feat(services): Add wasi-fs backend using wasi:filesystem interface

.env.example

@@ -2,6 +2,8 @@
 # fs
 OPENDAL_FS_ROOT=/path/to/dir
 OPENDAL_FS_ATOMIC_WRITE_DIR=/path/to/tempdir
+# wasi-fs - WASI Filesystem (requires wasm32-wasip2 target + wasmtime)
+# OPENDAL_WASI_FS_ROOT=/
 # cos
 OPENDAL_COS_BUCKET=opendal-testing-1318209832
 OPENDAL_COS_ENDPOINT=https://cos.ap-singapore.myqcloud.com

.github/workflows/test_wasi_fs.yml

@@ -0,0 +1,58 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+name: Check WASI-FS Service
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - 'core/services/wasi-fs/**'
+      - 'core/core/src/**'
+      - '.github/workflows/test_wasi_fs.yml'
+  pull_request:
+    branches: [main]
+    paths:
+      - 'core/services/wasi-fs/**'
+      - 'core/core/src/**'
+      - '.github/workflows/test_wasi_fs.yml'
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+
+      - name: Setup Rust toolchain
+        uses: ./.github/actions/setup
+
+      - name: Add wasm32-wasip2 target
+        run: rustup target add wasm32-wasip2
+
+      # Verify the wasi-fs service compiles for the WASI target.
+      # Note: Full behavior tests cannot run because tokio doesn't support wasm32-wasip2.
+      # The service uses blocking WASI Preview 2 APIs which work correctly at runtime.
+      - name: Check wasi-fs compiles
+        working-directory: core
+        run: |
+          cargo check --target wasm32-wasip2 \
+            --features services-wasi-fs \
+            -p opendal

core/Cargo.toml

@@ -162,6 +162,7 @@ services-vercel-artifacts = ["opendal-core/services-vercel-artifacts"]
 services-vercel-blob = ["dep:opendal-service-vercel-blob"]
 services-webdav = ["opendal-core/services-webdav"]
 services-webhdfs = ["opendal-core/services-webhdfs"]
+services-wasi-fs = ["dep:opendal-service-wasi-fs"]
 services-yandex-disk = ["opendal-core/services-yandex-disk"]
 tests = ["opendal-core/tests"]
 
@@ -218,6 +219,7 @@ opendal-service-sled = { path = "services/sled", version = "0.55.0", optional =
 opendal-service-s3 = { path = "services/s3", version = "0.55.0", optional = true, default-features = false }
 opendal-service-tikv = { path = "services/tikv", version = "0.55.0", optional = true, default-features = false }
 opendal-service-vercel-blob = { path = "services/vercel-blob", version = "0.55.0", optional = true, default-features = false }
+opendal-service-wasi-fs = { path = "services/wasi-fs", version = "0.55.0", optional = true, default-features = false }
 
 [dev-dependencies]
 anyhow = { version = "1.0.100", features = ["std"] }

core/core/src/raw/time.rs

@@ -24,9 +24,11 @@ use std::ops::{Add, AddAssign, Sub, SubAssign};
 use std::str::FromStr;
 
 pub use std::time::{Duration, UNIX_EPOCH};
-#[cfg(not(target_arch = "wasm32"))]
+// For native and WASI targets, use std::time
+#[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
 pub use std::time::{Instant, SystemTime};
-#[cfg(target_arch = "wasm32")]
+// For browser wasm (target_os = "unknown"), use web_time
+#[cfg(all(target_arch = "wasm32", target_os = "unknown"))]
 pub use web_time::{Instant, SystemTime};
 
 /// An instant in time represented as the number of nanoseconds since the Unix epoch.
@@ -179,12 +181,14 @@ impl From<jiff::Timestamp> for Timestamp {
 
 impl From<Timestamp> for SystemTime {
     fn from(ts: Timestamp) -> Self {
-        #[cfg(not(target_arch = "wasm32"))]
+        // For native and WASI targets, use std::time directly
+        #[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
         {
             SystemTime::from(ts.0)
         }
 
-        #[cfg(target_arch = "wasm32")]
+        // For browser wasm (target_os = "unknown"), use web_time
+        #[cfg(all(target_arch = "wasm32", target_os = "unknown"))]
         {
             use std::time::SystemTime as StdSystemTime;
 
@@ -199,12 +203,14 @@ impl TryFrom<SystemTime> for Timestamp {
 
     fn try_from(t: SystemTime) -> Result<Self> {
         let t = {
-            #[cfg(not(target_arch = "wasm32"))]
+            // For native and WASI targets, use std::time directly
+            #[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
             {
                 t
             }
 
-            #[cfg(target_arch = "wasm32")]
+            // For browser wasm (target_os = "unknown"), use web_time
+            #[cfg(all(target_arch = "wasm32", target_os = "unknown"))]
             {
                 <web_time::SystemTime as web_time::web::SystemTimeExt>::to_std(t)
             }

core/scripts/test_wasi_fs.sh

@@ -0,0 +1,59 @@
+#!/bin/bash
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+# Test runner for wasi-fs service
+# Requires: wasmtime, wasm32-wasip2 target
+
+set -e
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+CORE_DIR="$(dirname "$SCRIPT_DIR")"
+TEST_DIR="${TEST_DIR:-/tmp/opendal-wasi-fs-test}"
+
+echo "=== WASI-FS Behavior Test Runner ==="
+echo "Test directory: $TEST_DIR"
+
+# Create test directory
+mkdir -p "$TEST_DIR"
+
+# Build behavior tests for wasm32-wasip2
+echo "Building behavior tests for wasm32-wasip2..."
+cd "$CORE_DIR"
+cargo build --tests --target wasm32-wasip2 --features tests,services-wasi-fs
+
+# Find the test binary
+TEST_BINARY=$(find target/wasm32-wasip2/debug/deps -name "behavior-*.wasm" | head -1)
+
+if [ -z "$TEST_BINARY" ]; then
+    echo "Error: Could not find behavior test binary"
+    exit 1
+fi
+
+echo "Running tests with wasmtime..."
+echo "Binary: $TEST_BINARY"
+
+# Run with wasmtime, granting access to test directory
+OPENDAL_TEST=wasi-fs \
+OPENDAL_WASI_FS_ROOT=/ \
+wasmtime run \
+    --dir "$TEST_DIR::/" \
+    --env "OPENDAL_TEST=wasi-fs" \
+    --env "OPENDAL_WASI_FS_ROOT=/" \
+    "$TEST_BINARY"
+
+echo "=== Tests completed ==="

core/services/wasi-fs/Cargo.toml

@@ -0,0 +1,40 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+[package]
+description = "Apache OpenDAL WASI filesystem service implementation"
+name = "opendal-service-wasi-fs"
+
+authors = { workspace = true }
+edition = { workspace = true }
+homepage = { workspace = true }
+license = { workspace = true }
+repository = { workspace = true }
+rust-version = { workspace = true }
+version = { workspace = true }
+
+[package.metadata.docs.rs]
+all-features = true
+
+[dependencies]
+opendal-core = { path = "../../core", version = "0.55.0", default-features = false }
+
+ctor = { workspace = true }
+serde = { workspace = true, features = ["derive"] }
+
+[target.'cfg(all(target_arch = "wasm32", target_os = "wasi"))'.dependencies]
+wasi = "0.14.7"