Traverse up to find hive.nix by default, and other CLI ergonomics fixes

Cargo.lock

@@ -1,5 +1,14 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+[[package]]
+name = "aho-corasick"
+version = "0.7.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7404febffaa47dac81aa44dba71523c9d069b1bdc50a77db41195149e17f68e5"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "ansi_term"
 version = "0.11.0"
@@ -83,6 +92,7 @@ dependencies = [
  "async-trait",
  "clap",
  "console",
+ "env_logger",
  "futures",
  "glob",
  "hostname",
@@ -125,6 +135,19 @@ version = "0.3.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a357d28ed41a50f9c765dbfe56cbc04a64e53e5fc58ba79fbc34c10ef3df831f"
 
+[[package]]
+name = "env_logger"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f26ecb66b4bdca6c1409b40fb255eefc2bd4f6d135dab3c3124f80ffa2a9661e"
+dependencies = [
+ "atty",
+ "humantime",
+ "log",
+ "regex",
+ "termcolor",
+]
+
 [[package]]
 name = "futures"
 version = "0.3.8"
@@ -257,6 +280,12 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "humantime"
+version = "2.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3c1ad908cc71012b7bea4d0c53ba96a8cba9962f048fa68d143376143d863b7a"
+
 [[package]]
 name = "indicatif"
 version = "0.15.0"
@@ -541,7 +570,10 @@ version = "1.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "38cf2c13ed4745de91a5eb834e11c00bcc3709e773173b2ce4c56c9fbde04b9c"
 dependencies = [
+ "aho-corasick",
+ "memchr",
  "regex-syntax",
+ "thread_local",
 ]
 
 [[package]]
@@ -687,6 +719,15 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "termcolor"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2dfed899f0eb03f32ee8c6a0aabdb8a7949659e3466561fc0adf54e26d88c5f4"
+dependencies = [
+ "winapi-util",
+]
+
 [[package]]
 name = "terminal_size"
 version = "0.1.15"
@@ -706,6 +747,15 @@ dependencies = [
  "unicode-width",
 ]
 
+[[package]]
+name = "thread_local"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d40c6d1b69745a6ec6fb1ca717914848da4b44ae29d9b3080cbee91d72a69b14"
+dependencies = [
+ "lazy_static",
+]
+
 [[package]]
 name = "tokio"
 version = "1.0.0"

Cargo.toml

@@ -10,6 +10,7 @@ edition = "2018"
 async-trait = "0.1.42"
 clap = "2.33.3"
 console = "0.13.0"
+env_logger = "0.8.2"
 futures = "0.3.8"
 glob = "0.3.0"
 hostname = "0.3.1"

default.nix

@@ -10,5 +10,5 @@ in rustPlatform.buildRustPackage {
   version = "0.1.0";
 
   src = ./.;
-  cargoSha256 = "0gwjbzvx6hlbjb8892rc2p9rj5l432y13aq1nxr2h71rgqppxflg";
+  cargoSha256 = "1ai046vbvydyqhwiy8qz0d28dch5jpxg3rzk7nrh2sdwcvxirmvm";
 }

src/command/apply.rs

@@ -1,6 +1,6 @@
 use clap::{Arg, App, SubCommand, ArgMatches};
 
-use crate::nix::{Hive, DeploymentTask, DeploymentGoal};
+use crate::nix::{DeploymentTask, DeploymentGoal};
 use crate::deployment::deploy;
 use crate::util;
 
@@ -37,9 +37,9 @@ pub fn subcommand() -> App<'static, 'static> {
 }
 
 pub async fn run(_global_args: &ArgMatches<'_>, local_args: &ArgMatches<'_>) {
-    let mut hive = Hive::from_args(local_args).unwrap();
+    let mut hive = util::hive_from_args(local_args).unwrap();
 
-    println!("Enumerating nodes...");
+    log::info!("Enumerating nodes...");
     let all_nodes = hive.deployment_info().await.unwrap();
 
     let selected_nodes = match local_args.value_of("on") {
@@ -50,14 +50,14 @@ pub async fn run(_global_args: &ArgMatches<'_>, local_args: &ArgMatches<'_>) {
     };
 
     if selected_nodes.len() == 0 {
-        println!("No hosts matched. Exiting...");
+        log::warn!("No hosts matched. Exiting...");
         quit::with_code(2);
     }
 
     if selected_nodes.len() == all_nodes.len() {
-        println!("Building all node configurations...");
+        log::info!("Building all node configurations...");
     } else {
-        println!("Selected {} out of {} hosts. Building node configurations...", selected_nodes.len(), all_nodes.len());
+        log::info!("Selected {} out of {} hosts. Building node configurations...", selected_nodes.len(), all_nodes.len());
     }
 
     // Some ugly argument mangling :/
@@ -88,9 +88,9 @@ pub async fn run(_global_args: &ArgMatches<'_>, local_args: &ArgMatches<'_>) {
     }
 
     if skip_list.len() != 0 {
-        println!("Applying configurations ({} skipped)...", skip_list.len());
+        log::info!("Applying configurations ({} skipped)...", skip_list.len());
     } else {
-        println!("Applying configurations...");
+        log::info!("Applying configurations...");
     }
 
     deploy(task_list, max_parallelism, !verbose).await;

src/command/apply_local.rs

@@ -4,12 +4,12 @@ use clap::{Arg, App, SubCommand, ArgMatches};
 use tokio::fs;
 use tokio::process::Command;
 
-use crate::nix::{Hive, DeploymentTask, DeploymentGoal, Host};
+use crate::nix::{DeploymentTask, DeploymentGoal, Host};
 use crate::nix::host;
 use crate::util;
 
 pub fn subcommand() -> App<'static, 'static> {
-    let command = SubCommand::with_name("apply-local")
+    SubCommand::with_name("apply-local")
         .about("Apply configurations on the local machine")
         .arg(Arg::with_name("goal")
             .help("Deployment goal")
@@ -17,12 +17,6 @@ pub fn subcommand() -> App<'static, 'static> {
             .default_value("switch")
             .index(1)
             .possible_values(&["push", "switch", "boot", "test", "dry-activate"]))
-        .arg(Arg::with_name("config")
-            .short("f")
-            .long("config")
-            .help("Path to a Hive expression")
-            .default_value("hive.nix")
-            .required(true))
         .arg(Arg::with_name("sudo")
             .long("sudo")
             .help("Attempt to escalate privileges if not run as root")
@@ -30,20 +24,18 @@ 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<'_>) {
     // Sanity check: Are we running NixOS?
     if let Ok(os_release) = fs::read_to_string("/etc/os-release").await {
         if !os_release.contains("ID=nixos\n") {
-            eprintln!("\"apply-local\" only works on NixOS machines.");
+            log::error!("\"apply-local\" only works on NixOS machines.");
             quit::with_code(5);
         }
     } else {
-        eprintln!("Coult not detect the OS version from /etc/os-release.");
+        log::error!("Coult not detect the OS version from /etc/os-release.");
         quit::with_code(5);
     }
 
@@ -52,42 +44,42 @@ pub async fn run(_global_args: &ArgMatches<'_>, local_args: &ArgMatches<'_>) {
         let euid: u32 = unsafe { libc::geteuid() };
         if euid != 0 {
             if local_args.is_present("we-are-launched-by-sudo") {
-                eprintln!("Failed to escalate privileges. We are still not root despite a successful sudo invocation.");
+                log::error!("Failed to escalate privileges. We are still not root despite a successful sudo invocation.");
                 quit::with_code(3);
             }
 
             if local_args.is_present("sudo") {
                 escalate().await;
             } else {
-                eprintln!("Colmena was not started by root. This is probably not going to work.");
+                log::warn!("Colmena was not started by root. This is probably not going to work.");
-                eprintln!("Hint: Add the --sudo flag.");
+                log::warn!("Hint: Add the --sudo flag.");
             }
         }
     }
 
-    let mut hive = Hive::from_args(local_args).unwrap();
+    let mut hive = util::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();
 
-    println!("Enumerating nodes...");
+    log::info!("Enumerating nodes...");
     let all_nodes = hive.deployment_info().await.unwrap();
 
     let target: Box<dyn Host> = {
         if let Some(info) = all_nodes.get(&hostname) {
             if !info.allows_local_deployment() {
-                eprintln!("Local deployment is not enabled for host {}.", hostname);
+                log::error!("Local deployment is not enabled for host {}.", hostname);
-                eprintln!("Hint: Set deployment.allowLocalDeployment to true.");
+                log::error!("Hint: Set deployment.allowLocalDeployment to true.");
                 quit::with_code(2);
             }
             host::local()
         } else {
-            eprintln!("Host {} is not present in the Hive configuration.", hostname);
+            log::error!("Host {} is not present in the Hive configuration.", hostname);
             quit::with_code(2);
         }
     };
 
-    println!("Building local node configuration...");
+    log::info!("Building local node configuration...");
     let profile = {
         let selected_nodes: Vec<String> = vec![hostname.clone()];
         let mut profiles = hive.build_selected(selected_nodes).await

src/command/build.rs

@@ -1,6 +1,5 @@
 use clap::{Arg, App, SubCommand, ArgMatches};
 
-use crate::nix::Hive;
 use crate::util;
 
 pub fn subcommand() -> App<'static, 'static> {
@@ -17,9 +16,9 @@ pub fn subcommand() -> App<'static, 'static> {
 }
 
 pub async fn run(_global_args: &ArgMatches<'_>, local_args: &ArgMatches<'_>) {
-    let mut hive = Hive::from_args(local_args).unwrap();
+    let mut hive = util::hive_from_args(local_args).unwrap();
 
-    println!("Enumerating nodes...");
+    log::info!("Enumerating nodes...");
     let all_nodes = hive.deployment_info().await.unwrap();
 
     let selected_nodes = match local_args.value_of("on") {
@@ -30,17 +29,17 @@ pub async fn run(_global_args: &ArgMatches<'_>, local_args: &ArgMatches<'_>) {
     };
 
     if selected_nodes.len() == 0 {
-        println!("No hosts matched. Exiting...");
+        log::warn!("No hosts matched. Exiting...");
         quit::with_code(2);
     }
 
     if selected_nodes.len() == all_nodes.len() {
-        println!("Building all node configurations...");
+        log::info!("Building all node configurations...");
     } else {
-        println!("Selected {} out of {} hosts. Building node configurations...", selected_nodes.len(), all_nodes.len());
+        log::info!("Selected {} out of {} hosts. Building node configurations...", selected_nodes.len(), all_nodes.len());
     }
 
     hive.build_selected(selected_nodes).await.unwrap();
 
-    println!("Success!");
+    log::info!("Success!");
 }

src/command/introspect.rs

@@ -2,11 +2,10 @@ 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")
+    SubCommand::with_name("introspect")
         .about("Evaluate expressions using the complete configuration.")
         .long_about(r#"Your expression should take an attribute set with keys `pkgs`, `lib` and `nodes` (like a NixOS module) and return a JSON-serializable value.
 
@@ -22,22 +21,13 @@ For example, to retrieve the configuration of one node, you may write something
             .short("E")
             .help("The Nix expression")
             .takes_value(true))
-        .arg(Arg::with_name("config")
-            .short("f")
-            .long("config")
-            .help("Path to a Hive expression")
-            .default_value("hive.nix")
-            .required(true))
-        ;
-
-    util::register_common_args(command)
 }
 
 pub async fn run(_global_args: &ArgMatches<'_>, local_args: &ArgMatches<'_>) {
-    let mut hive = Hive::from_args(local_args).unwrap();
+    let mut hive = util::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.");
+        log::error!("Either an expression (-E) xor a .nix file containing an expression should be specified, not both.");
         quit::with_code(1);
     }
 

src/main.rs

@@ -1,4 +1,5 @@
-use clap::{App, AppSettings};
+use std::env;
+use clap::{App, AppSettings, Arg};
 
 mod nix;
 mod command;
@@ -29,22 +30,60 @@ macro_rules! bind_command {
 
 #[tokio::main(flavor = "multi_thread")]
 async fn main() {
+    init_logging();
+
     let mut app = App::new("Colmena")
         .version("0.1.0")
         .author("Zhaofeng Li <hello@zhaofeng.li>")
         .about("NixOS deployment tool")
         .global_setting(AppSettings::ColoredHelp)
-        .setting(AppSettings::ArgRequiredElseHelp);
+        .setting(AppSettings::ArgRequiredElseHelp)
+        .arg(Arg::with_name("config")
+            .short("f")
+            .long("config")
+            .help("Path to a Hive expression")
+
+            // The default value is a lie (sort of)!
+            //
+            // The default behavior is to search upwards from the
+            // current working directory for a file named "hive.nix".
+            // This behavior is disabled if --config/-f is explicitly
+            // supplied by the user (occurrences_of > 0).
+            .default_value("hive.nix")
+            .long_help(r#"If this argument is not specified, Colmena will search upwards from the current working directory for a file named "hive.nix". This behavior is disabled if --config/-f is given explicitly.
+
+For a sample configuration, see <https://github.com/zhaofengli/colmena>.
+"#)
+            .global(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")
+            .global(true)
+            .takes_value(false));
 
     bind_command!(apply, app);
     bind_command!(apply_local, app);
     bind_command!(build, app);
     bind_command!(introspect, app);
 
-    let matches = app.get_matches();
+    let matches = app.clone().get_matches();
 
     command!(apply, matches);
     command!("apply-local", apply_local, matches);
     command!(build, matches);
     command!(introspect, matches);
+
+    app.print_long_help().unwrap();
+}
+
+fn init_logging() {
+    if env::var("RUST_LOG").is_err() {
+        // HACK
+        env::set_var("RUST_LOG", "info")
+    }
+    env_logger::builder()
+        .format_timestamp(None)
+        .format_module_path(false)
+        .init();
 }

src/nix/host.rs

@@ -187,7 +187,7 @@ impl SSH {
                 progress.set_message(trimmed);
                 progress.inc(0);
             } else {
-                println!("{} | {}", style(&self.friendly_name).cyan(), trimmed);
+                eprintln!("{} | {}", style(&self.friendly_name).cyan(), trimmed);
             }
             self.logs.push(line);
         }

src/nix/mod.rs

@@ -6,7 +6,6 @@ use std::collections::HashMap;
 use std::fs;
 
 use async_trait::async_trait;
-use clap::ArgMatches;
 use indicatif::ProgressBar;
 use serde::de::DeserializeOwned;
 use serde::{Serialize, Deserialize};
@@ -72,17 +71,8 @@ impl Hive {
         })
     }
 
-    pub fn from_args(args: &ArgMatches<'_>) -> NixResult<Self> {
+    pub fn show_trace(&mut self, value: bool) {
-        let path = args.value_of("config").expect("The config arg should exist").to_owned();
+        self.show_trace = value;
-        let path = canonicalize_path(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
@@ -443,12 +433,3 @@ impl DeploymentTask {
         }
     }
 }
-
-fn canonicalize_path(path: String) -> PathBuf {
-    if !path.starts_with("/") {
-        format!("./{}", path).into()
-    } else {
-        path.into()
-    }
-}
-

src/util.rs

@@ -1,15 +1,89 @@
 use std::collections::HashMap;
+use std::path::PathBuf;
+use std::fs;
 
-use clap::{Arg, App};
+use clap::{App, Arg, ArgMatches};
 use glob::Pattern as GlobPattern;
 
-use super::nix::DeploymentConfig;
+use super::nix::{DeploymentConfig, Hive, NixResult};
 
 enum NodeFilter {
     NameFilter(GlobPattern),
     TagFilter(GlobPattern),
 }
 
+pub fn hive_from_args(args: &ArgMatches<'_>) -> NixResult<Hive> {
+    let path = match args.occurrences_of("config") {
+        0 => {
+            // traverse upwards until we find hive.nix
+            let mut cur = std::env::current_dir()?;
+            let mut hive_path = None;
+
+            loop {
+                let mut listing = match fs::read_dir(&cur) {
+                    Ok(listing) => listing,
+                    Err(e) => {
+                        // This can very likely fail in shared environments
+                        // where users aren't able to list /home. It's not
+                        // unexpected.
+                        //
+                        // It may not be immediately obvious to the user that
+                        // we are traversing upwards to find hive.nix.
+                        log::warn!("Could not traverse up ({:?}) to find hive.nix: {}", cur, e);
+                        break;
+                    },
+                };
+
+                let found = listing.find_map(|rdirent| {
+                    match rdirent {
+                        Err(e) => Some(Err(e)),
+                        Ok(f) => {
+                            if f.file_name() == "hive.nix" {
+                                Some(Ok(f))
+                            } else {
+                                None
+                            }
+                        }
+                    }
+                });
+
+                if let Some(rdirent) = found {
+                    let dirent = rdirent?;
+                    hive_path = Some(dirent.path());
+                    break;
+                }
+
+                match cur.parent() {
+                    Some(parent) => {
+                        cur = parent.to_owned();
+                    }
+                    None => {
+                        break;
+                    }
+                }
+            }
+
+            if hive_path.is_none() {
+                log::error!("Could not find `hive.nix` in {:?} or any parent directory", std::env::current_dir()?);
+            }
+
+            hive_path.unwrap()
+        }
+        _ => {
+            let path = args.value_of("config").expect("The config arg should exist").to_owned();
+            canonicalize_cli_path(path)
+        }
+    };
+
+    let mut hive = Hive::new(path)?;
+
+    if args.is_present("show-trace") {
+        hive.show_trace(true);
+    }
+
+    Ok(hive)
+}
+
 pub fn filter_nodes(nodes: &HashMap<String, DeploymentConfig>, filter: &str) -> Vec<String> {
     let filters: Vec<NodeFilter> = filter.split(",").map(|pattern| {
         use NodeFilter::*;
@@ -48,24 +122,7 @@ pub fn filter_nodes(nodes: &HashMap<String, DeploymentConfig>, filter: &str) ->
     }
 }
 
-pub fn register_common_args<'a, 'b>(command: App<'a, 'b>) -> App<'a, 'b> {
-    command
-        .arg(Arg::with_name("config")
-            .short("f")
-            .long("config")
-            .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")
@@ -79,3 +136,11 @@ Valid examples:
 - @a-tag,@tags-can-have-*"#)
             .takes_value(true))
 }
+
+fn canonicalize_cli_path(path: String) -> PathBuf {
+    if !path.starts_with("/") {
+        format!("./{}", path).into()
+    } else {
+        path.into()
+    }
+}