Add support for --show-trace

src/command/apply.rs

@@ -33,11 +33,11 @@ pub fn subcommand() -> App<'static, 'static> {
             .long_help("Deactivates the progress spinner and prints every line of output.")
             .takes_value(false));
 
-    util::register_common_args(command)
+    util::register_selector_args(command)
 }
 
 pub async fn run(_global_args: &ArgMatches<'_>, local_args: &ArgMatches<'_>) {
-    let mut hive = Hive::from_config_arg(local_args).unwrap();
+    let mut hive = Hive::from_args(local_args).unwrap();
 
     println!("Enumerating nodes...");
     let all_nodes = hive.deployment_info().await.unwrap();

src/command/apply_local.rs

@@ -6,9 +6,10 @@ use tokio::process::Command;
 
 use crate::nix::{Hive, DeploymentTask, DeploymentGoal, Host};
 use crate::nix::host;
+use crate::util;
 
 pub fn subcommand() -> App<'static, 'static> {
-    SubCommand::with_name("apply-local")
+    let command = SubCommand::with_name("apply-local")
         .about("Apply configurations on the local machine")
         .arg(Arg::with_name("goal")
             .help("Deployment goal")
@@ -29,7 +30,9 @@ pub fn subcommand() -> App<'static, 'static> {
         .arg(Arg::with_name("we-are-launched-by-sudo")
             .long("we-are-launched-by-sudo")
             .hidden(true)
-            .takes_value(false))
+            .takes_value(false));
+
+    util::register_common_args(command)
 }
 
 pub async fn run(_global_args: &ArgMatches<'_>, local_args: &ArgMatches<'_>) {
@@ -62,7 +65,7 @@ pub async fn run(_global_args: &ArgMatches<'_>, local_args: &ArgMatches<'_>) {
         }
     }
 
-    let mut hive = Hive::from_config_arg(local_args).unwrap();
+    let mut hive = Hive::from_args(local_args).unwrap();
     let hostname = hostname::get().expect("Could not get hostname")
         .to_string_lossy().into_owned();
     let goal = DeploymentGoal::from_str(local_args.value_of("goal").unwrap()).unwrap();

src/command/build.rs

@@ -13,11 +13,11 @@ pub fn subcommand() -> App<'static, 'static> {
             .long_help("Deactivates the progress spinner and prints every line of output.")
             .takes_value(false));
 
-    util::register_common_args(command)
+    util::register_selector_args(command)
 }
 
 pub async fn run(_global_args: &ArgMatches<'_>, local_args: &ArgMatches<'_>) {
-    let mut hive = Hive::from_config_arg(local_args).unwrap();
+    let mut hive = Hive::from_args(local_args).unwrap();
 
     println!("Enumerating nodes...");
     let all_nodes = hive.deployment_info().await.unwrap();

src/command/introspect.rs

@@ -3,6 +3,7 @@ use std::path::PathBuf;
 use clap::{Arg, App, SubCommand, ArgMatches};
 
 use crate::nix::Hive;
+use crate::util;
 
 pub fn subcommand() -> App<'static, 'static> {
     let command = SubCommand::with_name("introspect")
@@ -29,11 +30,11 @@ For example, to retrieve the configuration of one node, you may write something
             .required(true))
         ;
 
-    command
+    util::register_common_args(command)
 }
 
 pub async fn run(_global_args: &ArgMatches<'_>, local_args: &ArgMatches<'_>) {
-    let mut hive = Hive::from_config_arg(local_args).unwrap();
+    let mut hive = Hive::from_args(local_args).unwrap();
 
     if !(local_args.is_present("expression") ^ local_args.is_present("expression_file")) {
         eprintln!("Either an expression (-E) xor a .nix file containing an expression should be specified, not both.");

src/nix/mod.rs

@@ -56,6 +56,7 @@ pub struct Hive {
     hive: PathBuf,
     eval_nix: TempPath,
     builder: Box<dyn Host>,
+    show_trace: bool,
 }
 
 impl Hive {
@@ -67,14 +68,21 @@ impl Hive {
             hive: hive.as_ref().to_owned(),
             eval_nix: eval_nix.into_temp_path(),
             builder: host::local(),
+            show_trace: false,
         })
     }
 
-    pub fn from_config_arg(args: &ArgMatches<'_>) -> NixResult<Self> {
+    pub fn from_args(args: &ArgMatches<'_>) -> NixResult<Self> {
         let path = args.value_of("config").expect("The config arg should exist").to_owned();
         let path = canonicalize_path(path);
 
-        Self::new(path)
+        let mut hive = Self::new(path)?;
+
+        if args.is_present("show-trace") {
+            hive.show_trace = true;
+        }
+
+        Ok(hive)
     }
 
     /// Retrieve deployment info for all nodes
@@ -126,7 +134,7 @@ impl Hive {
     }
 
     fn nix_instantiate(&self, expression: &str) -> NixInstantiate {
-        NixInstantiate::new(&self.eval_nix, &self.hive, expression.to_owned())
+        NixInstantiate::new(&self, expression.to_owned())
     }
 }
 
@@ -218,17 +226,15 @@ impl DeploymentGoal {
 }
 
 struct NixInstantiate<'hive> {
-    eval_nix: &'hive Path,
-    hive: &'hive Path,
+    hive: &'hive Hive,
     expression: String,
 }
 
 impl<'hive> NixInstantiate<'hive> {
-    fn new(eval_nix: &'hive Path, hive: &'hive Path, expression: String) -> Self {
+    fn new(hive: &'hive Hive, expression: String) -> Self {
         Self {
-            eval_nix,
-            expression,
             hive,
+            expression,
         }
     }
 
@@ -242,10 +248,15 @@ impl<'hive> NixInstantiate<'hive> {
             .arg("-E")
             .arg(format!(
                 "with builtins; let eval = import {}; hive = eval {{ rawHive = import {}; }}; in {}",
-                self.eval_nix.to_str().unwrap(),
-                self.hive.to_str().unwrap(),
+                self.hive.eval_nix.to_str().unwrap(),
+                self.hive.hive.to_str().unwrap(),
                 self.expression,
             ));
+
+        if self.hive.show_trace {
+            command.arg("--show-trace");
+        }
+
         command
     }
 

src/util.rs

@@ -56,6 +56,17 @@ pub fn register_common_args<'a, 'b>(command: App<'a, 'b>) -> App<'a, 'b> {
             .help("Path to a Hive expression")
             .default_value("hive.nix")
             .required(true))
+        .arg(Arg::with_name("show-trace")
+            .long("show-trace")
+            .help("Show debug information for Nix commands")
+            .long_help("Passes --show-trace to Nix commands")
+            .takes_value(false))
+}
+
+pub fn register_selector_args<'a, 'b>(command: App<'a, 'b>) -> App<'a, 'b> {
+    let command = register_common_args(command);
+
+    command
         .arg(Arg::with_name("on")
             .long("on")
             .help("Select a list of machines")