added config.rs changes from hadron

compute_tools/src/config.rs

@@ -7,11 +7,14 @@ use std::io::prelude::*;
 use std::path::Path;
 
 use compute_api::responses::TlsConfig;
-use compute_api::spec::{ComputeAudit, ComputeMode, ComputeSpec, GenericOption};
+use compute_api::spec::{
+    ComputeAudit, ComputeMode, ComputeSpec, DatabricksSettings, GenericOption,
+};
 
 use crate::compute::ComputeNodeParams;
 use crate::pg_helpers::{
-    GenericOptionExt, GenericOptionsSearch, PgOptionsSerialize, escape_conf_value,
+    DatabricksSettingsExt, GenericOptionExt, GenericOptionsSearch, PgOptionsSerialize,
+    escape_conf_value,
 };
 use crate::tls::{self, SERVER_CRT, SERVER_KEY};
 
@@ -44,8 +47,10 @@ pub fn write_postgres_conf(
     pgdata_path: &Path,
     params: &ComputeNodeParams,
     spec: &ComputeSpec,
+    postgres_port: u16,
     extension_server_port: u16,
     tls_config: &Option<TlsConfig>,
+    databricks_settings: Option<&DatabricksSettings>,
 ) -> Result<()> {
     let path = pgdata_path.join("postgresql.conf");
     // File::create() destroys the file content if it exists.
@@ -285,6 +290,21 @@ pub fn write_postgres_conf(
         writeln!(file, "log_destination='stderr,syslog'")?;
     }
 
+    // Explicitly set the port based on the connstr, overriding any previous port setting.
+    // Note: It is important that we don't specify a different port again after this.
+    writeln!(file, "port = {}", postgres_port)?;
+
+    // This is databricks specific settings.
+    // This should be at the end of the file but before `compute_ctl_temp_override.conf` below
+    // so that it can override any settings above.
+    // `compute_ctl_temp_override.conf` is intended to override any settings above during specific operations.
+    // To prevent potential breakage in the future, we keep it above `compute_ctl_temp_override.conf`.
+    writeln!(file, "# Databricks settings start")?;
+    if let Some(settings) = databricks_settings {
+        writeln!(file, "{}", settings.as_pg_settings())?;
+    }
+    writeln!(file, "# Databricks settings end")?;
+
     // This is essential to keep this line at the end of the file,
     // because it is intended to override any settings above.
     writeln!(file, "include_if_exists = 'compute_ctl_temp_override.conf'")?;