initial flush path lister implementation (#241)

changes by @calccrypto
Given a DAL root, scan the files in the leaf directories and print the
paths of files that should be flushed based on system utilization and
user provided thresholds.

Usage: flush_ls <ROOT> <REFTIME> <THRESHOLDS>...

.github/workflows/ci.yml

@@ -20,14 +20,14 @@ jobs:
         mkdir install
 
     - name: Checkout ISA-L
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         repository: intel/isa-l
         ref: v2.30.0
         path: isa-l
 
     - name: Checkout MarFS
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         path: marfs
 
@@ -49,3 +49,19 @@ jobs:
         make install
         cd $GITHUB_WORKSPACE
 
+  # https://doc.rust-lang.org/cargo/guide/continuous-integration.html
+  flush_ls:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Update Toolchain
+        run: rustup update stable && rustup default stable
+
+      - name: Build
+        run: cargo build --verbose
+        working-directory: flush_ls
+
+      - name: Test
+        run: cargo test --verbose
+        working-directory: flush_ls

flush_ls/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "flush_ls"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+clap = { version = "4.5.20", features = ["derive"] }
+errno = "0.3.9"
+libc = "0.2.161"
+tempfile = "3.13.0"