Add logging of installed_extensions (#9438)

Simple PR to log installed_extensions statistics.

in the following format:
```
2024-10-17T13:53:02.860595Z  INFO [NEON_EXT_STAT] {"extensions":[{"extname":"plpgsql","versions":["1.0"],"n_databases":2},{"extname":"neon","versions":["1.5"],"n_databases":1}]}
```

compute_tools/src/compute.rs

@@ -34,6 +34,7 @@ use nix::sys::signal::{kill, Signal};
 use remote_storage::{DownloadError, RemotePath};
 
 use crate::checker::create_availability_check_data;
+use crate::installed_extensions::get_installed_extensions_sync;
 use crate::local_proxy;
 use crate::logger::inlinify;
 use crate::pg_helpers::*;
@@ -1121,6 +1122,11 @@ impl ComputeNode {
                 self.pg_reload_conf()?;
             }
             self.post_apply_config()?;
+
+            let connstr = self.connstr.clone();
+            thread::spawn(move || {
+                get_installed_extensions_sync(connstr).context("get_installed_extensions")
+            });
         }
 
         let startup_end_time = Utc::now();
@@ -1484,28 +1490,6 @@ LIMIT 100",
             info!("Pageserver config changed");
         }
     }
-
-    // Gather info about installed extensions
-    pub fn get_installed_extensions(&self) -> Result<()> {
-        let connstr = self.connstr.clone();
-
-        let rt = tokio::runtime::Builder::new_current_thread()
-            .enable_all()
-            .build()
-            .expect("failed to create runtime");
-        let result = rt
-            .block_on(crate::installed_extensions::get_installed_extensions(
-                connstr,
-            ))
-            .expect("failed to get installed extensions");
-
-        info!(
-            "{}",
-            serde_json::to_string(&result).expect("failed to serialize extensions list")
-        );
-
-        Ok(())
-    }
 }
 
 pub fn forward_termination_signal() {

compute_tools/src/installed_extensions.rs

@@ -1,6 +1,7 @@
 use compute_api::responses::{InstalledExtension, InstalledExtensions};
 use std::collections::HashMap;
 use std::collections::HashSet;
+use tracing::info;
 use url::Url;
 
 use anyhow::Result;
@@ -79,3 +80,23 @@ pub async fn get_installed_extensions(connstr: Url) -> Result<InstalledExtension
     })
     .await?
 }
+
+// Gather info about installed extensions
+pub fn get_installed_extensions_sync(connstr: Url) -> Result<()> {
+    let rt = tokio::runtime::Builder::new_current_thread()
+        .enable_all()
+        .build()
+        .expect("failed to create runtime");
+    let result = rt
+        .block_on(crate::installed_extensions::get_installed_extensions(
+            connstr,
+        ))
+        .expect("failed to get installed extensions");
+
+    info!(
+        "[NEON_EXT_STAT] {}",
+        serde_json::to_string(&result).expect("failed to serialize extensions list")
+    );
+
+    Ok(())
+}