binary-cache/pkgs/tvix/01-remote-path-info-nar-bridge.patch

diff --git a/tvix/castore/src/composition.rs b/tvix/castore/src/composition.rs
index daa8a5008..18a767284 100644
--- a/tvix/castore/src/composition.rs
+++ b/tvix/castore/src/composition.rs
@@ -454,11 +454,4 @@ impl Composition {
         *entry = Box::new(new_val);
         ret
     }
-
-    pub fn context(&self) -> CompositionContext {
-        CompositionContext {
-            stack: vec![],
-            composition: Some(self),
-        }
-    }
 }
diff --git a/tvix/cli/src/lib.rs b/tvix/cli/src/lib.rs
index 070e88e35..800ffb4e0 100644
--- a/tvix/cli/src/lib.rs
+++ b/tvix/cli/src/lib.rs
@@ -60,7 +60,7 @@ pub fn init_io_handle(tokio_runtime: &tokio::runtime::Runtime, args: &Args) -> R
     Rc::new(TvixStoreIO::new(
         blob_service.clone(),
         directory_service.clone(),
-        path_info_service,
+        path_info_service.into(),
         nar_calculation_service.into(),
         build_service.into(),
         tokio_runtime.handle().clone(),
diff --git a/tvix/glue/benches/eval.rs b/tvix/glue/benches/eval.rs
index ee3d554dc..55f37f2d5 100644
--- a/tvix/glue/benches/eval.rs
+++ b/tvix/glue/benches/eval.rs
@@ -34,7 +34,7 @@ fn interpret(code: &str) {
     let tvix_store_io = Rc::new(TvixStoreIO::new(
         blob_service,
         directory_service,
-        path_info_service,
+        path_info_service.into(),
         nar_calculation_service.into(),
         Arc::<DummyBuildService>::default(),
         TOKIO_RUNTIME.handle().clone(),
diff --git a/tvix/glue/src/builtins/mod.rs b/tvix/glue/src/builtins/mod.rs
index e1d1c9c84..e1c20e461 100644
--- a/tvix/glue/src/builtins/mod.rs
+++ b/tvix/glue/src/builtins/mod.rs
@@ -80,7 +80,7 @@ mod tests {
         let io = Rc::new(TvixStoreIO::new(
             blob_service,
             directory_service,
-            path_info_service,
+            path_info_service.into(),
             nar_calculation_service.into(),
             Arc::<DummyBuildService>::default(),
             runtime.handle().clone(),
diff --git a/tvix/glue/src/tests/mod.rs b/tvix/glue/src/tests/mod.rs
index e9f21c329..142ae1a07 100644
--- a/tvix/glue/src/tests/mod.rs
+++ b/tvix/glue/src/tests/mod.rs
@@ -41,7 +41,7 @@ fn eval_test(code_path: PathBuf, expect_success: bool) {
     let tvix_store_io = Rc::new(TvixStoreIO::new(
         blob_service,
         directory_service,
-        path_info_service,
+        path_info_service.into(),
         nar_calculation_service.into(),
         Arc::new(DummyBuildService::default()),
         tokio_runtime.handle().clone(),
diff --git a/tvix/glue/src/tvix_store_io.rs b/tvix/glue/src/tvix_store_io.rs
index cfc037e8d..e8c09af0e 100644
--- a/tvix/glue/src/tvix_store_io.rs
+++ b/tvix/glue/src/tvix_store_io.rs
@@ -648,7 +648,7 @@ mod tests {
         let io = Rc::new(TvixStoreIO::new(
             blob_service,
             directory_service,
-            path_info_service,
+            path_info_service.into(),
             nar_calculation_service.into(),
             Arc::<DummyBuildService>::default(),
             tokio_runtime.handle().clone(),
diff --git a/tvix/nar-bridge/src/bin/nar-bridge.rs b/tvix/nar-bridge/src/bin/nar-bridge.rs
index 1e4223775..b24f155a7 100644
--- a/tvix/nar-bridge/src/bin/nar-bridge.rs
+++ b/tvix/nar-bridge/src/bin/nar-bridge.rs
@@ -1,6 +1,7 @@
 use clap::Parser;
 use nar_bridge::AppState;
 use tracing::info;
+use tvix_store::pathinfoservice::{CachePathInfoService, PathInfoService};
 
 /// Expose the Nix HTTP Binary Cache protocol for a tvix-store.
 #[derive(Parser)]
@@ -15,6 +16,12 @@ struct Cli {
     #[arg(long, env, default_value = "grpc+http://[::1]:8000")]
     path_info_service_addr: String,
 
+    /// URL to a PathInfoService that's considered "remote".
+    /// If set, the other one is considered "local", and a "cache" for the
+    /// "remote" one.
+    #[arg(long, env)]
+    remote_path_info_service_addr: Option<String>,
+
     /// The priority to announce at the `nix-cache-info` endpoint.
     /// A lower number means it's *more preferred.
     #[arg(long, env, default_value_t = 39)]
@@ -55,7 +62,25 @@ async fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
         )
         .await?;
 
-    let state = AppState::new(blob_service, directory_service, path_info_service);
+    // if remote_path_info_service_addr has been specified,
+    // update path_info_service to point to a cache combining the two.
+    let path_info_service = if let Some(addr) = cli.remote_path_info_service_addr {
+        let remote_path_info_service = tvix_store::pathinfoservice::from_addr(
+            &addr,
+            blob_service.clone(),
+            directory_service.clone(),
+        )
+        .await?;
+
+        let path_info_service =
+            CachePathInfoService::new(path_info_service, remote_path_info_service);
+
+        Box::new(path_info_service) as Box<dyn PathInfoService>
+    } else {
+        path_info_service
+    };
+
+    let state = AppState::new(blob_service, directory_service, path_info_service.into());
 
     let app = nar_bridge::gen_router(cli.priority).with_state(state);
 
diff --git a/tvix/store/src/bin/tvix-store.rs b/tvix/store/src/bin/tvix-store.rs
index 99323d2a5..82c73f8f4 100644
--- a/tvix/store/src/bin/tvix-store.rs
+++ b/tvix/store/src/bin/tvix-store.rs
@@ -16,6 +16,7 @@ use tracing::{info, info_span, instrument, Level, Span};
 use tracing_indicatif::span_ext::IndicatifSpanExt as _;
 use tvix_castore::import::fs::ingest_path;
 use tvix_store::nar::NarCalculationService;
+use tvix_store::pathinfoservice::CachePathInfoService;
 use tvix_store::proto::NarInfo;
 use tvix_store::proto::PathInfo;
 
@@ -209,38 +210,31 @@ async fn run_cli(cli: Cli) -> Result<(), Box<dyn std::error::Error + Send + Sync
             remote_path_info_service_addr,
         } => {
             // initialize stores
-            let mut configs = tvix_store::utils::addrs_to_configs(
-                blob_service_addr,
-                directory_service_addr,
-                path_info_service_addr,
-            )?;
+            let (blob_service, directory_service, path_info_service, nar_calculation_service) =
+                tvix_store::utils::construct_services(
+                    blob_service_addr,
+                    directory_service_addr,
+                    path_info_service_addr,
+                )
+                .await?;
 
             // if remote_path_info_service_addr has been specified,
             // update path_info_service to point to a cache combining the two.
-            if let Some(addr) = remote_path_info_service_addr {
-                use tvix_store::composition::{with_registry, DeserializeWithRegistry, REG};
-                use tvix_store::pathinfoservice::CachePathInfoServiceConfig;
-
-                let remote_url = url::Url::parse(&addr)?;
-                let remote_config = with_registry(&REG, || remote_url.try_into())?;
-
-                let local = configs.pathinfoservices.insert(
-                    "default".into(),
-                    DeserializeWithRegistry(Box::new(CachePathInfoServiceConfig {
-                        near: "local".into(),
-                        far: "remote".into(),
-                    })),
-                );
-                configs
-                    .pathinfoservices
-                    .insert("local".into(), local.unwrap());
-                configs
-                    .pathinfoservices
-                    .insert("remote".into(), remote_config);
-            }
+            let path_info_service = if let Some(addr) = remote_path_info_service_addr {
+                let remote_path_info_service = tvix_store::pathinfoservice::from_addr(
+                    &addr,
+                    blob_service.clone(),
+                    directory_service.clone(),
+                )
+                .await?;
 
-            let (blob_service, directory_service, path_info_service, nar_calculation_service) =
-                tvix_store::utils::construct_services_from_configs(configs).await?;
+                let path_info_service =
+                    CachePathInfoService::new(path_info_service, remote_path_info_service);
+
+                Box::new(path_info_service) as Box<dyn PathInfoService>
+            } else {
+                path_info_service
+            };
 
             let mut server = Server::builder().layer(
                 ServiceBuilder::new()
@@ -263,7 +257,7 @@ async fn run_cli(cli: Cli) -> Result<(), Box<dyn std::error::Error + Send + Sync
                     GRPCDirectoryServiceWrapper::new(directory_service),
                 ))
                 .add_service(PathInfoServiceServer::new(GRPCPathInfoServiceWrapper::new(
-                    path_info_service,
+                    Arc::from(path_info_service),
                     nar_calculation_service,
                 )));
 
@@ -308,7 +302,8 @@ async fn run_cli(cli: Cli) -> Result<(), Box<dyn std::error::Error + Send + Sync
                 )
                 .await?;
 
-            // Arc NarCalculationService, as we clone it .
+            // Arc PathInfoService and NarCalculationService, as we clone it .
+            let path_info_service: Arc<dyn PathInfoService> = path_info_service.into();
             let nar_calculation_service: Arc<dyn NarCalculationService> =
                 nar_calculation_service.into();
 
@@ -370,6 +365,9 @@ async fn run_cli(cli: Cli) -> Result<(), Box<dyn std::error::Error + Send + Sync
             let reference_graph: ReferenceGraph<'_> =
                 serde_json::from_slice(reference_graph_json.as_slice())?;
 
+            // Arc the PathInfoService, as we clone it .
+            let path_info_service: Arc<dyn PathInfoService> = path_info_service.into();
+
             let lookups_span = info_span!(
                 "lookup pathinfos",
                 "indicatif.pb_show" = tracing::field::Empty
@@ -477,7 +475,7 @@ async fn run_cli(cli: Cli) -> Result<(), Box<dyn std::error::Error + Send + Sync
                 let fs = make_fs(
                     blob_service,
                     directory_service,
-                    path_info_service,
+                    Arc::from(path_info_service),
                     list_root,
                     show_xattr,
                 );
@@ -525,7 +523,7 @@ async fn run_cli(cli: Cli) -> Result<(), Box<dyn std::error::Error + Send + Sync
                 let fs = make_fs(
                     blob_service,
                     directory_service,
-                    path_info_service,
+                    Arc::from(path_info_service),
                     list_root,
                     show_xattr,
                 );
diff --git a/tvix/store/src/composition.rs b/tvix/store/src/composition.rs
deleted file mode 100644
index a32f22cf7..000000000
--- a/tvix/store/src/composition.rs
+++ /dev/null
@@ -1,22 +0,0 @@
-use lazy_static::lazy_static;
-
-pub use tvix_castore::composition::*;
-
-lazy_static! {
-    /// The provided registry of tvix_store, which has all the builtin
-    /// tvix_castore (BlobStore/DirectoryStore) and tvix_store
-    /// (PathInfoService) implementations.
-    pub static ref REG: Registry = {
-        let mut reg = Default::default();
-        add_default_services(&mut reg);
-        reg
-    };
-}
-
-/// Register the builtin services of tvix_castore and tvix_store with the given
-/// registry. This is useful for creating your own registry with the builtin
-/// types _and_ extra third party types.
-pub fn add_default_services(reg: &mut Registry) {
-    tvix_castore::composition::add_default_services(reg);
-    crate::pathinfoservice::register_pathinfo_services(reg);
-}
diff --git a/tvix/store/src/lib.rs b/tvix/store/src/lib.rs
index 81a77cd97..8c32aaf88 100644
--- a/tvix/store/src/lib.rs
+++ b/tvix/store/src/lib.rs
@@ -1,4 +1,3 @@
-pub mod composition;
 pub mod import;
 pub mod nar;
 pub mod pathinfoservice;
diff --git a/tvix/store/src/pathinfoservice/bigtable.rs b/tvix/store/src/pathinfoservice/bigtable.rs
index 15128986f..26d07689d 100644
--- a/tvix/store/src/pathinfoservice/bigtable.rs
+++ b/tvix/store/src/pathinfoservice/bigtable.rs
@@ -10,17 +10,15 @@ use nix_compat::nixbase32;
 use prost::Message;
 use serde::{Deserialize, Serialize};
 use serde_with::{serde_as, DurationSeconds};
-use std::sync::Arc;
 use tonic::async_trait;
 use tracing::{instrument, trace};
-use tvix_castore::composition::{CompositionContext, ServiceBuilder};
 use tvix_castore::Error;
 
 /// There should not be more than 10 MiB in a single cell.
 /// https://cloud.google.com/bigtable/docs/schema-design#cells
 const CELL_SIZE_LIMIT: u64 = 10 * 1024 * 1024;
 
-/// Provides a [PathInfoService] implementation using
+/// Provides a [DirectoryService] implementation using
 /// [Bigtable](https://cloud.google.com/bigtable/docs/)
 /// as an underlying K/V store.
 ///
@@ -46,6 +44,57 @@ pub struct BigtablePathInfoService {
     emulator: std::sync::Arc<(tempfile::TempDir, async_process::Child)>,
 }
 
+/// Represents configuration of [BigtablePathInfoService].
+/// This currently conflates both connect parameters and data model/client
+/// behaviour parameters.
+#[serde_as]
+#[derive(Clone, Debug, PartialEq, Deserialize, Serialize)]
+pub struct BigtableParameters {
+    project_id: String,
+    instance_name: String,
+    #[serde(default)]
+    is_read_only: bool,
+    #[serde(default = "default_channel_size")]
+    channel_size: usize,
+
+    #[serde_as(as = "Option<DurationSeconds<String>>")]
+    #[serde(default = "default_timeout")]
+    timeout: Option<std::time::Duration>,
+    table_name: String,
+    family_name: String,
+
+    #[serde(default = "default_app_profile_id")]
+    app_profile_id: String,
+}
+
+impl BigtableParameters {
+    #[cfg(test)]
+    pub fn default_for_tests() -> Self {
+        Self {
+            project_id: "project-1".into(),
+            instance_name: "instance-1".into(),
+            is_read_only: false,
+            channel_size: default_channel_size(),
+            timeout: default_timeout(),
+            table_name: "table-1".into(),
+            family_name: "cf1".into(),
+            app_profile_id: default_app_profile_id(),
+        }
+    }
+}
+
+fn default_app_profile_id() -> String {
+    "default".to_owned()
+}
+
+fn default_channel_size() -> usize {
+    4
+}
+
+fn default_timeout() -> Option<std::time::Duration> {
+    Some(std::time::Duration::from_secs(4))
+}
+
 impl BigtablePathInfoService {
     #[cfg(not(test))]
     pub async fn connect(params: BigtableParameters) -> Result<Self, bigtable::Error> {
@@ -363,88 +412,3 @@ impl PathInfoService for BigtablePathInfoService {
         Box::pin(stream)
     }
 }
-
-/// Represents configuration of [BigtablePathInfoService].
-/// This currently conflates both connect parameters and data model/client
-/// behaviour parameters.
-#[serde_as]
-#[derive(Clone, Debug, PartialEq, Deserialize, Serialize)]
-pub struct BigtableParameters {
-    project_id: String,
-    instance_name: String,
-    #[serde(default)]
-    is_read_only: bool,
-    #[serde(default = "default_channel_size")]
-    channel_size: usize,
-
-    #[serde_as(as = "Option<DurationSeconds<String>>")]
-    #[serde(default = "default_timeout")]
-    timeout: Option<std::time::Duration>,
-    table_name: String,
-    family_name: String,
-
-    #[serde(default = "default_app_profile_id")]
-    app_profile_id: String,
-}
-
-impl BigtableParameters {
-    #[cfg(test)]
-    pub fn default_for_tests() -> Self {
-        Self {
-            project_id: "project-1".into(),
-            instance_name: "instance-1".into(),
-            is_read_only: false,
-            channel_size: default_channel_size(),
-            timeout: default_timeout(),
-            table_name: "table-1".into(),
-            family_name: "cf1".into(),
-            app_profile_id: default_app_profile_id(),
-        }
-    }
-}
-
-fn default_app_profile_id() -> String {
-    "default".to_owned()
-}
-
-fn default_channel_size() -> usize {
-    4
-}
-
-fn default_timeout() -> Option<std::time::Duration> {
-    Some(std::time::Duration::from_secs(4))
-}
-
-#[async_trait]
-impl ServiceBuilder for BigtableParameters {
-    type Output = dyn PathInfoService;
-    async fn build<'a>(
-        &'a self,
-        _instance_name: &str,
-        _context: &CompositionContext,
-    ) -> Result<Arc<dyn PathInfoService>, Box<dyn std::error::Error + Send + Sync>> {
-        Ok(Arc::new(
-            BigtablePathInfoService::connect(self.clone()).await?,
-        ))
-    }
-}
-
-impl TryFrom<url::Url> for BigtableParameters {
-    type Error = Box<dyn std::error::Error + Send + Sync>;
-    fn try_from(mut url: url::Url) -> Result<Self, Self::Error> {
-        // parse the instance name from the hostname.
-        let instance_name = url
-            .host_str()
-            .ok_or_else(|| Error::StorageError("instance name missing".into()))?
-            .to_string();
-
-        // … but add it to the query string now, so we just need to parse that.
-        url.query_pairs_mut()
-            .append_pair("instance_name", &instance_name);
-
-        let params: BigtableParameters = serde_qs::from_str(url.query().unwrap_or_default())
-            .map_err(|e| Error::InvalidRequest(format!("failed to parse parameters: {}", e)))?;
-
-        Ok(params)
-    }
-}
diff --git a/tvix/store/src/pathinfoservice/combinators.rs b/tvix/store/src/pathinfoservice/combinators.rs
index bb5595f72..664144ef4 100644
--- a/tvix/store/src/pathinfoservice/combinators.rs
+++ b/tvix/store/src/pathinfoservice/combinators.rs
@@ -1,11 +1,8 @@
-use std::sync::Arc;
-
 use crate::proto::PathInfo;
 use futures::stream::BoxStream;
 use nix_compat::nixbase32;
 use tonic::async_trait;
 use tracing::{debug, instrument};
-use tvix_castore::composition::{CompositionContext, ServiceBuilder};
 use tvix_castore::Error;
 
 use super::PathInfoService;
@@ -64,41 +61,6 @@ where
     }
 }
 
-#[derive(serde::Deserialize)]
-pub struct CacheConfig {
-    pub near: String,
-    pub far: String,
-}
-
-impl TryFrom<url::Url> for CacheConfig {
-    type Error = Box<dyn std::error::Error + Send + Sync>;
-    fn try_from(_url: url::Url) -> Result<Self, Self::Error> {
-        Err(Error::StorageError(
-            "Instantiating a CombinedPathInfoService from a url is not supported".into(),
-        )
-        .into())
-    }
-}
-
-#[async_trait]
-impl ServiceBuilder for CacheConfig {
-    type Output = dyn PathInfoService;
-    async fn build<'a>(
-        &'a self,
-        _instance_name: &str,
-        context: &CompositionContext,
-    ) -> Result<Arc<dyn PathInfoService>, Box<dyn std::error::Error + Send + Sync + 'static>> {
-        let (near, far) = futures::join!(
-            context.resolve(self.near.clone()),
-            context.resolve(self.far.clone())
-        );
-        Ok(Arc::new(Cache {
-            near: near?,
-            far: far?,
-        }))
-    }
-}
-
 #[cfg(test)]
 mod test {
     use std::num::NonZeroUsize;
diff --git a/tvix/store/src/pathinfoservice/from_addr.rs b/tvix/store/src/pathinfoservice/from_addr.rs
index 5635c226c..9173d25d0 100644
--- a/tvix/store/src/pathinfoservice/from_addr.rs
+++ b/tvix/store/src/pathinfoservice/from_addr.rs
@@ -1,10 +1,13 @@
-use super::PathInfoService;
+use crate::proto::path_info_service_client::PathInfoServiceClient;
 
-use crate::composition::{
-    with_registry, CompositionContext, DeserializeWithRegistry, ServiceBuilder, REG,
+use super::{
+    GRPCPathInfoService, MemoryPathInfoService, NixHTTPPathInfoService, PathInfoService,
+    SledPathInfoService,
 };
+
+use nix_compat::narinfo;
 use std::sync::Arc;
-use tvix_castore::Error;
+use tvix_castore::{blobservice::BlobService, directoryservice::DirectoryService, Error};
 use url::Url;
 
 /// Constructs a new instance of a [PathInfoService] from an URI.
@@ -31,21 +34,113 @@ use url::Url;
 /// these also need to be passed in.
 pub async fn from_addr(
     uri: &str,
-    context: Option<&CompositionContext<'_>>,
-) -> Result<Arc<dyn PathInfoService>, Box<dyn std::error::Error + Send + Sync>> {
+    blob_service: Arc<dyn BlobService>,
+    directory_service: Arc<dyn DirectoryService>,
+) -> Result<Box<dyn PathInfoService>, Error> {
     #[allow(unused_mut)]
     let mut url =
         Url::parse(uri).map_err(|e| Error::StorageError(format!("unable to parse url: {}", e)))?;
 
-    let path_info_service_config = with_registry(&REG, || {
-        <DeserializeWithRegistry<Box<dyn ServiceBuilder<Output = dyn PathInfoService>>>>::try_from(
-            url,
-        )
-    })?
-    .0;
-    let path_info_service = path_info_service_config
-        .build("anonymous", context.unwrap_or(&CompositionContext::blank()))
-        .await?;
+    let path_info_service: Box<dyn PathInfoService> = match url.scheme() {
+        "memory" => {
+            // memory doesn't support host or path in the URL.
+            if url.has_host() || !url.path().is_empty() {
+                return Err(Error::StorageError("invalid url".to_string()));
+            }
+            Box::<MemoryPathInfoService>::default()
+        }
+        "sled" => {
+            // sled doesn't support host, and a path can be provided (otherwise
+            // it'll live in memory only).
+            if url.has_host() {
+                return Err(Error::StorageError("no host allowed".to_string()));
+            }
+
+            if url.path() == "/" {
+                return Err(Error::StorageError(
+                    "cowardly refusing to open / with sled".to_string(),
+                ));
+            }
+
+            // TODO: expose other parameters as URL parameters?
+
+            Box::new(if url.path().is_empty() {
+                SledPathInfoService::new_temporary()
+                    .map_err(|e| Error::StorageError(e.to_string()))?
+            } else {
+                SledPathInfoService::new(url.path())
+                    .map_err(|e| Error::StorageError(e.to_string()))?
+            })
+        }
+        "nix+http" | "nix+https" => {
+            // Stringify the URL and remove the nix+ prefix.
+            // We can't use `url.set_scheme(rest)`, as it disallows
+            // setting something http(s) that previously wasn't.
+            let new_url = Url::parse(url.to_string().strip_prefix("nix+").unwrap()).unwrap();
+
+            let mut nix_http_path_info_service =
+                NixHTTPPathInfoService::new(new_url, blob_service, directory_service);
+
+            let pairs = &url.query_pairs();
+            for (k, v) in pairs.into_iter() {
+                if k == "trusted-public-keys" {
+                    let pubkey_strs: Vec<_> = v.split_ascii_whitespace().collect();
+
+                    let mut pubkeys: Vec<narinfo::PubKey> = Vec::with_capacity(pubkey_strs.len());
+                    for pubkey_str in pubkey_strs {
+                        pubkeys.push(narinfo::PubKey::parse(pubkey_str).map_err(|e| {
+                            Error::StorageError(format!("invalid public key: {e}"))
+                        })?);
+                    }
+
+                    nix_http_path_info_service.set_public_keys(pubkeys);
+                }
+            }
+
+            Box::new(nix_http_path_info_service)
+        }
+        scheme if scheme.starts_with("grpc+") => {
+            // schemes starting with grpc+ go to the GRPCPathInfoService.
+            //   That's normally grpc+unix for unix sockets, and grpc+http(s) for the HTTP counterparts.
+            // - In the case of unix sockets, there must be a path, but may not be a host.
+            // - In the case of non-unix sockets, there must be a host, but no path.
+            // Constructing the channel is handled by tvix_castore::channel::from_url.
+            Box::new(GRPCPathInfoService::from_client(
+                PathInfoServiceClient::with_interceptor(
+                    tvix_castore::tonic::channel_from_url(&url).await?,
+                    tvix_tracing::propagate::tonic::send_trace,
+                ),
+            ))
+        }
+        #[cfg(feature = "cloud")]
+        "bigtable" => {
+            use super::bigtable::BigtableParameters;
+            use super::BigtablePathInfoService;
+
+            // parse the instance name from the hostname.
+            let instance_name = url
+                .host_str()
+                .ok_or_else(|| Error::StorageError("instance name missing".into()))?
+                .to_string();
+
+            // … but add it to the query string now, so we just need to parse that.
+            url.query_pairs_mut()
+                .append_pair("instance_name", &instance_name);
+
+            let params: BigtableParameters = serde_qs::from_str(url.query().unwrap_or_default())
+                .map_err(|e| Error::InvalidRequest(format!("failed to parse parameters: {}", e)))?;
+
+            Box::new(
+                BigtablePathInfoService::connect(params)
+                    .await
+                    .map_err(|e| Error::StorageError(e.to_string()))?,
+            )
+        }
+        _ => Err(Error::StorageError(format!(
+            "unknown scheme: {}",
+            url.scheme()
+        )))?,
+    };
 
     Ok(path_info_service)
 }
@@ -53,12 +148,14 @@ pub async fn from_addr(
 #[cfg(test)]
 mod tests {
     use super::from_addr;
-    use crate::composition::{Composition, DeserializeWithRegistry, ServiceBuilder};
     use lazy_static::lazy_static;
     use rstest::rstest;
+    use std::sync::Arc;
     use tempfile::TempDir;
-    use tvix_castore::blobservice::{BlobService, MemoryBlobServiceConfig};
-    use tvix_castore::directoryservice::{DirectoryService, MemoryDirectoryServiceConfig};
+    use tvix_castore::{
+        blobservice::{BlobService, MemoryBlobService},
+        directoryservice::{DirectoryService, MemoryDirectoryService},
+    };
 
     lazy_static! {
         static ref TMPDIR_SLED_1: TempDir = TempDir::new().unwrap();
@@ -127,19 +224,11 @@ mod tests {
     )]
     #[tokio::test]
     async fn test_from_addr_tokio(#[case] uri_str: &str, #[case] exp_succeed: bool) {
-        let mut comp = Composition::default();
-        comp.extend(vec![(
-            "default".into(),
-            DeserializeWithRegistry(Box::new(MemoryBlobServiceConfig {})
-                as Box<dyn ServiceBuilder<Output = dyn BlobService>>),
-        )]);
-        comp.extend(vec![(
-            "default".into(),
-            DeserializeWithRegistry(Box::new(MemoryDirectoryServiceConfig {})
-                as Box<dyn ServiceBuilder<Output = dyn DirectoryService>>),
-        )]);
-
-        let resp = from_addr(uri_str, Some(&comp.context())).await;
+        let blob_service: Arc<dyn BlobService> = Arc::from(MemoryBlobService::default());
+        let directory_service: Arc<dyn DirectoryService> =
+            Arc::from(MemoryDirectoryService::default());
+
+        let resp = from_addr(uri_str, blob_service, directory_service).await;
 
         if exp_succeed {
             resp.expect("should succeed");
diff --git a/tvix/store/src/pathinfoservice/grpc.rs b/tvix/store/src/pathinfoservice/grpc.rs
index 2ac0e4330..bcee49aac 100644
--- a/tvix/store/src/pathinfoservice/grpc.rs
+++ b/tvix/store/src/pathinfoservice/grpc.rs
@@ -6,11 +6,9 @@ use crate::{
 use async_stream::try_stream;
 use futures::stream::BoxStream;
 use nix_compat::nixbase32;
-use std::sync::Arc;
 use tonic::{async_trait, Code};
 use tracing::{instrument, Span};
 use tracing_indicatif::span_ext::IndicatifSpanExt;
-use tvix_castore::composition::{CompositionContext, ServiceBuilder};
 use tvix_castore::{proto as castorepb, Error};
 
 /// Connects to a (remote) tvix-store PathInfoService over gRPC.
@@ -151,40 +149,6 @@ where
     }
 }
 
-#[derive(serde::Deserialize, Debug)]
-#[serde(deny_unknown_fields)]
-pub struct GRPCPathInfoServiceConfig {
-    url: String,
-}
-
-impl TryFrom<url::Url> for GRPCPathInfoServiceConfig {
-    type Error = Box<dyn std::error::Error + Send + Sync>;
-    fn try_from(url: url::Url) -> Result<Self, Self::Error> {
-        //   normally grpc+unix for unix sockets, and grpc+http(s) for the HTTP counterparts.
-        // - In the case of unix sockets, there must be a path, but may not be a host.
-        // - In the case of non-unix sockets, there must be a host, but no path.
-        // Constructing the channel is handled by tvix_castore::channel::from_url.
-        Ok(GRPCPathInfoServiceConfig {
-            url: url.to_string(),
-        })
-    }
-}
-
-#[async_trait]
-impl ServiceBuilder for GRPCPathInfoServiceConfig {
-    type Output = dyn PathInfoService;
-    async fn build<'a>(
-        &'a self,
-        _instance_name: &str,
-        _context: &CompositionContext,
-    ) -> Result<Arc<dyn PathInfoService>, Box<dyn std::error::Error + Send + Sync + 'static>> {
-        let client = proto::path_info_service_client::PathInfoServiceClient::new(
-            tvix_castore::tonic::channel_from_url(&self.url.parse()?).await?,
-        );
-        Ok(Arc::new(GRPCPathInfoService::from_client(client)))
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use crate::pathinfoservice::tests::make_grpc_path_info_service_client;
diff --git a/tvix/store/src/pathinfoservice/lru.rs b/tvix/store/src/pathinfoservice/lru.rs
index 39c592bc9..da674f497 100644
--- a/tvix/store/src/pathinfoservice/lru.rs
+++ b/tvix/store/src/pathinfoservice/lru.rs
@@ -9,7 +9,6 @@ use tonic::async_trait;
 use tracing::instrument;
 
 use crate::proto::PathInfo;
-use tvix_castore::composition::{CompositionContext, ServiceBuilder};
 use tvix_castore::Error;
 
 use super::PathInfoService;
@@ -61,34 +60,6 @@ impl PathInfoService for LruPathInfoService {
     }
 }
 
-#[derive(serde::Deserialize, Debug)]
-#[serde(deny_unknown_fields)]
-pub struct LruPathInfoServiceConfig {
-    capacity: NonZeroUsize,
-}
-
-impl TryFrom<url::Url> for LruPathInfoServiceConfig {
-    type Error = Box<dyn std::error::Error + Send + Sync>;
-    fn try_from(_url: url::Url) -> Result<Self, Self::Error> {
-        Err(Error::StorageError(
-            "Instantiating a LruPathInfoService from a url is not supported".into(),
-        )
-        .into())
-    }
-}
-
-#[async_trait]
-impl ServiceBuilder for LruPathInfoServiceConfig {
-    type Output = dyn PathInfoService;
-    async fn build<'a>(
-        &'a self,
-        _instance_name: &str,
-        _context: &CompositionContext,
-    ) -> Result<Arc<dyn PathInfoService>, Box<dyn std::error::Error + Send + Sync + 'static>> {
-        Ok(Arc::new(LruPathInfoService::with_capacity(self.capacity)))
-    }
-}
-
 #[cfg(test)]
 mod test {
     use std::num::NonZeroUsize;
diff --git a/tvix/store/src/pathinfoservice/memory.rs b/tvix/store/src/pathinfoservice/memory.rs
index 3fabd239c..3de3221df 100644
--- a/tvix/store/src/pathinfoservice/memory.rs
+++ b/tvix/store/src/pathinfoservice/memory.rs
@@ -7,7 +7,6 @@ use std::{collections::HashMap, sync::Arc};
 use tokio::sync::RwLock;
 use tonic::async_trait;
 use tracing::instrument;
-use tvix_castore::composition::{CompositionContext, ServiceBuilder};
 use tvix_castore::Error;
 
 #[derive(Default)]
@@ -60,30 +59,3 @@ impl PathInfoService for MemoryPathInfoService {
         })
     }
 }
-
-#[derive(serde::Deserialize, Debug)]
-#[serde(deny_unknown_fields)]
-pub struct MemoryPathInfoServiceConfig {}
-
-impl TryFrom<url::Url> for MemoryPathInfoServiceConfig {
-    type Error = Box<dyn std::error::Error + Send + Sync>;
-    fn try_from(url: url::Url) -> Result<Self, Self::Error> {
-        // memory doesn't support host or path in the URL.
-        if url.has_host() || !url.path().is_empty() {
-            return Err(Error::StorageError("invalid url".to_string()).into());
-        }
-        Ok(MemoryPathInfoServiceConfig {})
-    }
-}
-
-#[async_trait]
-impl ServiceBuilder for MemoryPathInfoServiceConfig {
-    type Output = dyn PathInfoService;
-    async fn build<'a>(
-        &'a self,
-        _instance_name: &str,
-        _context: &CompositionContext,
-    ) -> Result<Arc<dyn PathInfoService>, Box<dyn std::error::Error + Send + Sync + 'static>> {
-        Ok(Arc::new(MemoryPathInfoService::default()))
-    }
-}
diff --git a/tvix/store/src/pathinfoservice/mod.rs b/tvix/store/src/pathinfoservice/mod.rs
index 70f752f22..574bcc0b8 100644
--- a/tvix/store/src/pathinfoservice/mod.rs
+++ b/tvix/store/src/pathinfoservice/mod.rs
@@ -14,26 +14,22 @@ mod tests;
 
 use futures::stream::BoxStream;
 use tonic::async_trait;
-use tvix_castore::composition::{Registry, ServiceBuilder};
 use tvix_castore::Error;
 
-use crate::nar::NarCalculationService;
 use crate::proto::PathInfo;
 
-pub use self::combinators::{
-    Cache as CachePathInfoService, CacheConfig as CachePathInfoServiceConfig,
-};
+pub use self::combinators::Cache as CachePathInfoService;
 pub use self::from_addr::from_addr;
-pub use self::grpc::{GRPCPathInfoService, GRPCPathInfoServiceConfig};
-pub use self::lru::{LruPathInfoService, LruPathInfoServiceConfig};
-pub use self::memory::{MemoryPathInfoService, MemoryPathInfoServiceConfig};
-pub use self::nix_http::{NixHTTPPathInfoService, NixHTTPPathInfoServiceConfig};
-pub use self::sled::{SledPathInfoService, SledPathInfoServiceConfig};
+pub use self::grpc::GRPCPathInfoService;
+pub use self::lru::LruPathInfoService;
+pub use self::memory::MemoryPathInfoService;
+pub use self::nix_http::NixHTTPPathInfoService;
+pub use self::sled::SledPathInfoService;
 
 #[cfg(feature = "cloud")]
 mod bigtable;
 #[cfg(feature = "cloud")]
-pub use self::bigtable::{BigtableParameters, BigtablePathInfoService};
+pub use self::bigtable::BigtablePathInfoService;
 
 #[cfg(any(feature = "fuse", feature = "virtiofs"))]
 pub use self::fs::make_fs;
@@ -56,16 +52,12 @@ pub trait PathInfoService: Send + Sync {
     /// Rust doesn't support this as a generic in traits yet. This is the same thing that
     /// [async_trait] generates, but for streams instead of futures.
     fn list(&self) -> BoxStream<'static, Result<PathInfo, Error>>;
-
-    fn nar_calculation_service(&self) -> Option<Box<dyn NarCalculationService>> {
-        None
-    }
 }
 
 #[async_trait]
 impl<A> PathInfoService for A
 where
-    A: AsRef<dyn PathInfoService> + Send + Sync + 'static,
+    A: AsRef<dyn PathInfoService> + Send + Sync,
 {
     async fn get(&self, digest: [u8; 20]) -> Result<Option<PathInfo>, Error> {
         self.as_ref().get(digest).await
@@ -79,19 +71,3 @@ where
         self.as_ref().list()
     }
 }
-
-/// Registers the builtin PathInfoService implementations with the registry
-pub(crate) fn register_pathinfo_services(reg: &mut Registry) {
-    reg.register::<Box<dyn ServiceBuilder<Output = dyn PathInfoService>>, CachePathInfoServiceConfig>("cache");
-    reg.register::<Box<dyn ServiceBuilder<Output = dyn PathInfoService>>, GRPCPathInfoServiceConfig>("grpc");
-    reg.register::<Box<dyn ServiceBuilder<Output = dyn PathInfoService>>, LruPathInfoServiceConfig>("lru");
-    reg.register::<Box<dyn ServiceBuilder<Output = dyn PathInfoService>>, MemoryPathInfoServiceConfig>("memory");
-    reg.register::<Box<dyn ServiceBuilder<Output = dyn PathInfoService>>, NixHTTPPathInfoServiceConfig>("nix");
-    reg.register::<Box<dyn ServiceBuilder<Output = dyn PathInfoService>>, SledPathInfoServiceConfig>("sled");
-    #[cfg(feature = "cloud")]
-    {
-        reg.register::<Box<dyn ServiceBuilder<Output = dyn PathInfoService>>, BigtableParameters>(
-            "bigtable",
-        );
-    }
-}
diff --git a/tvix/store/src/pathinfoservice/nix_http.rs b/tvix/store/src/pathinfoservice/nix_http.rs
index af9234bc0..57fe37f44 100644
--- a/tvix/store/src/pathinfoservice/nix_http.rs
+++ b/tvix/store/src/pathinfoservice/nix_http.rs
@@ -7,15 +7,12 @@ use nix_compat::{
     nixhash::NixHash,
 };
 use reqwest::StatusCode;
-use std::sync::Arc;
 use tokio::io::{self, AsyncRead};
 use tonic::async_trait;
 use tracing::{debug, instrument, warn};
-use tvix_castore::composition::{CompositionContext, ServiceBuilder};
 use tvix_castore::{
     blobservice::BlobService, directoryservice::DirectoryService, proto as castorepb, Error,
 };
-use url::Url;
 
 /// NixHTTPPathInfoService acts as a bridge in between the Nix HTTP Binary cache
 /// protocol provided by Nix binary caches such as cache.nixos.org, and the Tvix
@@ -252,71 +249,3 @@ where
         }))
     }
 }
-
-#[derive(serde::Deserialize)]
-pub struct NixHTTPPathInfoServiceConfig {
-    base_url: String,
-    blob_service: String,
-    directory_service: String,
-    #[serde(default)]
-    /// An optional list of [narinfo::PubKey].
-    /// If set, the .narinfo files received need to have correct signature by at least one of these.
-    public_keys: Option<Vec<String>>,
-}
-
-impl TryFrom<Url> for NixHTTPPathInfoServiceConfig {
-    type Error = Box<dyn std::error::Error + Send + Sync>;
-    fn try_from(url: Url) -> Result<Self, Self::Error> {
-        let mut public_keys: Option<Vec<String>> = None;
-        for (_, v) in url
-            .query_pairs()
-            .into_iter()
-            .filter(|(k, _)| k == "trusted-public-keys")
-        {
-            public_keys
-                .get_or_insert(Default::default())
-                .extend(v.split_ascii_whitespace().map(ToString::to_string));
-        }
-        Ok(NixHTTPPathInfoServiceConfig {
-            // Stringify the URL and remove the nix+ prefix.
-            // We can't use `url.set_scheme(rest)`, as it disallows
-            // setting something http(s) that previously wasn't.
-            base_url: url.to_string().strip_prefix("nix+").unwrap().to_string(),
-            blob_service: "default".to_string(),
-            directory_service: "default".to_string(),
-            public_keys,
-        })
-    }
-}
-
-#[async_trait]
-impl ServiceBuilder for NixHTTPPathInfoServiceConfig {
-    type Output = dyn PathInfoService;
-    async fn build<'a>(
-        &'a self,
-        _instance_name: &str,
-        context: &CompositionContext,
-    ) -> Result<Arc<dyn PathInfoService>, Box<dyn std::error::Error + Send + Sync + 'static>> {
-        let (blob_service, directory_service) = futures::join!(
-            context.resolve(self.blob_service.clone()),
-            context.resolve(self.directory_service.clone())
-        );
-        let mut svc = NixHTTPPathInfoService::new(
-            Url::parse(&self.base_url)?,
-            blob_service?,
-            directory_service?,
-        );
-        if let Some(public_keys) = &self.public_keys {
-            svc.set_public_keys(
-                public_keys
-                    .iter()
-                    .map(|pubkey_str| {
-                        narinfo::PubKey::parse(pubkey_str)
-                            .map_err(|e| Error::StorageError(format!("invalid public key: {e}")))
-                    })
-                    .collect::<Result<Vec<_>, Error>>()?,
-            );
-        }
-        Ok(Arc::new(svc))
-    }
-}
diff --git a/tvix/store/src/pathinfoservice/sled.rs b/tvix/store/src/pathinfoservice/sled.rs
index 4255bfd1d..96ade1816 100644
--- a/tvix/store/src/pathinfoservice/sled.rs
+++ b/tvix/store/src/pathinfoservice/sled.rs
@@ -5,10 +5,8 @@ use futures::stream::BoxStream;
 use nix_compat::nixbase32;
 use prost::Message;
 use std::path::Path;
-use std::sync::Arc;
 use tonic::async_trait;
 use tracing::{instrument, warn};
-use tvix_castore::composition::{CompositionContext, ServiceBuilder};
 use tvix_castore::Error;
 
 /// SledPathInfoService stores PathInfo in a [sled](https://github.com/spacejam/sled).
@@ -116,69 +114,3 @@ impl PathInfoService for SledPathInfoService {
         })
     }
 }
-
-#[derive(serde::Deserialize)]
-#[serde(deny_unknown_fields)]
-pub struct SledPathInfoServiceConfig {
-    is_temporary: bool,
-    #[serde(default)]
-    /// required when is_temporary = false
-    path: Option<String>,
-}
-
-impl TryFrom<url::Url> for SledPathInfoServiceConfig {
-    type Error = Box<dyn std::error::Error + Send + Sync>;
-    fn try_from(url: url::Url) -> Result<Self, Self::Error> {
-        // sled doesn't support host, and a path can be provided (otherwise
-        // it'll live in memory only).
-        if url.has_host() {
-            return Err(Error::StorageError("no host allowed".to_string()).into());
-        }
-
-        // TODO: expose compression and other parameters as URL parameters?
-
-        Ok(if url.path().is_empty() {
-            SledPathInfoServiceConfig {
-                is_temporary: true,
-                path: None,
-            }
-        } else {
-            SledPathInfoServiceConfig {
-                is_temporary: false,
-                path: Some(url.path().to_string()),
-            }
-        })
-    }
-}
-
-#[async_trait]
-impl ServiceBuilder for SledPathInfoServiceConfig {
-    type Output = dyn PathInfoService;
-    async fn build<'a>(
-        &'a self,
-        _instance_name: &str,
-        _context: &CompositionContext,
-    ) -> Result<Arc<dyn PathInfoService>, Box<dyn std::error::Error + Send + Sync + 'static>> {
-        match self {
-            SledPathInfoServiceConfig {
-                is_temporary: true,
-                path: None,
-            } => Ok(Arc::new(SledPathInfoService::new_temporary()?)),
-            SledPathInfoServiceConfig {
-                is_temporary: true,
-                path: Some(_),
-            } => Err(
-                Error::StorageError("Temporary SledPathInfoService can not have path".into())
-                    .into(),
-            ),
-            SledPathInfoServiceConfig {
-                is_temporary: false,
-                path: None,
-            } => Err(Error::StorageError("SledPathInfoService is missing path".into()).into()),
-            SledPathInfoServiceConfig {
-                is_temporary: false,
-                path: Some(path),
-            } => Ok(Arc::new(SledPathInfoService::new(path)?)),
-        }
-    }
-}
diff --git a/tvix/store/src/utils.rs b/tvix/store/src/utils.rs
index a09786386..d82f2214f 100644
--- a/tvix/store/src/utils.rs
+++ b/tvix/store/src/utils.rs
@@ -1,60 +1,18 @@
+use std::sync::Arc;
 use std::{
-    collections::HashMap,
     pin::Pin,
-    sync::Arc,
     task::{self, Poll},
 };
 use tokio::io::{self, AsyncWrite};
 
-use tvix_castore::{blobservice::BlobService, directoryservice::DirectoryService};
+use tvix_castore::{
+    blobservice::{self, BlobService},
+    directoryservice::{self, DirectoryService},
+};
 use url::Url;
 
-use crate::composition::{
-    with_registry, Composition, DeserializeWithRegistry, ServiceBuilder, REG,
-};
 use crate::nar::{NarCalculationService, SimpleRenderer};
-use crate::pathinfoservice::PathInfoService;
-
-#[derive(serde::Deserialize, Default)]
-pub struct CompositionConfigs {
-    pub blobservices:
-        HashMap<String, DeserializeWithRegistry<Box<dyn ServiceBuilder<Output = dyn BlobService>>>>,
-    pub directoryservices: HashMap<
-        String,
-        DeserializeWithRegistry<Box<dyn ServiceBuilder<Output = dyn DirectoryService>>>,
-    >,
-    pub pathinfoservices: HashMap<
-        String,
-        DeserializeWithRegistry<Box<dyn ServiceBuilder<Output = dyn PathInfoService>>>,
-    >,
-}
-
-pub fn addrs_to_configs(
-    blob_service_addr: impl AsRef<str>,
-    directory_service_addr: impl AsRef<str>,
-    path_info_service_addr: impl AsRef<str>,
-) -> Result<CompositionConfigs, Box<dyn std::error::Error + Send + Sync>> {
-    let mut configs: CompositionConfigs = Default::default();
-
-    let blob_service_url = Url::parse(blob_service_addr.as_ref())?;
-    let directory_service_url = Url::parse(directory_service_addr.as_ref())?;
-    let path_info_service_url = Url::parse(path_info_service_addr.as_ref())?;
-
-    configs.blobservices.insert(
-        "default".into(),
-        with_registry(&REG, || blob_service_url.try_into())?,
-    );
-    configs.directoryservices.insert(
-        "default".into(),
-        with_registry(&REG, || directory_service_url.try_into())?,
-    );
-    configs.pathinfoservices.insert(
-        "default".into(),
-        with_registry(&REG, || path_info_service_url.try_into())?,
-    );
-
-    Ok(configs)
-}
+use crate::pathinfoservice::{self, PathInfoService};
 
 /// Construct the store handles from their addrs.
 pub async fn construct_services(
@@ -65,52 +23,49 @@ pub async fn construct_services(
     (
         Arc<dyn BlobService>,
         Arc<dyn DirectoryService>,
-        Arc<dyn PathInfoService>,
+        Box<dyn PathInfoService>,
         Box<dyn NarCalculationService>,
     ),
     Box<dyn std::error::Error + Send + Sync>,
 > {
-    let configs = addrs_to_configs(
-        blob_service_addr,
-        directory_service_addr,
-        path_info_service_addr,
-    )?;
-    construct_services_from_configs(configs).await
-}
-
-/// Construct the store handles from their addrs.
-pub async fn construct_services_from_configs(
-    configs: CompositionConfigs,
-) -> Result<
-    (
-        Arc<dyn BlobService>,
-        Arc<dyn DirectoryService>,
-        Arc<dyn PathInfoService>,
-        Box<dyn NarCalculationService>,
-    ),
-    Box<dyn std::error::Error + Send + Sync>,
-> {
-    let mut comp = Composition::default();
-
-    comp.extend(configs.blobservices);
-    comp.extend(configs.directoryservices);
-    comp.extend(configs.pathinfoservices);
-
-    let blob_service: Arc<dyn BlobService> = comp.build("default").await?;
-    let directory_service: Arc<dyn DirectoryService> = comp.build("default").await?;
-    let path_info_service: Arc<dyn PathInfoService> = comp.build("default").await?;
+    let blob_service: Arc<dyn BlobService> =
+        blobservice::from_addr(blob_service_addr.as_ref()).await?;
+    let directory_service: Arc<dyn DirectoryService> =
+        directoryservice::from_addr(directory_service_addr.as_ref()).await?;
+
+    let path_info_service = pathinfoservice::from_addr(
+        path_info_service_addr.as_ref(),
+        blob_service.clone(),
+        directory_service.clone(),
+    )
+    .await?;
 
     // HACK: The grpc client also implements NarCalculationService, and we
     // really want to use it (otherwise we'd need to fetch everything again for hashing).
     // Until we revamped store composition and config, detect this special case here.
-    let nar_calculation_service: Box<dyn NarCalculationService> = path_info_service
-        .nar_calculation_service()
-        .unwrap_or_else(|| {
+    let nar_calculation_service: Box<dyn NarCalculationService> = {
+        use crate::pathinfoservice::GRPCPathInfoService;
+        use crate::proto::path_info_service_client::PathInfoServiceClient;
+
+        let url = Url::parse(path_info_service_addr.as_ref())
+            .map_err(|e| io::Error::other(e.to_string()))?;
+
+        if url.scheme().starts_with("grpc+") {
+            Box::new(GRPCPathInfoService::from_client(
+                PathInfoServiceClient::with_interceptor(
+                    tvix_castore::tonic::channel_from_url(&url)
+                        .await
+                        .map_err(|e| io::Error::other(e.to_string()))?,
+                    tvix_tracing::propagate::tonic::send_trace,
+                ),
+            ))
+        } else {
             Box::new(SimpleRenderer::new(
                 blob_service.clone(),
                 directory_service.clone(),
-            ))
-        });
+            )) as Box<dyn NarCalculationService>
+        }
+    };
 
     Ok((
         blob_service,