feat(notary): Make logging format configurable (#719)

* Make logging format configurable

* Document logging format

* Fix formatting

* Init server config with default value
s in notary interation tests

crates/notary/server/Cargo.toml

@@ -54,7 +54,7 @@ tower-http = { version = "0.5", features = ["cors"] }
 tower-service = { version = "0.3" }
 tower-util = { version = "0.3.1" }
 tracing = { workspace = true }
-tracing-subscriber = { workspace = true, features = ["env-filter"] }
+tracing-subscriber = { workspace = true, features = ["env-filter", "json"] }
 uuid = { workspace = true, features = ["v4", "fast-rng"] }
 ws_stream_tungstenite = { workspace = true, features = ["tokio_io"] }
 zeroize = { workspace = true }

crates/notary/server/README.md

@@ -119,7 +119,9 @@ The default logging strategy of this server is set to `DEBUG` verbosity level fo
 
 In the config [file](./config/config.yaml), one can toggle the verbosity level for these crates using the `level` field under `logging`. Alternatively, use the CLI argument `--log-level` (see [this](#configuration)).
 
-One can also provide a custom filtering logic by adding a `filter` field  under `logging` in the config file above, and use a value that follows the tracing crate's [filter directive syntax](https://docs.rs/tracing-subscriber/latest/tracing_subscriber/filter/struct.EnvFilter.html#example-syntax).
+One can also provide a custom filtering logic by adding a `filter` field under `logging` in the config file above, and use a value that follows the tracing crate's [filter directive syntax](https://docs.rs/tracing-subscriber/latest/tracing_subscriber/filter/struct.EnvFilter.html#example-syntax).
+
+Logs can be printed in two formats. Compact and JSON. Compact is human-readable and is best suited for console. JSON is machine-readable and is used to send logs to log collection services. One can change log format by switching the `format` field under `logging`. Accepted values are `compact` and `json`. If the config key is not set - `compact` is used by default.
 
 ---
 ## Architecture

crates/notary/server/src/config.rs

@@ -71,4 +71,16 @@ pub struct LoggingProperties {
     /// Custom filtering logic, refer to the syntax here https://docs.rs/tracing-subscriber/latest/tracing_subscriber/filter/struct.EnvFilter.html#example-syntax
     /// This will override the default filtering logic above
     pub filter: Option<String>,
+    /// Log format. Available options are "compact" and "json". Default is
+    /// "compact"
+    #[serde(default)]
+    pub format: LogFormat,
+}
+
+#[derive(Clone, Copy, Debug, Deserialize, Default)]
+#[serde(rename_all = "kebab-case")]
+pub enum LogFormat {
+    #[default]
+    Compact,
+    Json,
 }

crates/notary/server/src/server_tracing.rs

@@ -1,9 +1,23 @@
 use eyre::Result;
 use std::str::FromStr;
-use tracing::Level;
-use tracing_subscriber::{layer::SubscriberExt, util::SubscriberInitExt, EnvFilter, Registry};
+use tracing::{Level, Subscriber};
+use tracing_subscriber::{
+    fmt, layer::SubscriberExt, registry::LookupSpan, util::SubscriberInitExt, EnvFilter, Layer,
+    Registry,
+};
 
-use crate::config::NotaryServerProperties;
+use crate::config::{LogFormat, NotaryServerProperties};
+
+fn format_layer<S>(format: LogFormat) -> Box<dyn Layer<S> + Send + Sync>
+where
+    S: Subscriber + for<'a> LookupSpan<'a>,
+{
+    let f = fmt::layer().with_thread_ids(true).with_thread_names(true);
+    match format {
+        LogFormat::Compact => f.compact().boxed(),
+        LogFormat::Json => f.json().boxed(),
+    }
+}
 
 pub fn init_tracing(config: &NotaryServerProperties) -> Result<()> {
     // Retrieve log filtering logic from config
@@ -18,16 +32,9 @@ pub fn init_tracing(config: &NotaryServerProperties) -> Result<()> {
     };
     let filter_layer = EnvFilter::builder().parse(directives)?;
 
-    // Format the log
-    let format_layer = tracing_subscriber::fmt::layer()
-        // Use a more compact, abbreviated log format
-        .compact()
-        .with_thread_ids(true)
-        .with_thread_names(true);
-
     Registry::default()
         .with(filter_layer)
-        .with(format_layer)
+        .with(format_layer(config.logging.format))
         .try_init()?;
 
     Ok(())

crates/notary/tests-integration/tests/notary.rs

@@ -61,7 +61,7 @@ fn get_server_config(port: u16, tls_enabled: bool, auth_enabled: bool) -> Notary
         },
         logging: LoggingProperties {
             level: "DEBUG".to_string(),
-            filter: None,
+            ..Default::default()
         },
         authorization: AuthorizationProperties {
             enabled: auth_enabled,