refactor(common): allow custom default configs (#6068)

Description
---
Adds `load_configuration_with_overrides` that exposes the functionality
to load configs without including the prompting and compiled in config
templates.

Motivation and Context
---
On the tari-dan repo, we want to customize the default configurations
without having to PR to the tari repo. L2-related configs can be managed
in the tari-dan repo and can be removed from this repo in a subsequent
PR.

How Has This Been Tested?
---
Manually by starting a new base node and checking the config.toml

What process can a PR reviewer use to test or verify this change?
---
Base node default config works as before

Breaking Changes
---

- [x] None
- [ ] Requires data directory on base node to be deleted
- [ ] Requires hard fork
- [ ] Other - Please specify

<!-- Does this include a breaking change? If so, include this line as a
footer -->
<!-- BREAKING CHANGE: Description what the user should do, e.g. delete a
database, resync the chain -->

Co-authored-by: SW van Heerden <swvheerden@gmail.com>

common/src/configuration/utils.rs

@@ -20,6 +20,8 @@ use crate::{
 
 //-------------------------------------           Main API functions         --------------------------------------//
 
+/// Loads the configuration file from the specified path, or creates a new one with the embedded default presets if it
+/// does not. This also prompts the user.
 pub fn load_configuration<P: AsRef<Path>, TOverride: ConfigOverrideProvider>(
     config_path: P,
     create_if_not_exists: bool,
@@ -29,12 +31,26 @@ pub fn load_configuration<P: AsRef<Path>, TOverride: ConfigOverrideProvider>(
     debug!(
         target: LOG_TARGET,
         "Loading configuration file from  {}",
-        config_path.as_ref().to_str().unwrap_or("[??]")
+        config_path.as_ref().display()
     );
     if !config_path.as_ref().exists() && create_if_not_exists {
-        write_default_config_to(&config_path, non_interactive)
+        let sources = if non_interactive {
+            get_default_config(false)
+        } else {
+            prompt_default_config()
+        };
+        write_config_to(&config_path, &sources)
             .map_err(|io| ConfigError::new("Could not create default config", Some(io.to_string())))?;
     }
+
+    load_configuration_with_overrides(config_path, overrides)
+}
+
+/// Loads the config at the given path applying all overrides.
+pub fn load_configuration_with_overrides<P: AsRef<Path>, TOverride: ConfigOverrideProvider>(
+    config_path: P,
+    overrides: &TOverride,
+) -> Result<Config, ConfigError> {
     let filename = config_path
         .as_ref()
         .to_str()
@@ -84,27 +100,28 @@ pub fn load_configuration<P: AsRef<Path>, TOverride: ConfigOverrideProvider>(
     Ok(cfg)
 }
 
-/// Installs a new configuration file template, copied from the application type's preset and written to the given path.
+/// Returns a new configuration file template in parts from the embedded presets. If non_interactive is false, the user
+/// is prompted to select if they would like to select a base node configuration that enables mining or not.
 /// Also includes the common configuration defined in `config/presets/common.toml`.
-pub fn write_default_config_to<P: AsRef<Path>>(path: P, non_interactive: bool) -> Result<(), std::io::Error> {
-    // Use the same config file so that all the settings are easier to find, and easier to
-    // support users over chat channels
-    let mine = if non_interactive {
-        false
-    } else {
-        prompt(
-            "Node config does not exist.\nWould you like to mine (Y/n)?\nNOTE: this will enable gprc methods that can \
-             leak private info on the node",
-        )
-    };
-    let base_node_deny_methods = if mine {
+pub fn prompt_default_config() -> [&'static str; 12] {
+    let mine = prompt(
+        "Node config does not exist.\nWould you like to mine (Y/n)?\nNOTE: this will enable additional gRPC methods \
+         that could be used to monitor and submit blocks from this node.",
+    );
+    get_default_config(mine)
+}
+
+/// Returns the default configuration file template in parts from the embedded presets. If use_mining_config is true,
+/// the base node configuration that enables mining is returned, otherwise the non-mining configuration is returned.
+pub fn get_default_config(use_mining_config: bool) -> [&'static str; 12] {
+    let base_node_deny_methods = if use_mining_config {
         include_str!("../../config/presets/c_base_node_b_mining_deny_methods.toml")
     } else {
         include_str!("../../config/presets/c_base_node_b_non_mining_deny_methods.toml")
     };
 
     let common = include_str!("../../config/presets/a_common.toml");
-    let source = [
+    [
         common,
         include_str!("../../config/presets/b_peer_seeds.toml"),
         include_str!("../../config/presets/c_base_node_a.toml"),
@@ -118,13 +135,20 @@ pub fn write_default_config_to<P: AsRef<Path>>(path: P, non_interactive: bool) -
         include_str!("../../config/presets/i_indexer.toml"),
         include_str!("../../config/presets/j_dan_wallet_daemon.toml"),
     ]
-    .join("\n");
+}
 
+/// Writes a single file concatenating all the provided sources to the specified path. If the parent directory does not
+/// exist, it is created. If the file already exists, it is overwritten.
+pub fn write_config_to<P: AsRef<Path>>(path: P, sources: &[&str]) -> Result<(), std::io::Error> {
     if let Some(d) = path.as_ref().parent() {
         fs::create_dir_all(d)?
     };
     let mut file = File::create(path)?;
-    file.write_all(source.as_ref())
+    for source in sources {
+        file.write_all(source.as_bytes())?;
+        file.write_all(b"\n")?;
+    }
+    Ok(())
 }
 
 pub fn serialize_string<S, T>(source: &T, ser: S) -> Result<S::Ok, S::Error>