feat(tvix/store/blobsvc): add from_addr

This allows constructing blob stores with a URL syntax at runtime,
by passing the --blob-service-addr arg.

We probably still want to have some builder pattern here, to allow
additional schemes to be registered.

Change-Id: Ie588ff7a7c6fb64c9474dfbd2e4bc5f168dfd778
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8742
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI

tvix/store/src/blobservice/from_addr.rs

@@ -0,0 +1,31 @@
+use std::sync::Arc;
+use url::Url;
+
+use super::{BlobService, GRPCBlobService, MemoryBlobService, SledBlobService};
+
+/// Constructs a new instance of a [BlobService] from an URI.
+///
+/// The following schemes are supported by the following services:
+/// - `memory://` ([MemoryBlobService])
+/// - `sled://` ([SledBlobService])
+/// - `grpc+*://` ([GRPCBlobService])
+///
+/// See their [from_url] methods for more details about their syntax.
+pub async fn from_addr(uri: &str) -> Result<Arc<dyn BlobService>, crate::Error> {
+    let url = Url::parse(uri).map_err(|e| {
+        crate::Error::StorageError(format!("unable to parse url: {}", e.to_string()))
+    })?;
+
+    Ok(if url.scheme() == "memory" {
+        Arc::new(MemoryBlobService::from_url(&url)?)
+    } else if url.scheme() == "sled" {
+        Arc::new(SledBlobService::from_url(&url)?)
+    } else if url.scheme().starts_with("grpc+") {
+        Arc::new(GRPCBlobService::from_url(&url)?)
+    } else {
+        Err(crate::Error::StorageError(format!(
+            "unknown scheme: {}",
+            url.scheme()
+        )))?
+    })
+}

tvix/store/src/blobservice/grpc.rs

@@ -2,7 +2,7 @@ use super::{BlobService, BlobWriter};
 use crate::{proto, B3Digest};
 use futures::sink::{SinkExt, SinkMapErr};
 use std::{collections::VecDeque, io};
-use tokio::task::JoinHandle;
+use tokio::{net::UnixStream, task::JoinHandle};
 use tokio_stream::{wrappers::ReceiverStream, StreamExt};
 use tokio_util::{
     io::{CopyToBytes, SinkWriter, SyncIoBridge},
@@ -36,6 +36,58 @@ impl GRPCBlobService {
 }
 
 impl BlobService for GRPCBlobService {
+    /// Constructs a [GRPCBlobService] from the passed [url::Url]:
+    /// - scheme has to match `grpc+*://`.
+    ///   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.
+    fn from_url(url: &url::Url) -> Result<Self, crate::Error> {
+        // Start checking for the scheme to start with grpc+.
+        match url.scheme().strip_prefix("grpc+") {
+            None => Err(crate::Error::StorageError("invalid scheme".to_string())),
+            Some(rest) => {
+                if rest == "unix" {
+                    if url.host_str().is_some() {
+                        return Err(crate::Error::StorageError(
+                            "host may not be set".to_string(),
+                        ));
+                    }
+                    let path = url.path().to_string();
+                    let channel = tonic::transport::Endpoint::try_from("http://[::]:50051") // doesn't matter
+                        .unwrap()
+                        .connect_with_connector_lazy(tower::service_fn(
+                            move |_: tonic::transport::Uri| UnixStream::connect(path.clone()),
+                        ));
+                    let grpc_client = proto::blob_service_client::BlobServiceClient::new(channel);
+                    Ok(Self::from_client(grpc_client))
+                } else {
+                    // ensure path is empty, not supported with gRPC.
+                    if !url.path().is_empty() {
+                        return Err(crate::Error::StorageError(
+                            "path may not be set".to_string(),
+                        ));
+                    }
+
+                    // clone the uri, and drop the grpc+ from the scheme.
+                    // Recreate a new uri with the `grpc+` prefix dropped from the scheme.
+                    // We can't use `url.set_scheme(rest)`, as it disallows
+                    // setting something http(s) that previously wasn't.
+                    let url = {
+                        let url_str = url.to_string();
+                        let s_stripped = url_str.strip_prefix("grpc+").unwrap();
+                        url::Url::parse(s_stripped).unwrap()
+                    };
+                    let channel = tonic::transport::Endpoint::try_from(url.to_string())
+                        .unwrap()
+                        .connect_lazy();
+
+                    let grpc_client = proto::blob_service_client::BlobServiceClient::new(channel);
+                    Ok(Self::from_client(grpc_client))
+                }
+            }
+        }
+    }
+
     #[instrument(skip(self, digest), fields(blob.digest=%digest))]
     fn has(&self, digest: &B3Digest) -> Result<bool, crate::Error> {
         // Get a new handle to the gRPC client, and copy the digest.
@@ -236,3 +288,148 @@ impl io::Write for GRPCBlobWriter {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use std::sync::Arc;
+    use std::thread;
+
+    use tempfile::TempDir;
+    use tokio::net::UnixListener;
+    use tokio::task;
+    use tokio::time;
+    use tokio_stream::wrappers::UnixListenerStream;
+
+    use crate::blobservice::MemoryBlobService;
+    use crate::proto::GRPCBlobServiceWrapper;
+    use crate::tests::fixtures;
+
+    use super::BlobService;
+    use super::GRPCBlobService;
+
+    /// This uses the wrong scheme
+    #[test]
+    fn test_invalid_scheme() {
+        let url = url::Url::parse("http://foo.example/test").expect("must parse");
+
+        assert!(GRPCBlobService::from_url(&url).is_err());
+    }
+
+    /// This uses the correct scheme for a unix socket.
+    /// The fact that /path/to/somewhere doesn't exist yet is no problem, because we connect lazily.
+    #[tokio::test]
+    async fn test_valid_unix_path() {
+        let url = url::Url::parse("grpc+unix:///path/to/somewhere").expect("must parse");
+
+        assert!(GRPCBlobService::from_url(&url).is_ok());
+    }
+
+    /// This uses the correct scheme for a unix socket,
+    /// but sets a host, which is unsupported.
+    #[tokio::test]
+    async fn test_invalid_unix_path_with_domain() {
+        let url =
+            url::Url::parse("grpc+unix://host.example/path/to/somewhere").expect("must parse");
+
+        assert!(GRPCBlobService::from_url(&url).is_err());
+    }
+
+    /// This uses the correct scheme for a HTTP server.
+    /// The fact that nothing is listening there is no problem, because we connect lazily.
+    #[tokio::test]
+    async fn test_valid_http() {
+        let url = url::Url::parse("grpc+http://localhost").expect("must parse");
+
+        assert!(GRPCBlobService::from_url(&url).is_ok());
+    }
+
+    /// This uses the correct scheme for a HTTPS server.
+    /// The fact that nothing is listening there is no problem, because we connect lazily.
+    #[tokio::test]
+    async fn test_valid_https() {
+        let url = url::Url::parse("grpc+https://localhost").expect("must parse");
+
+        assert!(GRPCBlobService::from_url(&url).is_ok());
+    }
+
+    /// This uses the correct scheme, but also specifies
+    /// an additional path, which is not supported for gRPC.
+    /// The fact that nothing is listening there is no problem, because we connect lazily.
+    #[tokio::test]
+    async fn test_invalid_http_with_path() {
+        let url = url::Url::parse("grpc+https://localhost/some-path").expect("must parse");
+
+        assert!(GRPCBlobService::from_url(&url).is_err());
+    }
+
+    /// This uses the correct scheme for a unix socket, and provides a server on the other side.
+    #[tokio::test]
+    async fn test_valid_unix_path_ping_pong() {
+        let tmpdir = TempDir::new().unwrap();
+        let path = tmpdir.path().join("daemon");
+
+        // let mut join_set = JoinSet::new();
+
+        // prepare a client
+        let client = {
+            let mut url = url::Url::parse("grpc+unix:///path/to/somewhere").expect("must parse");
+            url.set_path(path.to_str().unwrap());
+            GRPCBlobService::from_url(&url).expect("must succeed")
+        };
+
+        let path_copy = path.clone();
+
+        // Spin up a server, in a thread far away, which spawns its own tokio runtime,
+        // and blocks on the task.
+        thread::spawn(move || {
+            // Create the runtime
+            let rt = tokio::runtime::Runtime::new().unwrap();
+            // Get a handle from this runtime
+            let handle = rt.handle();
+
+            let task = handle.spawn(async {
+                let uds = UnixListener::bind(path_copy).unwrap();
+                let uds_stream = UnixListenerStream::new(uds);
+
+                // spin up a new server
+                let mut server = tonic::transport::Server::builder();
+                let router =
+                    server.add_service(crate::proto::blob_service_server::BlobServiceServer::new(
+                        GRPCBlobServiceWrapper::from(
+                            Arc::new(MemoryBlobService::default()) as Arc<dyn BlobService>
+                        ),
+                    ));
+                router.serve_with_incoming(uds_stream).await
+            });
+
+            handle.block_on(task)
+        });
+
+        // wait for the socket to be created
+        {
+            let mut socket_created = false;
+            for _try in 1..20 {
+                if path.exists() {
+                    socket_created = true;
+                    break;
+                }
+                tokio::time::sleep(time::Duration::from_millis(20)).await;
+            }
+
+            assert!(
+                socket_created,
+                "expected socket path to eventually get created, but never happened"
+            );
+        }
+
+        let has = task::spawn_blocking(move || {
+            println!("client has?");
+            client
+                .has(&fixtures::BLOB_A_DIGEST)
+                .expect("must not be err")
+        })
+        .await
+        .expect("must not be err");
+        assert!(!has);
+    }
+}

tvix/store/src/blobservice/memory.rs

@@ -14,6 +14,22 @@ pub struct MemoryBlobService {
 }
 
 impl BlobService for MemoryBlobService {
+    /// Constructs a [MemoryBlobService] from the passed [url::Url]:
+    /// - scheme has to be `memory://`
+    /// - there may not be a host.
+    /// - there may not be a path.
+    fn from_url(url: &url::Url) -> Result<Self, Error> {
+        if url.scheme() != "memory" {
+            return Err(crate::Error::StorageError("invalid scheme".to_string()));
+        }
+
+        if url.has_host() || !url.path().is_empty() {
+            return Err(crate::Error::StorageError("invalid url".to_string()));
+        }
+
+        Ok(Self::default())
+    }
+
     #[instrument(skip(self, digest), fields(blob.digest=%digest))]
     fn has(&self, digest: &B3Digest) -> Result<bool, Error> {
         let db = self.db.read().unwrap();
@@ -113,3 +129,49 @@ impl BlobWriter for MemoryBlobWriter {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::BlobService;
+    use super::MemoryBlobService;
+
+    /// This uses a wrong scheme.
+    #[test]
+    fn test_invalid_scheme() {
+        let url = url::Url::parse("http://foo.example/test").expect("must parse");
+
+        assert!(MemoryBlobService::from_url(&url).is_err());
+    }
+
+    /// This correctly sets the scheme, and doesn't set a path.
+    #[test]
+    fn test_valid_scheme() {
+        let url = url::Url::parse("memory://").expect("must parse");
+
+        assert!(MemoryBlobService::from_url(&url).is_ok());
+    }
+
+    /// This sets the host to `foo`
+    #[test]
+    fn test_invalid_host() {
+        let url = url::Url::parse("memory://foo").expect("must parse");
+
+        assert!(MemoryBlobService::from_url(&url).is_err());
+    }
+
+    /// This has the path "/", which is invalid.
+    #[test]
+    fn test_invalid_has_path() {
+        let url = url::Url::parse("memory:///").expect("must parse");
+
+        assert!(MemoryBlobService::from_url(&url).is_err());
+    }
+
+    /// This has the path "/foo", which is invalid.
+    #[test]
+    fn test_invalid_path2() {
+        let url = url::Url::parse("memory:///foo").expect("must parse");
+
+        assert!(MemoryBlobService::from_url(&url).is_err());
+    }
+}

tvix/store/src/blobservice/mod.rs

@@ -2,10 +2,12 @@ use std::io;
 
 use crate::{B3Digest, Error};
 
+mod from_addr;
 mod grpc;
 mod memory;
 mod sled;
 
+pub use self::from_addr::from_addr;
 pub use self::grpc::GRPCBlobService;
 pub use self::memory::MemoryBlobService;
 pub use self::sled::SledBlobService;
@@ -16,6 +18,11 @@ pub use self::sled::SledBlobService;
 /// Blob, which will return something implmenting io::Write, and providing a
 /// close funtion, to finalize a blob and get its digest.
 pub trait BlobService: Send + Sync {
+    /// Create a new instance by passing in a connection URL.
+    fn from_url(url: &url::Url) -> Result<Self, Error>
+    where
+        Self: Sized;
+
     /// Check if the service has the blob, by its content hash.
     fn has(&self, digest: &B3Digest) -> Result<bool, Error>;
 

tvix/store/src/blobservice/sled.rs

@@ -28,6 +28,36 @@ impl SledBlobService {
 }
 
 impl BlobService for SledBlobService {
+    /// Constructs a [SledBlobService] from the passed [url::Url]:
+    /// - scheme has to be `sled://`
+    /// - there may not be a host.
+    /// - a path to the sled needs to be provided (which may not be `/`).
+    fn from_url(url: &url::Url) -> Result<Self, Error> {
+        if url.scheme() != "sled" {
+            return Err(crate::Error::StorageError("invalid scheme".to_string()));
+        }
+
+        if url.has_host() {
+            return Err(crate::Error::StorageError(format!(
+                "invalid host: {}",
+                url.host().unwrap()
+            )));
+        }
+
+        // TODO: expose compression and other parameters as URL parameters, drop new and new_temporary?
+        if url.path().is_empty() {
+            Self::new_temporary().map_err(|e| Error::StorageError(e.to_string()))
+        } else {
+            if url.path() == "/" {
+                Err(crate::Error::StorageError(
+                    "cowardly refusing to open / with sled".to_string(),
+                ))
+            } else {
+                Self::new(url.path().into()).map_err(|e| Error::StorageError(e.to_string()))
+            }
+        }
+    }
+
     #[instrument(skip(self), fields(blob.digest=%digest))]
     fn has(&self, digest: &B3Digest) -> Result<bool, Error> {
         match self.db.contains_key(digest.to_vec()) {
@@ -127,3 +157,77 @@ impl BlobWriter for SledBlobWriter {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use tempfile::TempDir;
+
+    use super::BlobService;
+    use super::SledBlobService;
+
+    /// This uses a wrong scheme.
+    #[test]
+    fn test_invalid_scheme() {
+        let url = url::Url::parse("http://foo.example/test").expect("must parse");
+
+        assert!(SledBlobService::from_url(&url).is_err());
+    }
+
+    /// This uses the correct scheme, and doesn't specify a path (temporary sled).
+    #[test]
+    fn test_valid_scheme_temporary() {
+        let url = url::Url::parse("sled://").expect("must parse");
+
+        assert!(SledBlobService::from_url(&url).is_ok());
+    }
+
+    /// This sets the path to a location that doesn't exist, which should fail (as sled doesn't mkdir -p)
+    #[test]
+    fn test_nonexistent_path() {
+        let tmpdir = TempDir::new().unwrap();
+
+        let mut url = url::Url::parse("sled://foo.example").expect("must parse");
+        url.set_path(tmpdir.path().join("foo").join("bar").to_str().unwrap());
+
+        assert!(SledBlobService::from_url(&url).is_err());
+    }
+
+    /// This uses the correct scheme, and specifies / as path (which should fail
+    // for obvious reasons)
+    #[test]
+    fn test_invalid_path_root() {
+        let url = url::Url::parse("sled:///").expect("must parse");
+
+        assert!(SledBlobService::from_url(&url).is_err());
+    }
+
+    /// This uses the correct scheme, and sets a tempdir as location.
+    #[test]
+    fn test_valid_scheme_path() {
+        let tmpdir = TempDir::new().unwrap();
+
+        let mut url = url::Url::parse("sled://").expect("must parse");
+        url.set_path(tmpdir.path().to_str().unwrap());
+
+        assert!(SledBlobService::from_url(&url).is_ok());
+    }
+
+    /// This sets a host, rather than a path, which should fail.
+    #[test]
+    fn test_invalid_host() {
+        let url = url::Url::parse("sled://foo.example").expect("must parse");
+
+        assert!(SledBlobService::from_url(&url).is_err());
+    }
+
+    /// This sets a host AND a valid path, which should fail
+    #[test]
+    fn test_invalid_host_and_path() {
+        let tmpdir = TempDir::new().unwrap();
+
+        let mut url = url::Url::parse("sled://foo.example").expect("must parse");
+        url.set_path(tmpdir.path().to_str().unwrap());
+
+        assert!(SledBlobService::from_url(&url).is_err());
+    }
+}