linkd: Add logging

Signed-off-by: Alexander Simmerl <[email protected]>

linkd/Cargo.toml

@@ -19,8 +19,10 @@ test    = false
 [dependencies]
 anyhow              = "1.0"
 base64              = "0.13"
+env_logger          = "0.9"
 futures             = "0.3"
 lazy_static         = "1.4"
+log                 = "0.4"
 nix                 = "0.22"
 signal-hook         = { version = "0.3", default-features = false }
 signal-hook-tokio   = { version = "0.3", features = [ "futures-v0_3" ] }

linkd/src/bin/linkd.rs

@@ -11,18 +11,17 @@ use signal_hook_tokio::Signals;
 use structopt::StructOpt as _;
 use tokio::{net::UnixStream, spawn, sync::mpsc};
 use tracing::info;
-use tracing_subscriber::FmtSubscriber;
 
 use librad::{
     crypto::BoxedSigner,
     net::{discovery, peer::Peer},
 };
 
-use linkd::{args::Args, cfg::Cfg, protocol, signals, socket_activation};
+use linkd::{args::Args, cfg::Cfg, logging, protocol, signals, socket_activation};
 
 #[tokio::main]
 async fn main() -> anyhow::Result<()> {
-    tracing::subscriber::set_global_default(FmtSubscriber::builder().finish())?;
+    logging::init();
 
     let args = Args::from_args();
     let cfg: Cfg<BoxedSigner> = Cfg::from_args::<UnixStream>(args).await?;

linkd/src/lib.rs

@@ -5,6 +5,7 @@
 
 pub mod args;
 pub mod cfg;
+pub mod logging;
 pub mod protocol;
 pub mod signals;
 pub mod socket_activation;

linkd/src/logging.rs

@@ -0,0 +1,51 @@
+// Copyright © 2021 The Radicle Link Contributors
+//
+// This file is part of radicle-link, distributed under the GPLv3 with Radicle
+// Linking Exception. For full terms see the included LICENSE file.
+
+use std::env;
+
+use log::{log_enabled, Level};
+use tracing::subscriber::set_global_default as set_subscriber;
+use tracing_subscriber::{EnvFilter, FmtSubscriber};
+
+/// Initialise logging / tracing
+///
+/// The `TRACING_FMT` environment variable can be used to control the log
+/// formatting. Supported values:
+///
+/// * "pretty": [`tracing_subscriber::fmt::format::Pretty`]
+/// * "compact": [`tracing_subscriber::fmt::format::Compact`]
+/// * "json": [`tracing_subscriber::fmt::format::Json`]
+///
+/// If the variable is not set, or set to any other value, the
+/// [`tracing_subscriber::fmt::format::Full`] format is used.
+pub fn init() {
+    if env_logger::builder().try_init().is_ok() {
+        if env::var("RUST_LOG").is_err() {
+            env::set_var("RUST_LOG", "debug");
+        }
+
+        let mut builder = FmtSubscriber::builder()
+            .with_env_filter(EnvFilter::from_default_env())
+            .with_test_writer();
+        if log_enabled!(target: "librad", Level::Trace) {
+            builder = builder.with_thread_ids(true);
+        } else if env::var("TRACING_FMT").is_err() {
+            let default_format = if env::var("CI").is_ok() {
+                "compact"
+            } else {
+                "pretty"
+            };
+            env::set_var("TRACING_FMT", default_format);
+        }
+
+        match env::var("TRACING_FMT").ok().as_deref() {
+            Some("pretty") => set_subscriber(builder.pretty().finish()),
+            Some("compact") => set_subscriber(builder.compact().finish()),
+            Some("json") => set_subscriber(builder.json().flatten_event(true).finish()),
+            _ => set_subscriber(builder.finish()),
+        }
+        .expect("setting tracing subscriber failed")
+    }
+}