Patch-Source: https://github.com/meilisearch/meilisearch/pull/2812
--
From 97f3f12305becc94adc54883c8ac9a815f51b380 Mon Sep 17 00:00:00 2001
From: Jakub Jirutka <jakub@jirutka.cz>
Date: Wed, 28 Sep 2022 23:50:21 +0200
Subject: [PATCH] Add support for logging to syslog

If `MEILI_SYSLOG` is set or `--syslog` provided, the log messages will
be sent to the local syslog instead of the stderr. The log level can be
controlled using `MEILI_LOG_LEVEL` (or `--log-level`) as with logging
to the stderr, but the value must be a valid syslog level, otherwise
the program will panic.
---
 Cargo.lock                     | 40 ++++++++++++++++++++++++++++++++++
 meilisearch-http/Cargo.toml    |  1 +
 meilisearch-http/src/main.rs   | 24 ++++++++++++++------
 meilisearch-http/src/option.rs |  4 ++++
 4 files changed, 62 insertions(+), 7 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 7a0802e3e..4079aa5c9 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1096,6 +1096,15 @@ dependencies = [
  "termcolor",
 ]
 
+[[package]]
+name = "error-chain"
+version = "0.12.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2d2f06b9cac1506ece98fe3231e3cc9c4410ec3d5b1f24ae1c8946f0742cdefc"
+dependencies = [
+ "version_check",
+]
+
 [[package]]
 name = "fastrand"
 version = "1.7.0"
@@ -1487,6 +1496,17 @@ dependencies = [
  "digest",
 ]
 
+[[package]]
+name = "hostname"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3c731c3e10504cc8ed35cfe2f1db4c9274c3d35fa486e3b31df46f068ef3e867"
+dependencies = [
+ "libc",
+ "match_cfg",
+ "winapi",
+]
+
 [[package]]
 name = "http"
 version = "0.2.8"
@@ -1997,6 +2017,12 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3e2e65a1a2e43cfcb47a895c4c8b10d1f4a61097f9f254f183aee60cad9c651d"
 
+[[package]]
+name = "match_cfg"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ffbee8634e0d45d258acb448e7eaab3fce7a0a467395d4d9f228e3c1f01fb2e4"
+
 [[package]]
 name = "matches"
 version = "0.1.9"
@@ -2081,6 +2107,7 @@ dependencies = [
  "slice-group-by",
  "static-files",
  "sysinfo",
+ "syslog",
  "tar",
  "tempfile",
  "thiserror",
@@ -3382,6 +3409,19 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "syslog"
+version = "6.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "978044cc68150ad5e40083c9f6a725e6fd02d7ba1bcf691ec2ff0d66c0b41acc"
+dependencies = [
+ "error-chain",
+ "hostname",
+ "libc",
+ "log",
+ "time 0.3.14",
+]
+
 [[package]]
 name = "tar"
 version = "0.4.38"
diff --git a/meilisearch-http/Cargo.toml b/meilisearch-http/Cargo.toml
index baea8b578..f60b16fae 100644
--- a/meilisearch-http/Cargo.toml
+++ b/meilisearch-http/Cargo.toml
@@ -70,6 +70,7 @@ siphasher = "0.3.10"
 slice-group-by = "0.3.0"
 static-files = { version = "0.2.3", optional = true }
 sysinfo = "0.23.5"
+syslog = "6.0.1"
 tar = "0.4.38"
 tempfile = "3.3.0"
 thiserror = "1.0.30"
diff --git a/meilisearch-http/src/main.rs b/meilisearch-http/src/main.rs
index 9627aeef8..a13ccd6ce 100644
--- a/meilisearch-http/src/main.rs
+++ b/meilisearch-http/src/main.rs
@@ -15,14 +15,24 @@ static ALLOC: mimalloc::MiMalloc = mimalloc::MiMalloc;
 
 /// does all the setup before meilisearch is launched
 fn setup(opt: &Opt) -> anyhow::Result<()> {
-    let mut log_builder = env_logger::Builder::new();
-    log_builder.parse_filters(&opt.log_level);
-    if opt.log_level == "info" {
-        // if we are in info we only allow the warn log_level for milli
-        log_builder.filter_module("milli", log::LevelFilter::Warn);
-    }
+    if opt.syslog {
+        let level = opt.log_level.parse().expect(&format!(
+            "MEILI_LOG_LEVEL={} is not a valid syslog level",
+            opt.log_level
+        ));
+        syslog::init_unix(syslog::Facility::LOG_DAEMON, level)
+            .expect("Failed to connect to syslog");
+        eprintln!("Logging to syslog");
+    } else {
+        let mut log_builder = env_logger::Builder::new();
+        log_builder.parse_filters(&opt.log_level);
+        if opt.log_level == "info" {
+            // if we are in info we only allow the warn log_level for milli
+            log_builder.filter_module("milli", log::LevelFilter::Warn);
+        }
 
-    log_builder.init();
+        log_builder.init();
+    }
 
     Ok(())
 }
diff --git a/meilisearch-http/src/option.rs b/meilisearch-http/src/option.rs
index bdfa283a6..6484197cb 100644
--- a/meilisearch-http/src/option.rs
+++ b/meilisearch-http/src/option.rs
@@ -146,6 +146,10 @@ pub struct Opt {
     #[clap(long, env = "MEILI_LOG_LEVEL", default_value = "info")]
     pub log_level: String,
 
+    /// Send log messages to the local syslog instead of stderr.
+    #[clap(long, env = "MEILI_SYSLOG")]
+    pub syslog: bool,
+
     /// Enables Prometheus metrics and /metrics route.
     #[cfg(feature = "metrics")]
     #[clap(long, env = "MEILI_ENABLE_METRICS_ROUTE")]