Complete Chapter 4

+ Add in Tracing Logging
+ Logs are JSON formatted with events
+ Tests are confirmed working

Cargo.lock

@@ -1160,11 +1160,14 @@ dependencies = [
  "actix-web",
  "chrono",
  "config",
+ "once_cell",
  "reqwest",
+ "secrecy",
  "serde",
  "sqlx",
  "tokio",
  "tracing",
+ "tracing-actix-web",
  "tracing-bunyan-formatter",
  "tracing-log 0.1.4",
  "tracing-subscriber",
@@ -1228,6 +1231,12 @@ dependencies = [
  "windows-sys 0.48.0",
 ]
 
+[[package]]
+name = "mutually_exclusive_features"
+version = "0.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6d02c0b00610773bb7fc61d85e13d86c7858cbdf00e1a120bfc41bc055dbaa0e"
+
 [[package]]
 name = "native-tls"
 version = "0.2.11"
@@ -1450,6 +1459,26 @@ version = "2.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9b2a4787296e9989611394c33f193f676704af1686e70b8f8033ab5ba9a35a94"
 
+[[package]]
+name = "pin-project"
+version = "1.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b6bf43b791c5b9e34c3d182969b4abb522f9343702850a2e57f460d00d09b4b3"
+dependencies = [
+ "pin-project-internal",
+]
+
+[[package]]
+name = "pin-project-internal"
+version = "1.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2f38a4412a78282e09a2cf38d195ea5420d15ba0602cb375210efbc877243965"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.32",
+]
+
 [[package]]
 name = "pin-project-lite"
 version = "0.2.13"
@@ -1772,6 +1801,16 @@ dependencies = [
  "untrusted 0.7.1",
 ]
 
+[[package]]
+name = "secrecy"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9bd1c54ea06cfd2f6b63219704de0b9b4f72dcc2b8fdef820be6cd799780e91e"
+dependencies = [
+ "serde",
+ "zeroize",
+]
+
 [[package]]
 name = "security-framework"
 version = "2.9.2"
@@ -2381,6 +2420,19 @@ dependencies = [
  "tracing-core",
 ]
 
+[[package]]
+name = "tracing-actix-web"
+version = "0.7.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fa069bd1503dd526ee793bb3fce408895136c95fc86d2edb2acf1c646d7f0684"
+dependencies = [
+ "actix-web",
+ "mutually_exclusive_features",
+ "pin-project",
+ "tracing",
+ "uuid",
+]
+
 [[package]]
 name = "tracing-attributes"
 version = "0.1.27"
@@ -2536,9 +2588,9 @@ checksum = "daf8dba3b7eb870caf1ddeed7bc9d2a049f3cfdfae7cb521b087cc33ae4c49da"
 
 [[package]]
 name = "uuid"
-version = "1.4.1"
+version = "1.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "79daa5ed5740825c40b389c5e50312b9c86df53fccd33f281df655642b43869d"
+checksum = "f00cc9702ca12d3c81455259621e676d0f7251cec66a21e98fe2e9a37db93b2a"
 dependencies = [
  "getrandom",
 ]

Cargo.toml

@@ -20,7 +20,9 @@ chrono = { version = "0.4.22", default-features = false, features = ["clock"] }
 tracing = { version = "0.1", features = ["log"] }
 tracing-subscriber = { version = "0.3", features = ["registry", "env-filter"] }
 tracing-bunyan-formatter = "0.3"
+tracing-actix-web = "0.7"
 tracing-log = "0.1"
+secrecy = { version = "0.8", features = ["serde"] }
 
 [dependencies.sqlx]
 version = "0.7"
@@ -36,3 +38,4 @@ features = [
 
 [dev-dependencies]
 reqwest = { version = "0.11", features = ["json"] }
+once_cell = "1"

src/configuration.rs

@@ -1,3 +1,5 @@
+use secrecy::{ExposeSecret, Secret};
+
 #[derive(serde::Deserialize)]
 pub struct Settings {
     pub database: DatabaseSettings,
@@ -7,7 +9,7 @@ pub struct Settings {
 #[derive(serde::Deserialize)]
 pub struct DatabaseSettings {
     pub username: String,
-    pub password: String,
+    pub password: Secret<String>,
     pub port: u16,
     pub host: String,
     pub database_name: String,
@@ -25,17 +27,24 @@ pub fn get_configuration() -> Result<Settings, config::ConfigError> {
 }
 
 impl DatabaseSettings {
-    pub fn connection_string(&self) -> String {
+    pub fn connection_string(&self) -> Secret<String> {
-        format!(
+        Secret::new(format!(
             "postgres://{}:{}@{}:{}/{}",
-            self.username, self.password, self.host, self.port, self.database_name
+            self.username,
-        )
+            self.password.expose_secret(),
+            self.host,
+            self.port,
+            self.database_name
+        ))
     }
 
-    pub fn connection_string_without_db(&self) -> String {
+    pub fn connection_string_without_db(&self) -> Secret<String> {
-        format!(
+        Secret::new(format!(
             "postgres://{}:{}@{}:{}",
-            self.username, self.password, self.host, self.port
+            self.username,
-        )
+            self.password.expose_secret(),
+            self.host,
+            self.port
+        ))
     }
 }

src/main.rs

@@ -1,16 +1,18 @@
 use mail_app::configuration::get_configuration;
 use mail_app::startup::run;
 use mail_app::telemetry::{get_subscriber, init_subscriber};
+use secrecy::ExposeSecret;
 use sqlx::postgres::PgPool;
 use std::net::TcpListener;
 
 #[tokio::main]
 async fn main() -> Result<(), std::io::Error> {
-    let subscriber = get_subscriber("mail_app".into(), "info".into());
+    let subscriber = get_subscriber("mail_app".into(), "info".into(), std::io::stdout);
     init_subscriber(subscriber);
 
     let configuration = get_configuration().expect("Failed to read configuration");
-    let connection_pool = PgPool::connect(&configuration.database.connection_string())
+    let connection_pool =
+        PgPool::connect(&configuration.database.connection_string().expose_secret())
             .await
             .expect("Failed to connect to Postgres.");
     let address = format!("127.0.0.1:{}", configuration.application_port);

src/routes/subscriptions.rs

@@ -1,7 +1,6 @@
 use actix_web::{web, HttpResponse};
 use chrono::Utc;
 use sqlx::PgPool;
-use tracing::Instrument;
 use uuid::Uuid;
 
 #[derive(serde::Deserialize)]
@@ -10,18 +9,29 @@ pub struct FormData {
     name: String,
 }
 
-pub async fn subscribe(form: web::Form<FormData>, pool: web::Data<PgPool>) -> HttpResponse {
+#[tracing::instrument(
-    let request_id = Uuid::new_v4();
+    name = "Adding a new subscriber",
-    let request_span = tracing::info_span!(
+    skip(form, pool),
-        "Adding a new subscriber.",
+    fields(
-        %request_id,
         subscriber_email = %form.email,
         subscriber_name = %form.name
-    );
+    )
+)]
 
-    let _request_span_guard = request_span.enter();
+pub async fn subscribe(form: web::Form<FormData>, pool: web::Data<PgPool>) -> HttpResponse {
-    let query_span = tracing::info_span!("Saving new subscriber details to database");
+    match insert_subscriber(&pool, &form).await {
-    match sqlx::query!(
+        Ok(_) => HttpResponse::Ok().finish(),
+        Err(_) => HttpResponse::InternalServerError().finish(),
+    }
+}
+
+#[tracing::instrument(
+    name = "Saving new subscriber details in the database",
+    skip(form, pool)
+)]
+
+pub async fn insert_subscriber(pool: &PgPool, form: &FormData) -> Result<(), sqlx::Error> {
+    sqlx::query!(
         r#"
         INSERT INTO subscriptions (id, email, name, subscribed_at)
         VALUES ($1, $2, $3, $4)
@@ -31,14 +41,11 @@ pub async fn subscribe(form: web::Form<FormData>, pool: web::Data<PgPool>) -> Ht
         form.name,
         Utc::now()
     )
-    .execute(pool.get_ref())
+    .execute(pool)
-    .instrument(query_span)
     .await
-    {
+    .map_err(|e| {
-        Ok(_) => HttpResponse::Ok().finish(),
-        Err(e) => {
         tracing::error!("Failed to execute query: {:?}", e);
-            HttpResponse::InternalServerError().finish()
+        e
-        }
+    })?;
-    }
+    Ok(())
 }

src/startup.rs

@@ -1,18 +1,18 @@
 use crate::routes::{health_check, subscribe};
 use actix_web::dev::Server;
-use actix_web::middleware::Logger;
+use actix_web::{web, web::Data, App, HttpServer};
-use actix_web::{web, App, HttpServer};
 use sqlx::PgPool;
 use std::net::TcpListener;
+use tracing_actix_web::TracingLogger;
 
 pub fn run(listener: TcpListener, db_pool: PgPool) -> Result<Server, std::io::Error> {
-    let connection = web::Data::new(db_pool);
+    let db_pool = Data::new(db_pool);
     let server = HttpServer::new(move || {
         App::new()
-            .wrap(Logger::default())
+            .wrap(TracingLogger::default())
             .route("/health_check", web::get().to(health_check))
             .route("/subscriptions", web::post().to(subscribe))
-            .app_data(connection.clone())
+            .app_data(db_pool.clone())
     })
     .listen(listener)?
     .run();

src/telemetry.rs

@@ -1,12 +1,19 @@
 use tracing::{subscriber::set_global_default, Subscriber};
 use tracing_bunyan_formatter::{BunyanFormattingLayer, JsonStorageLayer};
 use tracing_log::LogTracer;
-use tracing_subscriber::{layer::SubscriberExt, EnvFilter, Registry};
+use tracing_subscriber::{fmt::MakeWriter, layer::SubscriberExt, EnvFilter, Registry};
 
-pub fn get_subscriber(name: String, env_filter: String) -> impl Subscriber + Send + Sync {
+pub fn get_subscriber<Sink>(
+    name: String,
+    env_filter: String,
+    sink: Sink,
+) -> impl Subscriber + Send + Sync
+where
+    Sink: for<'a> MakeWriter<'a> + Send + Sync + 'static,
+{
     let env_filter =
         EnvFilter::try_from_default_env().unwrap_or_else(|_| EnvFilter::new(env_filter));
-    let formatting_layer = BunyanFormattingLayer::new(name, std::io::stdout);
+    let formatting_layer = BunyanFormattingLayer::new(name, sink);
     Registry::default()
         .with(env_filter)
         .with(JsonStorageLayer)

tests/health_check.rs

@@ -1,15 +1,32 @@
 use mail_app::configuration::{get_configuration, DatabaseSettings};
 use mail_app::startup::run;
+use mail_app::telemetry::{get_subscriber, init_subscriber};
+use once_cell::sync::Lazy;
+use secrecy::ExposeSecret;
 use sqlx::{Executor, PgPool};
 use std::net::TcpListener;
 use uuid::Uuid;
 
+static TRACING: Lazy<()> = Lazy::new(|| {
+    let default_filter_level = "info".to_string();
+    let subscriber_name = "test".to_string();
+    if std::env::var("TEST_LOG").is_ok() {
+        let subscriber = get_subscriber(subscriber_name, default_filter_level, std::io::stdout);
+        init_subscriber(subscriber);
+    } else {
+        let subscriber = get_subscriber(subscriber_name, default_filter_level, std::io::sink);
+        init_subscriber(subscriber);
+    };
+});
+
 pub struct TestApp {
     pub address: String,
     pub db_pool: PgPool,
 }
 
 async fn spawn_app() -> TestApp {
+    Lazy::force(&TRACING);
+
     let listener = TcpListener::bind("127.0.0.1:0").expect("Failed to bind to random port.");
     let port = listener.local_addr().unwrap().port();
     let address = format!("http://127.0.0.1:{}", port);
@@ -30,7 +47,7 @@ async fn spawn_app() -> TestApp {
 
 pub async fn configure_database(config: &DatabaseSettings) -> PgPool {
     // Create Database
-    let connection = PgPool::connect(&config.connection_string_without_db())
+    let connection = PgPool::connect(&config.connection_string_without_db().expose_secret())
         .await
         .expect("Failed to connect to Postgres.");
     connection
@@ -39,7 +56,7 @@ pub async fn configure_database(config: &DatabaseSettings) -> PgPool {
         .expect("Failed to create database.");
 
     // Migrate Database
-    let connection_pool = PgPool::connect(&config.connection_string())
+    let connection_pool = PgPool::connect(&config.connection_string().expose_secret())
         .await
         .expect("Failed to connect to Postgres.");
     sqlx::migrate!("./migrations")