream& source) {
-  constexpr std::string_view docker_str = "docker-";
+Optional<std::string> find_container_id(std::istream& source) {
+  static const std::string uuid_regex_str = "[0-9a-f]{8}[-_][0-9a-f]{4}[-_][0-9a-f]{4}[-_][0-9a-f]{4}[-_][0-9a-f]{12}|(?:[0-9a-f]{8}(?:-[0-9a-f]{4}){4}$)";
+  static const std::string container_regex_str = "[0-9a-f]{64}";
+  static const std::string task_regex_str = "[0-9a-f]{32}-\\d+";
+  static const std::regex path_reg(
+      "(?:.+)?(" + uuid_regex_str + "|" + container_regex_str + "|" + task_regex_str +
+      ")(?:\\.scope)?$");
 
   std::string line;
   while (std::getline(source, line)) {
     // Example:
     // `0::/system.slice/docker-abcdef0123456789abcdef0123456789.scope`
-    if (auto beg = line.find(docker_str); beg != std::string::npos) {
-      beg += docker_str.size();
-      auto end = line.find(".scope", beg);
-      if (end == std::string::npos || end - beg <= 0) {
-        continue;
-      }
+    std::smatch match;
+    if (std::regex_match(line, match, path_reg)) {
+      assert(match.ready());
+      assert(match.size() == 2);
 
-      auto container_id = line.substr(beg, end - beg);
-      return container_id;
+      return match.str(1);
     }
   }
 
@@ -382,7 +386,7 @@ Optional<ContainerID> get_id() {
   ContainerID id;
   switch (*maybe_cgroup) {
     case Cgroup::v1: {
-      if (auto maybe_id = find_docker_container_id_from_cgroup()) {
+      if (auto maybe_id = find_container_id_from_cgroup()) {
         id.value = *maybe_id;
         id.type = ContainerID::Type::container_id;
         break;

src/datadog/platform_util.h

@@ -84,13 +84,13 @@ struct ContainerID final {
   std::string value;
 };
 
-/// Find the docker container ID from a given source.
+/// Find the container ID from a given source.
 /// This function is exposed mainly for testing purposes.
 ///
-/// @param source The input from which to read the Docker container ID.
-/// @return An Optional containing the Docker container ID if found, otherwise
+/// @param source The input from which to read the container ID.
+/// @return An Optional containing the container ID if found, otherwise
 /// nothing.
-Optional<std::string> find_docker_container_id(std::istream& source);
+Optional<std::string> find_container_id(std::istream& source);
 
 /// Function to retrieve the container metadata.
 ///

test/test_platform_util.cpp

@@ -56,7 +56,50 @@ PLATFORM_UTIL_TEST("find docker container ID") {
 
   std::istringstream is(test_case.input);
 
-  auto maybe_container_id = container::find_docker_container_id(is);
+  auto maybe_container_id = container::find_container_id(is);
+  if (test_case.expected_container_id.has_value()) {
+    REQUIRE(maybe_container_id.has_value());
+    CHECK(*maybe_container_id == *test_case.expected_container_id);
+  } else {
+    CHECK(!maybe_container_id.has_value());
+  }
+}
+
+PLATFORM_UTIL_TEST("find Fargate 1.3 container ID") {
+  struct TestCase {
+    size_t line;
+    std::string_view name;
+    std::string input;
+    Optional<std::string> expected_container_id;
+  };
+
+  auto test_case = GENERATE(values<TestCase>({
+      {__LINE__, "empty inputs", "", nullopt},
+      {__LINE__, "no Fargate 1.3 container ID", "coucou", nullopt},
+      {__LINE__, "one line with Fargate 1.3 container ID",
+       "1:name=systemd:/ecs/55091c13-b8cf-4801-b527-f4601742204d/432624d2150b349fe35ba397284dea788c2bf66b885d14dfc1569b01890ca7da",
+       "432624d2150b349fe35ba397284dea788c2bf66b885d14dfc1569b01890ca7da"},
+      {__LINE__, "multiline with Fargate 1.3 container ID", R"(
+11:hugetlb:/ecs/55091c13-b8cf-4801-b527-f4601742204d/432624d2150b349fe35ba397284dea788c2bf66b885d14dfc1569b01890ca7da
+10:pids:/ecs/55091c13-b8cf-4801-b527-f4601742204d/432624d2150b349fe35ba397284dea788c2bf66b885d14dfc1569b01890ca7da
+9:cpuset:/ecs/55091c13-b8cf-4801-b527-f4601742204d/432624d2150b349fe35ba397284dea788c2bf66b885d14dfc1569b01890ca7da
+8:net_cls,net_prio:/ecs/55091c13-b8cf-4801-b527-f4601742204d/432624d2150b349fe35ba397284dea788c2bf66b885d14dfc1569b01890ca7da
+7:cpu,cpuacct:/ecs/55091c13-b8cf-4801-b527-f4601742204d/432624d2150b349fe35ba397284dea788c2bf66b885d14dfc1569b01890ca7da
+6:perf_event:/ecs/55091c13-b8cf-4801-b527-f4601742204d/432624d2150b349fe35ba397284dea788c2bf66b885d14dfc1569b01890ca7da
+5:freezer:/ecs/55091c13-b8cf-4801-b527-f4601742204d/432624d2150b349fe35ba397284dea788c2bf66b885d14dfc1569b01890ca7da
+4:devices:/ecs/55091c13-b8cf-4801-b527-f4601742204d/432624d2150b349fe35ba397284dea788c2bf66b885d14dfc1569b01890ca7da
+3:blkio:/ecs/55091c13-b8cf-4801-b527-f4601742204d/432624d2150b349fe35ba397284dea788c2bf66b885d14dfc1569b01890ca7da
+2:memory:/ecs/55091c13-b8cf-4801-b527-f4601742204d/432624d2150b349fe35ba397284dea788c2bf66b885d14dfc1569b01890ca7da
+1:name=systemd:/ecs/55091c13-b8cf-4801-b527-f4601742204d/432624d2150b349fe35ba397284dea788c2bf66b885d14dfc1569b01890ca7da
+    )",
+       "432624d2150b349fe35ba397284dea788c2bf66b885d14dfc1569b01890ca7da"},
+  }));
+
+  CAPTURE(test_case.name);
+
+  std::istringstream is(test_case.input);
+
+  auto maybe_container_id = container::find_container_id(is);
   if (test_case.expected_container_id.has_value()) {
     REQUIRE(maybe_container_id.has_value());
     CHECK(*maybe_container_id == *test_case.expected_container_id);