From cf595b81d53a4fdeb30694a271bf1cfe1bd55c34 Mon Sep 17 00:00:00 2001
From: Tristan Ross <tristan.ross@determinate.systems>
Date: Tue, 23 Sep 2025 12:04:06 -0700
Subject: [PATCH 1/2] libmain-c: add nix_set_log_format function

---
 src/libmain-c/nix_api_main.cc | 13 +++++++++++++
 src/libmain-c/nix_api_main.h  |  8 ++++++++
 2 files changed, 21 insertions(+)

diff --git a/src/libmain-c/nix_api_main.cc b/src/libmain-c/nix_api_main.cc
index 2d4f588a8..0ee965dc8 100644
--- a/src/libmain-c/nix_api_main.cc
+++ b/src/libmain-c/nix_api_main.cc
@@ -4,6 +4,7 @@
 #include "nix_api_util_internal.h"
 
 #include "nix/main/plugin.hh"
+#include "nix/main/loggers.hh"
 
 extern "C" {
 
@@ -17,4 +18,16 @@ nix_err nix_init_plugins(nix_c_context * context)
     NIXC_CATCH_ERRS
 }
 
+nix_err nix_set_log_format(nix_c_context * context, const char * format)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    if (format == nullptr)
+        return nix_set_err_msg(context, NIX_ERR_UNKNOWN, "Log format is null");
+    try {
+        nix::setLogFormat(format);
+    }
+    NIXC_CATCH_ERRS
+}
+
 } // extern "C"
diff --git a/src/libmain-c/nix_api_main.h b/src/libmain-c/nix_api_main.h
index 3957b992f..3d5d12c15 100644
--- a/src/libmain-c/nix_api_main.h
+++ b/src/libmain-c/nix_api_main.h
@@ -30,6 +30,14 @@ extern "C" {
  */
 nix_err nix_init_plugins(nix_c_context * context);
 
+/**
+ * @brief Sets the log format
+ *
+ * @param[out] context Optional, stores error information
+ * @param[in] format The string name of the format.
+ */
+nix_err nix_set_log_format(nix_c_context * context, const char * format);
+
 // cffi end
 #ifdef __cplusplus
 }

From bb6a4dccdf2c828fda29ce34e55757b9a59b11f2 Mon Sep 17 00:00:00 2001
From: Tristan Ross <tristan.ross@determinate.systems>
Date: Tue, 23 Sep 2025 12:53:43 -0700
Subject: [PATCH 2/2] libutil-c: add nix_set_verbosity function

---
 src/libutil-c/nix_api_util.cc | 12 ++++++++++++
 src/libutil-c/nix_api_util.h  | 26 ++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/src/libutil-c/nix_api_util.cc b/src/libutil-c/nix_api_util.cc
index a43e7103b..3903823aa 100644
--- a/src/libutil-c/nix_api_util.cc
+++ b/src/libutil-c/nix_api_util.cc
@@ -159,4 +159,16 @@ nix_err call_nix_get_string_callback(const std::string str, nix_get_string_callb
     return NIX_OK;
 }
 
+nix_err nix_set_verbosity(nix_c_context * context, nix_verbosity level)
+{
+    if (context)
+        context->last_err_code = NIX_OK;
+    if (level > NIX_LVL_VOMIT || level < NIX_LVL_ERROR)
+        return nix_set_err_msg(context, NIX_ERR_UNKNOWN, "Invalid verbosity level");
+    try {
+        nix::verbosity = static_cast<nix::Verbosity>(level);
+    }
+    NIXC_CATCH_ERRS
+}
+
 } // extern "C"
diff --git a/src/libutil-c/nix_api_util.h b/src/libutil-c/nix_api_util.h
index 5f42641d4..608b463c0 100644
--- a/src/libutil-c/nix_api_util.h
+++ b/src/libutil-c/nix_api_util.h
@@ -102,6 +102,24 @@ enum nix_err {
 
 typedef enum nix_err nix_err;
 
+/**
+ * @brief Verbosity level
+ *
+ * @note This should be kept in sync with the C++ implementation (nix::Verbosity)
+ */
+enum nix_verbosity {
+    NIX_LVL_ERROR = 0,
+    NIX_LVL_WARN,
+    NIX_LVL_NOTICE,
+    NIX_LVL_INFO,
+    NIX_LVL_TALKATIVE,
+    NIX_LVL_CHATTY,
+    NIX_LVL_DEBUG,
+    NIX_LVL_VOMIT,
+};
+
+typedef enum nix_verbosity nix_verbosity;
+
 /**
  * @brief This object stores error state.
  * @struct nix_c_context
@@ -316,6 +334,14 @@ nix_err nix_set_err_msg(nix_c_context * context, nix_err err, const char * msg);
  */
 void nix_clear_err(nix_c_context * context);
 
+/**
+ * @brief Sets the verbosity level
+ *
+ * @param[out] context Optional, additional error context.
+ * @param[in] level Verbosity level
+ */
+nix_err nix_set_verbosity(nix_c_context * context, nix_verbosity level);
+
 /**
  *  @}
  */