host: Add get_current_system_profile

src/error.rs

@@ -6,7 +6,7 @@ use std::process::ExitStatus;
 use snafu::Snafu;
 use validator::ValidationErrors;
 
-use crate::nix::{key, StorePath};
+use crate::nix::{key, StorePath, Profile};
 
 pub type ColmenaResult<T> = Result<T, ColmenaError>;
 
@@ -43,8 +43,8 @@ pub enum ColmenaError {
     #[snafu(display("Invalid NixOS system profile"))]
     InvalidProfile,
 
-    #[snafu(display("Unknown active profile: {:?}", store_path))]
-    ActiveProfileUnknown { store_path: StorePath },
+    #[snafu(display("Unknown active profile: {:?}", profile))]
+    ActiveProfileUnknown { profile: Profile },
 
     #[snafu(display("Could not determine current profile"))]
     FailedToGetCurrentProfile,

src/nix/deployment/mod.rs

@@ -538,13 +538,13 @@ impl Deployment {
 
                 let profile = host.get_main_system_profile().await?;
 
-                if profile.exists() {
+                if profile.as_store_path().exists() {
                     job.message("Remote profile known".to_string())?;
                 } else if arc_self.options.force_replace_unknown_profiles {
                     job.message("Warning: Remote profile is unknown, but unknown profiles are being ignored".to_string())?;
                 } else {
                     return Err(ColmenaError::ActiveProfileUnknown {
-                        store_path: profile,
+                        profile,
                     });
                 }
             }

src/nix/host/local.rs

@@ -92,7 +92,21 @@ impl Host for Local {
         result
     }
 
-    async fn get_main_system_profile(&mut self) -> ColmenaResult<StorePath> {
+    async fn get_current_system_profile(&mut self) -> ColmenaResult<Profile> {
+        let paths = Command::new("readlink")
+            .args(&["-e", CURRENT_PROFILE])
+            .capture_output()
+            .await?;
+
+        let path = paths.lines().into_iter().next()
+            .ok_or(ColmenaError::FailedToGetCurrentProfile)?
+            .to_string()
+            .try_into()?;
+
+        Ok(Profile::from_store_path_unchecked(path))
+    }
+
+    async fn get_main_system_profile(&mut self) -> ColmenaResult<Profile> {
         let paths = Command::new("sh")
             .args(&["-c", &format!("readlink -e {} || readlink -e {}", SYSTEM_PROFILE, CURRENT_PROFILE)])
             .capture_output()
@@ -103,7 +117,7 @@ impl Host for Local {
             .to_string()
             .try_into()?;
 
-        Ok(path)
+        Ok(Profile::from_store_path_unchecked(path))
     }
 
     fn set_job(&mut self, job: Option<JobHandle>) {

src/nix/host/mod.rs

@@ -111,12 +111,15 @@ pub trait Host: Send + Sync + std::fmt::Debug {
         Err(ColmenaError::Unsupported)
     }
 
+    /// Returns the current system profile on the host.
+    async fn get_current_system_profile(&mut self) -> ColmenaResult<Profile>;
+
     /// Returns the main system profile on the host.
     ///
     /// This may _not_ be the system profile that's currently activated!
     /// It will first try `/nix/var/nix/profiles/system`, falling back
     /// to `/run/current-system` if it doesn't exist.
-    async fn get_main_system_profile(&mut self) -> ColmenaResult<StorePath>;
+    async fn get_main_system_profile(&mut self) -> ColmenaResult<Profile>;
 
     /// Activates a system profile on the host, if it runs NixOS.
     ///

src/nix/host/ssh.rs

@@ -82,7 +82,20 @@ impl Host for Ssh {
         self.run_command(command).await
     }
 
-    async fn get_main_system_profile(&mut self) -> ColmenaResult<StorePath> {
+    async fn get_current_system_profile(&mut self) -> ColmenaResult<Profile> {
+        let paths = self.ssh(&["readlink", "-e", CURRENT_PROFILE])
+            .capture_output()
+            .await?;
+
+        let path = paths.lines().into_iter().next()
+            .ok_or(ColmenaError::FailedToGetCurrentProfile)?
+            .to_string()
+            .try_into()?;
+
+        Ok(Profile::from_store_path_unchecked(path))
+    }
+
+    async fn get_main_system_profile(&mut self) -> ColmenaResult<Profile> {
         let command = format!("\"readlink -e {} || readlink -e {}\"", SYSTEM_PROFILE, CURRENT_PROFILE);
 
         let paths = self.ssh(&["sh", "-c", &command])
@@ -94,7 +107,7 @@ impl Host for Ssh {
             .to_string()
             .try_into()?;
 
-        Ok(path)
+        Ok(Profile::from_store_path_unchecked(path))
     }
 
     async fn run_command(&mut self, command: &[&str]) -> ColmenaResult<()> {

src/nix/profile.rs

@@ -16,7 +16,7 @@ use super::{
 pub type ProfileDerivation = StoreDerivation<Profile>;
 
 /// A NixOS system profile.
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq, Eq)]
 pub struct Profile(StorePath);
 
 impl Profile {
@@ -77,7 +77,7 @@ impl Profile {
         Ok(())
     }
 
-    fn from_store_path_unchecked(path: StorePath) -> Self {
+    pub(super) fn from_store_path_unchecked(path: StorePath) -> Self {
         Self(path)
     }
 }

src/nix/store.rs

@@ -12,7 +12,7 @@ use crate::util::CommandExt;
 use super::Host;
 
 /// A Nix store path.
-#[derive(Debug, Clone, Serialize, Deserialize)]
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct StorePath(PathBuf);
 
 /// A store derivation (.drv) that will result in a T when built.