Merge pull request #52 from wobcom/fix/fairy/nix-not-installed

don't run fairy if nix isn't installed

fairy/Cargo.toml

@@ -17,4 +17,8 @@ serde_yaml = "0.9.25"
 tokio = { version = "1.32.0", features = ["rt", "macros", "process"] }
 tokio-util = { version = "0.7.9", features = ["codec"] }
 uuid = { version = "1.4.1", features = ["serde"] }
-rocket = { version="0.5.0", features = ["json", "secrets"] } 
+rocket = { version="0.5.0", features = ["json", "secrets"] }
+which = "6.0.1"
+
+[features]
+nixless-test-mode = []

fairy/src/main.rs

@@ -1,16 +1,17 @@
+use std::process::{exit, Stdio};
+use std::sync::Arc;
+
 use anyhow::anyhow;
 use futures_util::{Sink, StreamExt, TryStreamExt};
 use hyper::{Body, Client, Method, Request};
-use serde::de::DeserializeOwned;
+use rocket::figment::{Figment, Profile};
+use rocket::figment::providers::{Env, Format, Toml};
 use serde::{Deserialize, Serialize};
-use std::process::Stdio;
-use std::sync::Arc;
+use serde::de::DeserializeOwned;
 use tokio::process::Command;
 use tokio_util::codec::{FramedRead, LinesCodec};
 use uuid::Uuid;
-
-use rocket::figment::providers::{Env, Format, Toml};
-use rocket::figment::{Figment, Profile};
+use which::which;
 
 #[derive(Deserialize)]
 pub(crate) struct AppConfig {
@@ -20,11 +21,23 @@ pub(crate) struct AppConfig {
     pub(crate) features: Vec<String>,
 }
 
+const CODE_NIX_NOT_INSTALLED: i32 = 1;
+
+fn ensure_nix() {
+    if which("nix").is_err() {
+        log::error!("\"nix\" binary not found. Please install nix or run on a nix-os host.");
+        exit(CODE_NIX_NOT_INSTALLED);
+    }
+}
+
 fn main() -> anyhow::Result<()> {
     env_logger::builder()
         .filter_level(log::LevelFilter::Debug)
         .init();
 
+    #[cfg(not(feature = "nixless-test-mode"))]
+    ensure_nix();
+
     log::info!("Fairy starting up.");
 
     // Took from rocket source code and added .split("__") to be able to add keys in nested structures.
@@ -170,13 +183,18 @@ async fn try_run_task(cfg: Arc<AppConfig>, task: &Task) -> anyhow::Result<()> {
 }
 
 async fn run_task(cfg: Arc<AppConfig>, task: Task) {
+    #[cfg(not(feature = "nixless-test-mode"))]
     let result = match try_run_task(cfg.clone(), &task).await {
-        Err(e) => {
-            log::info!("task failed: {} {} {:?}", task.id, task.display_name, e);
-            TaskResult::Error
-        }
-        Ok(_) => TaskResult::Success,
-    };
+            Err(e) => {
+                log::info!("task failed: {} {} {:?}", task.id, task.display_name, e);
+                TaskResult::Error
+            }
+            Ok(_) => TaskResult::Success,
+        };
+
+    #[cfg(feature = "nixless-test-mode")]
+    let result = TaskResult::Success;
+
     tokio::time::sleep(std::time::Duration::from_secs(1)).await;
     let _ = api::<_, ()>(
         &cfg,