WIP: Add file based log driver

conmon-rs/server/Cargo.toml

@@ -28,6 +28,7 @@ strum = { version = "0.24.1", features = ["derive"] }
 shadow-rs = "=0.16.1"
 multimap = "0.8.3"
 tracing = "0.1.36"
+tracing-appender = "0.2.2"
 tracing-journald = "0.3.0"
 tracing-subscriber = "0.3.15"
 uuid = { version = "1.1.2", features = ["v4", "fast-rng", "macro-diagnostics"] }

conmon-rs/server/src/config.rs

@@ -48,17 +48,18 @@ pub struct Config {
     /// The logging level of the conmon server.
     log_level: String,
 
-    #[get_copy = "pub"]
+    #[get = "pub"]
     #[clap(
         default_value(LogDriver::Systemd.into()),
-        env(concat!(prefix!(), "LOG_DRIVER")),
-        long("log-driver"),
+        env(concat!(prefix!(), "LOG_DRIVERS")),
+        multiple(true),
+        long("log-drivers"),
         short('d'),
         possible_values(LogDriver::iter().map(|x| x.into()).collect::<Vec<&str>>()),
-        value_name("DRIVER")
+        value_name("DRIVERS")
     )]
-    /// The logging driver used by the conmon server.
-    log_driver: LogDriver,
+    /// The logging drivers used by the server. Can be specified multiple times.
+    log_drivers: Vec<LogDriver>,
 
     #[get = "pub"]
     #[clap(
@@ -128,11 +129,15 @@ pub struct Config {
 #[strum(serialize_all = "lowercase")]
 /// Available log drivers.
 pub enum LogDriver {
-    /// Log to stdout
+    /// Log to stdout.
     Stdout,
 
-    /// Use systemd journald as log driver
+    /// Use systemd journald as log driver.
     Systemd,
+
+    /// Use a file destination as log driver. The log file path fill be generated to match
+    /// `[--runtime-dir]/logs/conmonrs.YYYY-MM-DD` and rotates on a daily basis.
+    File,
 }
 
 #[derive(

conmon-rs/server/src/server.rs

@@ -11,6 +11,7 @@ use crate::{
 use anyhow::{format_err, Context, Result};
 use capnp::text_list::Reader;
 use capnp_rpc::{rpc_twoparty_capnp::Side, twoparty, RpcSystem};
+use clap::crate_name;
 use conmon_common::conmon_capnp::conmon;
 use futures::{AsyncReadExt, FutureExt};
 use getset::Getters;
@@ -58,8 +59,8 @@ impl Server {
             process::exit(0);
         }
 
-        server.init_logging().context("set log verbosity")?;
         server.config().validate().context("validate config")?;
+        server.init_logging().context("init logging")?;
 
         Self::init().context("init self")?;
         Ok(server)
@@ -108,30 +109,47 @@ impl Server {
             LevelFilter::from_str(self.config().log_level()).context("convert log level filter")?;
         let registry = tracing_subscriber::registry();
 
-        match self.config().log_driver() {
-            LogDriver::Stdout => {
-                let layer = tracing_subscriber::fmt::layer()
-                    .with_target(true)
-                    .with_line_number(true)
-                    .with_filter(level);
-                registry
-                    .with(layer)
-                    .try_init()
-                    .context("init stdout fmt layer")?;
-                info!("Using stdout logger");
-            }
-            LogDriver::Systemd => {
-                let layer = tracing_journald::layer()
-                    .context("unable to connect to journald")?
-                    .with_filter(level);
-                registry
-                    .with(layer)
-                    .try_init()
-                    .context("init journald layer")?;
-                info!("Using systemd/journald logger");
-            }
-        }
+        let stdout = if self.config().log_drivers().contains(&LogDriver::Stdout) {
+            tracing_subscriber::fmt::layer()
+                .with_target(true)
+                .with_line_number(true)
+                .with_filter(level)
+                .into()
+        } else {
+            None
+        };
+
+        let systemd = if self.config().log_drivers().contains(&LogDriver::Systemd) {
+            tracing_journald::layer()
+                .context("unable to connect to journald")?
+                .with_filter(level)
+                .into()
+        } else {
+            None
+        };
+
+        let file = if self.config().log_drivers().contains(&LogDriver::File) {
+            let path = self.config().runtime_dir().join("logs");
+            let appender = tracing_appender::rolling::daily(path, crate_name!());
+            tracing_subscriber::fmt::layer()
+                .with_target(true)
+                .with_ansi(false)
+                .with_line_number(true)
+                .with_writer(appender)
+                .with_filter(level)
+                .into()
+        } else {
+            None
+        };
+
+        registry
+            .with(stdout)
+            .with(systemd)
+            .with(file)
+            .try_init()
+            .context("init registry")?;
         info!("Set log level to: {}", self.config().log_level());
+
         Ok(())
     }
 

pkg/client/client.go

@@ -57,9 +57,9 @@ type ConmonServerConfig struct {
 	// Can be "trace", "debug", "info", "warn", "error" or "off".
 	LogLevel string
 
-	// LogDriver is the possible server logging driver.
-	// Can be "stdout" or "systemd".
-	LogDriver string
+	// LogDrivers are the possible server logging drivers.
+	// Can be "stdout", "systemd" or both.
+	LogDrivers []string
 
 	// Runtime is the binary path of the OCI runtime to use to operate on the
 	// containers.
@@ -106,7 +106,7 @@ func NewConmonServerConfig(
 ) *ConmonServerConfig {
 	return &ConmonServerConfig{
 		LogLevel:     LogLevelDebug,
-		LogDriver:    LogDriverStdout,
+		LogDrivers:   []string{LogDriverStdout},
 		Runtime:      runtime,
 		RuntimeRoot:  runtimeRoot,
 		ServerRunDir: serverRunDir,
@@ -212,7 +212,7 @@ func (c *ConmonClient) startServer(config *ConmonServerConfig) error {
 		Setpgid: true,
 	}
 
-	if config.LogDriver == LogDriverStdout {
+	if contains(config.LogDrivers, LogDriverStdout) {
 		cmd.Stdout = os.Stdout
 		cmd.Stderr = os.Stderr
 		if config.Stdout != nil {
@@ -230,6 +230,16 @@ func (c *ConmonClient) startServer(config *ConmonServerConfig) error {
 	return nil
 }
 
+func contains[T comparable](haystack []T, needle T) bool {
+	for _, value := range haystack {
+		if value == needle {
+			return true
+		}
+	}
+
+	return false
+}
+
 func (c *ConmonClient) toArgs(config *ConmonServerConfig) (entrypoint string, args []string, err error) {
 	if c == nil {
 		return "", args, nil
@@ -263,11 +273,11 @@ func (c *ConmonClient) toArgs(config *ConmonServerConfig) (entrypoint string, ar
 		args = append(args, "--log-level", config.LogLevel)
 	}
 
-	if config.LogDriver != "" {
-		if err := validateLogDriver(config.LogDriver); err != nil {
+	for _, driver := range config.LogDrivers {
+		if err := validateLogDriver(driver); err != nil {
 			return "", args, fmt.Errorf("validate log driver: %w", err)
 		}
-		args = append(args, "--log-driver", config.LogDriver)
+		args = append(args, "--log-drivers", driver)
 	}
 
 	const cgroupManagerFlag = "--cgroup-manager"
@@ -297,7 +307,7 @@ func validateLogDriver(driver string) error {
 	return validateStringSlice(
 		"log driver",
 		driver,
-		LogDriverStdout, LogDriverSystemd,
+		LogDriverStdout, LogDriverSystemd, LogDriverFile,
 	)
 }
 

pkg/client/client_test.go

@@ -80,6 +80,15 @@ var _ = Describe("ConmonClient", func() {
 				} else {
 					Expect(version.CargoTree).To(BeEmpty())
 				}
+
+				// Validate the log file
+				logPath := filepath.Join(tr.tmpDir, "logs")
+				files, err := os.ReadDir(logPath)
+				Expect(err).To(BeNil())
+				Expect(files).To(HaveLen(1))
+				content, err := os.ReadFile(filepath.Join(logPath, files[0].Name()))
+				Expect(err).To(BeNil())
+				Expect(string(content)).To(ContainSubstring("Got a version request"))
 			})
 		}
 	})

pkg/client/consts.go

@@ -7,6 +7,11 @@ const (
 	// LogDriverSystemd is the log driver printing to systemd journald.
 	LogDriverSystemd = "systemd"
 
+	// LogDriverFile is the file based log driver. The log file path fill be
+	// generated to match / `[config.ServerRunDir]/logs/conmonrs.YYYY-MM-DD`
+	// and rotates on a daily basis.
+	LogDriverFile = "file"
+
 	// LogLevelTrace is the log level printing only "trace" messages.
 	LogLevelTrace = "trace"
 

pkg/client/suite_test.go

@@ -212,6 +212,7 @@ func (tr *testRunner) configGivenEnv() *client.ConmonClient {
 	logger := logrus.StandardLogger()
 	logger.Level = logrus.TraceLevel
 	cfg.ClientLogger = logger
+	cfg.LogDrivers = []string{client.LogDriverStdout, client.LogDriverFile}
 
 	sut, err := client.New(cfg)
 	Expect(err).To(BeNil())