From fa8764984f869a755e3046dddcb51751a8260321 Mon Sep 17 00:00:00 2001
From: Lucas Schwiderski <lucas@lschwiderski.de>
Date: Wed, 1 Mar 2023 20:12:18 +0100
Subject: [PATCH] feat(dtmm): Rework log levels and filters

Keep the flexibility for dev, but in prod drop stdout and restrict the
log view to stuff useful to the user.
---
 crates/dtmm/src/util/log.rs | 43 ++++++++++++-------------------------
 lib/dtmt-shared/src/log.rs  |  8 +++----
 2 files changed, 18 insertions(+), 33 deletions(-)

diff --git a/crates/dtmm/src/util/log.rs b/crates/dtmm/src/util/log.rs
index 12aeeff..e6a019e 100644
--- a/crates/dtmm/src/util/log.rs
+++ b/crates/dtmm/src/util/log.rs
@@ -7,10 +7,6 @@ use tracing_subscriber::layer::SubscriberExt;
 use tracing_subscriber::prelude::*;
 use tracing_subscriber::EnvFilter;
 
-// I currently cannot find a way to add a parameter to `dtmt_shared::create_tracing_subscriber`
-// that would allow me to pass an extra `Layer` to that function. So, for now,
-// its code has to be duplicated here.
-
 pub struct ChannelWriter {
     tx: UnboundedSender<String>,
 }
@@ -39,42 +35,31 @@ impl std::io::Write for ChannelWriter {
 }
 
 pub fn create_tracing_subscriber(tx: UnboundedSender<String>) {
-    let env_layer =
-        EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::try_new("info").unwrap());
-
-    let (dev_stdout_layer, prod_stdout_layer, filter_layer) = if cfg!(debug_assertions) {
-        let fmt_layer = fmt::layer().pretty();
-        (Some(fmt_layer), None, None)
+    let env_layer = if cfg!(debug_assertions) {
+        EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::new("info"))
     } else {
-        // Creates a layer that
-        // - only prints events that contain a message
-        // - does not print fields
-        // - does not print spans/targets
-        // - only prints time, not date
-        let fmt_layer = fmt::layer()
-            .event_format(dtmt_shared::Formatter)
-            .fmt_fields(debug_fn(dtmt_shared::format_field));
+        EnvFilter::new("error,dtmm=info")
+    };
 
-        (
-            None,
-            Some(fmt_layer),
-            Some(FilterFn::new(dtmt_shared::filter)),
-        )
+    let stdout_layer = if cfg!(debug_assertions) {
+        let layer = fmt::layer().pretty();
+        Some(layer)
+    } else {
+        None
     };
 
     let channel_layer = fmt::layer()
         // TODO: Re-enable and implement a formatter for the Druid widget
         .with_ansi(false)
         .event_format(dtmt_shared::Formatter)
-        .fmt_fields(debug_fn(dtmt_shared::format_field))
-        .with_writer(move || ChannelWriter::new(tx.clone()));
+        .fmt_fields(debug_fn(dtmt_shared::format_fields))
+        .with_writer(move || ChannelWriter::new(tx.clone()))
+        .with_filter(FilterFn::new(dtmt_shared::filter_fields));
 
     tracing_subscriber::registry()
-        .with(channel_layer)
-        .with(filter_layer)
         .with(env_layer)
-        .with(dev_stdout_layer)
-        .with(prod_stdout_layer)
+        .with(channel_layer)
+        .with(stdout_layer)
         .with(ErrorLayer::new(fmt::format::Pretty::default()))
         .init();
 }
diff --git a/lib/dtmt-shared/src/log.rs b/lib/dtmt-shared/src/log.rs
index 15a26b1..3c46a4b 100644
--- a/lib/dtmt-shared/src/log.rs
+++ b/lib/dtmt-shared/src/log.rs
@@ -16,7 +16,7 @@ use tracing_subscriber::EnvFilter;
 
 pub const TIME_FORMAT: &[FormatItem] = format_description!("[hour]:[minute]:[second]");
 
-pub fn format_field(w: &mut Writer<'_>, field: &Field, val: &dyn std::fmt::Debug) -> Result {
+pub fn format_fields(w: &mut Writer<'_>, field: &Field, val: &dyn std::fmt::Debug) -> Result {
     if field.name() == "message" {
         write!(w, "{:?}", val)
     } else {
@@ -24,7 +24,7 @@ pub fn format_field(w: &mut Writer<'_>, field: &Field, val: &dyn std::fmt::Debug
     }
 }
 
-pub fn filter(metadata: &Metadata<'_>) -> bool {
+pub fn filter_fields(metadata: &Metadata<'_>) -> bool {
     metadata
         .fields()
         .iter()
@@ -72,9 +72,9 @@ pub fn create_tracing_subscriber() {
         // - only prints time, not date
         let fmt_layer = fmt::layer()
             .event_format(Formatter)
-            .fmt_fields(debug_fn(format_field));
+            .fmt_fields(debug_fn(format_fields));
 
-        (None, Some(fmt_layer), Some(FilterFn::new(filter)))
+        (None, Some(fmt_layer), Some(FilterFn::new(filter_fields)))
     };
 
     tracing_subscriber::registry()