Add NFS server mode for ATLAS metadata filesystem

Cargo.toml

@@ -9,3 +9,7 @@ libc = "0.2"
 env_logger = "0.11"
 log = "0.4"
 serde_json = "1"
+nfsserve = "0.11"
+async-trait = "0.1"
+tokio = { version = "1", features = ["macros", "rt-multi-thread"] }
+tracing-subscriber = "0.3"

README.md

@@ -14,6 +14,8 @@ as a directory containing a `metadata.json` file.
       metadata.json
 ```
 
+FUSE mounting and NFS serving are supported directly. The same ATLAS tree can also be materialized to a real directory when a static export is useful.
+
 ## Requirements
 
 ### Linux
@@ -48,13 +50,13 @@ mkdir -p data
 cp /path/to/2024_11_18_ATLAS_info.tsv data/
 ```
 
-## Run
+## Run with FUSE
 
 Build and mount the filesystem:
 
 ```bash
 mkdir -p /tmp/atlas_mount
-cargo run --release -- data/2024_11_18_ATLAS_info.tsv /tmp/atlas_mount
+cargo run --release -- fuse data/2024_11_18_ATLAS_info.tsv /tmp/atlas_mount
 ```
 
 Leave that command running while the filesystem is mounted.
@@ -81,3 +83,35 @@ macOS:
 ```bash
 diskutil unmount /tmp/atlas_mount
 ```
+
+## Materialize To Disk
+
+Write the same ATLAS filesystem tree to a real directory:
+
+```bash
+rm -rf /tmp/atlas_export
+cargo run --release -- materialize data/2024_11_18_ATLAS_info.tsv /tmp/atlas_export
+ls /tmp/atlas_export/atlas | head
+cat /tmp/atlas_export/atlas/1r6w_A/metadata.json
+```
+
+The `/tmp/atlas_export` directory can then be exported with the system NFS server.
+
+## Run With NFS
+
+Start the NFS server:
+
+```bash
+cargo run --release -- nfs data/2024_11_18_ATLAS_info.tsv 127.0.0.1:11111
+```
+In another terminal, mount it.
+
+macOS:
+
+```bash
+mkdir -p /tmp/atlas_nfs
+mount_nfs -o nolocks,vers=3,tcp,rsize=131072,actimeo=120,port=11111,mountport=11111 localhost:/ /tmp/atlas_nfs
+ls /tmp/atlas_nfs/atlas | head
+cat /tmp/atlas_nfs/atlas/1r6w_A/metadata.json
+diskutil unmount /tmp/atlas_nfs
+```