Invocation logging: add new field context variables

It allows to specify a list of environment variables, which are captured at
invocation time and stored as key-value pairs in the metadata file. This allows
to get some information about the invocation context such as username,
merge-request ID or source branch (on a CI runner), or others.

1 files changed, 9 insertions, 0 deletions

diff --git a/src/other_tools/just_mr/launch.cpp b/src/other_tools/just_mr/launch.cpp
index ca21e268..dc861c11 100644
--- a/src/other_tools/just_mr/launch.cpp
+++ b/src/other_tools/just_mr/launch.cpp
@@ -371,6 +371,15 @@ auto CallJust(std::optional<std::filesystem::path> const& config_file,
             meta["configuration"] = mr_config_pair->second;
         }
         meta["cmdline"] = cmd;
+        if (not invocation_log.context_vars.empty()) {
+            auto context = nlohmann::json::object();
+            for (auto const& env_var : invocation_log.context_vars) {
+                auto* env_value = std::getenv(env_var.c_str());
+                context[env_var] =
+                    env_value != nullptr ? env_value : nlohmann::json{};
+            }
+            meta["context"] = context;
+        }
         // "configuration" -- the blob-identifier of the multi-repo
         // configuration
         auto file_name = *log_dir / *invocation_log.metadata;