3 files changed, 55 insertions, 0 deletions
diff --git a/third_party/rust/jsparagus-json-log/.cargo-checksum.json b/third_party/rust/jsparagus-json-log/.cargo-checksum.json
new file mode 100644
index 0000000000..68d2763206
--- /dev/null
+++ b/third_party/rust/jsparagus-json-log/.cargo-checksum.json
@@ -0,0 +1 @@
+{"files":{"Cargo.toml":"9f2d19883ad7a40debdac46726fd7709e53aba7b8a23d7843d085df44c0d6f2f","src/lib.rs":"09352799b74833de10a95ce1097fb0d1a3f3474468f61dc9adeb58705508e632"},"package":null}
+\ No newline at end of file
diff --git a/third_party/rust/jsparagus-json-log/Cargo.toml b/third_party/rust/jsparagus-json-log/Cargo.toml
new file mode 100644
index 0000000000..151bd9d17c
--- /dev/null
+++ b/third_party/rust/jsparagus-json-log/Cargo.toml
@@ -0,0 +1,13 @@
+[package]
+name = "jsparagus-json-log"
+version = "0.1.0"
+authors = ["The jsparagus Project Developers"]
+edition = "2018"
+license = "MIT/Apache-2.0"
+
+[dependencies]
+log = { version = "0.4.0", features = ["max_level_debug", "release_max_level_warn"], optional = true }
+serde_json = { version = "1.0", optional = true }
+
+[features]
+logging = ["log", "serde_json"]
diff --git a/third_party/rust/jsparagus-json-log/src/lib.rs b/third_party/rust/jsparagus-json-log/src/lib.rs
new file mode 100644
index 0000000000..ed818566e5
--- /dev/null
+++ b/third_party/rust/jsparagus-json-log/src/lib.rs
@@ -0,0 +1,41 @@
+//! Provides a debug/trace output with json format.
+//! This is disabled by default, and can be enabled by "logging" feature.
+
+#[cfg(feature = "logging")]
+pub use log::{debug, trace};
+#[cfg(feature = "logging")]
+pub use serde_json::json;
+
+#[cfg(not(feature = "logging"))]
+#[macro_export]
+macro_rules! json_debug {
+    ($($t:tt)*) => {};
+}
+
+#[cfg(feature = "logging")]
+#[macro_export(local_inner_macros)]
+macro_rules! json_debug {
+    ($($t:tt)*) => {
+        debug!(
+            "{}",
+            json!($($t)*)
+        );
+    };
+}
+
+#[cfg(not(feature = "logging"))]
+#[macro_export]
+macro_rules! json_trace {
+    ($($t:tt)*) => {};
+}
+
+#[cfg(feature = "logging")]
+#[macro_export(local_inner_macros)]
+macro_rules! json_trace {
+    ($($t:tt)*) => {
+        trace!(
+            "{}",
+            json!($($t)*)
+        );
+    };
+}