add json logging

Cargo.nix

@@ -160,7 +160,10 @@ rec {
       sys_info."${deps.ofborg."0.1.9".sys_info}".default = true;
       tempfile."${deps.ofborg."0.1.9".tempfile}".default = true;
       tracing."${deps.ofborg."0.1.9".tracing}".default = true;
-      tracing_subscriber."${deps.ofborg."0.1.9".tracing_subscriber}".default = true;
+      tracing_subscriber = fold recursiveUpdate {} [
+        { "${deps.ofborg."0.1.9".tracing_subscriber}"."json" = true; }
+        { "${deps.ofborg."0.1.9".tracing_subscriber}".default = true; }
+      ];
       uuid = fold recursiveUpdate {} [
         { "${deps.ofborg."0.1.9".uuid}"."v4" = true; }
         { "${deps.ofborg."0.1.9".uuid}".default = true; }

ofborg/Cargo.toml

@@ -18,7 +18,7 @@ serde_derive = "1.0"
 serde_json = "1.0"
 tempfile = "2.2.0"
 tracing = "0.1.13"
-tracing-subscriber = "0.2.5"
+tracing-subscriber = { version = "0.2.5", features = ["json"] }
 hubcaps = { git = "https://github.com/grahamc/hubcaps.git" }
 #hubcaps = { path = "../../../grahamc/hubcaps/" } # for testing patches
 hyper = "0.10.*"

ofborg/src/lib.rs

@@ -11,6 +11,8 @@ extern crate serde_derive;
 #[macro_use]
 extern crate nom;
 
+use std::env;
+
 use tracing_subscriber::prelude::*;
 use tracing_subscriber::EnvFilter;
 
@@ -88,15 +90,25 @@ pub mod ofborg {
 }
 
 pub fn setup_log() {
-    let fmt_layer = tracing_subscriber::fmt::layer();
     let filter_layer = EnvFilter::try_from_default_env()
         .or_else(|_| EnvFilter::try_new("info"))
         .unwrap();
 
-    tracing_subscriber::registry()
-        .with(filter_layer)
-        .with(fmt_layer)
-        .init();
+    let log_json = env::var("RUST_LOG_JSON").map_or(false, |s| s == "1");
+
+    if log_json {
+        let fmt_layer = tracing_subscriber::fmt::layer().json().flatten_event(true);
+        tracing_subscriber::registry()
+            .with(filter_layer)
+            .with(fmt_layer)
+            .init();
+    } else {
+        let fmt_layer = tracing_subscriber::fmt::layer();
+        tracing_subscriber::registry()
+            .with(filter_layer)
+            .with(fmt_layer)
+            .init();
+    }
 
     tracing::info!("Logging configured");
 }