Update sccache-dist to use SCCACHE_LOG. (mozilla#977)

* Update sccache-dist to use SCCACHE_LOG.

This fixes mozilla#969 which was overlooked when fixing mozilla#810.

* Update sccache-dist docs and tests.

This replaces usage of `RUST_LOG` with `SCCACHE_LOG` in the docs and
the tests.

* Fix up missed conflict markers...

docs/DistributedQuickstart.md

@@ -57,7 +57,7 @@ Start the scheduler by running:
 sccache-dist scheduler --config scheduler.conf
 ```
 
-Like the local server, the scheduler process will daemonize itself unless `SCCACHE_NO_DAEMON=1` is set. If the scheduler fails to start you may need to set `RUST_LOG=trace` when starting it to get useful diagnostics.
+Like the local server, the scheduler process will daemonize itself unless `SCCACHE_NO_DAEMON=1` is set. If the scheduler fails to start you may need to set `SCCACHE_LOG=trace` when starting it to get useful diagnostics.
 
 Configure a build server
 ------------------------
@@ -98,7 +98,7 @@ Due to bubblewrap requirements currently the build server *must* be run as root.
 sudo sccache-dist server --config server.conf
 ```
 
-As with the scheduler, if the build server fails to start you may need to set `RUST_LOG=trace` to get useful diagnostics.
+As with the scheduler, if the build server fails to start you may need to set `SCCACHE_LOG=trace` to get useful diagnostics.
 
 Configure a client
 ------------------

src/bin/sccache-dist/main.rs

@@ -436,8 +436,8 @@ fn run(command: Command) -> Result<i32> {
 }
 
 fn init_logging() {
-    if env::var("RUST_LOG").is_ok() {
-        match env_logger::try_init() {
+    if env::var(sccache::LOGGING_ENV).is_ok() {
+        match env_logger::Builder::from_env(sccache::LOGGING_ENV).try_init() {
             Ok(_) => (),
             Err(e) => panic!("Failed to initalize logging: {:?}", e),
         }

src/lib.rs

@@ -63,7 +63,9 @@ pub mod util;
 
 use std::env;
 
-const LOGGING_ENV: &str = "SCCACHE_LOG";
+/// Used to denote the environment variable that controls
+/// logging for sccache, and sccache-dist.
+pub const LOGGING_ENV: &str = "SCCACHE_LOG";
 
 pub fn main() {
     init_logging();

tests/dist.rs

@@ -25,7 +25,7 @@ mod harness;
 fn basic_compile(tmpdir: &Path, sccache_cfg_path: &Path, sccache_cached_cfg_path: &Path) {
     let envs: Vec<(_, &OsStr)> = vec![
         ("RUST_BACKTRACE", "1".as_ref()),
-        ("RUST_LOG", "sccache=trace".as_ref()),
+        ("SCCACHE_LOG", "sccache=trace".as_ref()),
         ("SCCACHE_CONF", sccache_cfg_path.as_ref()),
         ("SCCACHE_CACHED_CONF", sccache_cached_cfg_path.as_ref()),
     ];

tests/harness/mod.rs

@@ -266,7 +266,7 @@ impl DistSystem {
                 "-e",
                 "SCCACHE_NO_DAEMON=1",
                 "-e",
-                "RUST_LOG=sccache=trace",
+                "SCCACHE_LOG=sccache=trace",
                 "-e",
                 "RUST_BACKTRACE=1",
                 "-v",
@@ -332,7 +332,7 @@ impl DistSystem {
                 "--name",
                 &server_name,
                 "-e",
-                "RUST_LOG=sccache=trace",
+                "SCCACHE_LOG=sccache=trace",
                 "-e",
                 "RUST_BACKTRACE=1",
                 "-v",
@@ -400,7 +400,7 @@ impl DistSystem {
                 child
             }
             ForkResult::Child => {
-                env::set_var("RUST_LOG", "sccache=trace");
+                env::set_var("SCCACHE_LOG", "sccache=trace");
                 env_logger::try_init().unwrap();
                 void::unreachable(server.start().unwrap())
             }

tests/oauth.rs

@@ -231,7 +231,7 @@ fn test_auth_with_config(dist_auth: sccache::config::DistAuth) {
         .unwrap();
     let sccache_cached_config_path = conf_dir.path().join("sccache-cached-config");
     let envs = vec![
-        ("RUST_LOG", "sccache=trace".into()),
+        ("SCCACHE_LOG", "sccache=trace".into()),
         ("SCCACHE_CONF", sccache_config_path.into_os_string()),
         (
             "SCCACHE_CACHED_CONF",