netrc: w/ dnixd, don't update netrc, require it to be right path

magic-nix-cache/src/flakehub.rs

@@ -1,5 +1,5 @@
 use crate::env::Environment;
-use crate::error::{Error, Result};
+use crate::error::{self, Error, Result};
 use anyhow::Context;
 use attic::cache::CacheName;
 use attic::nix_store::{NixStore, StorePath};
@@ -9,6 +9,7 @@ use attic_client::{
     config::ServerConfig,
     push::{PushConfig, Pusher},
 };
+
 use reqwest::header::HeaderValue;
 use reqwest::Url;
 use serde::Deserialize;
@@ -35,7 +36,16 @@ pub async fn init_cache(
     flakehub_cache_server: &Url,
     flakehub_flake_name: Option<String>,
     store: Arc<NixStore>,
+    using_dnixd: bool,
 ) -> Result<State> {
+    if using_dnixd {
+        let dnixd_state_dir: &Path = Path::new(&crate::DETERMINATE_STATE_DIR);
+        let expected_netrc_path = dnixd_state_dir.join("netrc");
+        if flakehub_api_server_netrc != expected_netrc_path {
+            let err = format!("flakehub-api-server-netrc was ({}), expected ({}) since determinate-nixd is available", flakehub_api_server_netrc.display(), expected_netrc_path.display());
+            return Err(error::Error::Config(err));
+        }
+    }
     // Parse netrc to get the credentials for api.flakehub.com.
     let netrc = {
         let mut netrc_file = File::open(flakehub_api_server_netrc).await.map_err(|e| {
@@ -89,6 +99,7 @@ pub async fn init_cache(
         ))
     })?;
 
+    if !using_dnixd {
         // Append an entry for the FlakeHub cache server to netrc.
         if !netrc
             .machines
@@ -125,6 +136,7 @@ pub async fn init_cache(
                     ))
                 })?;
         }
+    }
 
     let server_config = ServerConfig {
         endpoint: flakehub_cache_server.to_string(),

magic-nix-cache/src/main.rs

@@ -233,6 +233,7 @@ async fn main_cli() -> Result<()> {
             &flakehub_cache_server,
             flakehub_flake_name,
             store.clone(),
+            dnixd_available,
         )
         .await
         {