track seconds elapsed since server startup

crates/service/web/storyteller_web/src/http_server/endpoints/service/health_check_handler.rs

@@ -4,7 +4,8 @@ use std::sync::Arc;
 use actix_web::error::ResponseError;
 use actix_web::http::StatusCode;
 use actix_web::{web, HttpRequest, HttpResponse};
-use chrono::NaiveDateTime;
+use actix_web::web::Json;
+use chrono::{DateTime, NaiveDateTime, Utc};
 use log::error;
 
 use http_server_common::response::serialize_as_json_error::serialize_as_json_error;
@@ -22,6 +23,8 @@ pub struct HealthCheckResponse {
   pub unhealthy_check_consecutive_count: Option<u64>,
   pub server_build_sha: String,
   pub server_hostname: String,
+  pub startup_time: DateTime<Utc>,
+  pub seconds_since_startup: u64,
 }
 
 
@@ -65,6 +68,11 @@ pub async fn get_health_check_handler(
 
   let is_healthy = health_check_status.is_healthy;
 
+  let now = Utc::now();
+  let seconds_since_startup = now.signed_duration_since(server_state.startup_time)
+      .num_seconds()
+      .unsigned_abs();
+
   let response = HealthCheckResponse {
     success: true,
     is_healthy: health_check_status.is_healthy,
@@ -73,6 +81,8 @@ pub async fn get_health_check_handler(
     unhealthy_check_consecutive_count: health_check_status.unhealthy_check_consecutive_count,
     server_build_sha: server_state.server_info.build_sha.clone(),
     server_hostname: server_state.hostname.clone(),
+    startup_time: server_state.startup_time,
+    seconds_since_startup,
   };
 
   let body = serde_json::to_string(&response)

crates/service/web/storyteller_web/src/main.rs

@@ -25,6 +25,7 @@ use actix_multipart::form::MultipartFormConfig;
 use actix_web::middleware::{DefaultHeaders, Logger};
 use actix_web::{middleware, web, App, HttpServer};
 use anyhow::anyhow;
+use chrono::Utc;
 use elasticsearch::http::transport::Transport;
 use elasticsearch::Elasticsearch;
 use log::info;
@@ -392,6 +393,8 @@ async fn main() -> AnyhowResult<()> {
 
   let openai_api_key= easyenv::get_env_string_required("OPENAI_API_KEY")?;
 
+  let startup_time = Utc::now();
+
   let server_state = ServerState {
     env_config: EnvConfig {
       num_workers,
@@ -409,6 +412,7 @@ async fn main() -> AnyhowResult<()> {
       client: stripe_client,
     },
     hostname: server_hostname,
+    startup_time,
     server_environment_old: server_environment,
     server_environment: server_environment_typed,
     flags: service_feature_flags,

crates/service/web/storyteller_web/src/state/server_state.rs

@@ -1,3 +1,4 @@
+use chrono::{DateTime, Utc};
 use elasticsearch::Elasticsearch;
 use r2d2_redis::{r2d2, RedisConnectionManager};
 use sqlx::MySqlPool;
@@ -51,6 +52,9 @@ pub struct ServerState {
 
   pub hostname: String,
 
+  /// When the server starts.
+  pub startup_time: DateTime<Utc>,
+
   #[deprecated(note = "Use `server_environment` instead")]
   /// Knowing if we're in production will allow us to turn off development-only functionalities.
   pub server_environment_old: ServerEnvironment,