Implement proper caching in VM builder v2

.gitignore

@@ -1,2 +1,3 @@
 target/
 .vscode/
+.cache/

Cargo.toml

@@ -27,7 +27,7 @@ toml = "0.8.19"
 openssl = { version = "*", optional = true }
 
 # Linux VM builder dependencies
-mia-installer = { git = "https://github.com/gevulotnetwork/mia.git", tag = "mia-installer-0.2.5" }
+mia-installer = { git = "https://github.com/gevulotnetwork/mia.git", tag = "mia-installer-0.3.0" }
 
 anyhow = "1"
 log = "0.4.22"
@@ -38,7 +38,9 @@ thiserror = "1"
 
 # Linux VM builder v2 dependencies
 backhand = { version = "0.20", optional = true, default-features = false, features = ["xz"] }
+base64 = { version = "0.22", optional = true }
 bytesize = { version = "1", optional = true }
+crc = { version = "3", optional = true }
 directories = { version = "5", optional = true }
 fatfs = { version = "0.3", optional = true }
 fscommon = { version = "0.1", optional = true }
@@ -60,7 +62,9 @@ openssl-vendored = ["openssl/vendored"]
 # Use new version of Linux VM builder (unstable)
 vm-builder-v2 = [
     "dep:backhand",
+    "dep:base64",
     "dep:bytesize",
+    "dep:crc",
     "dep:directories",
     "dep:fatfs",
     "dep:fscommon",

src/builders_v2/linux_vm/image_file.rs

@@ -181,8 +181,11 @@ pub struct UseImageFile;
 
 impl Step<LinuxVMBuildContext> for UseImageFile {
     fn run(&mut self, ctx: &mut LinuxVMBuildContext) -> Result<()> {
-        let base_image_path = ctx.cache().join("base.img");
-        if !base_image_path.exists() {
+        let crc_instance = crc::Crc::<u64>::new(&crc::CRC_64_ECMA_182);
+        let checksum = format!("{:x}", crc_instance.checksum(BASE_IMAGE));
+        debug!("base image checksum: {}", &checksum);
+        let base_image_path = ctx.cache().join(format!("{}.base.img", checksum));
+        if !base_image_path.is_file() {
             info!("creating base image file: {}", base_image_path.display());
             let mut file = fs::File::create_new(&base_image_path)
                 .context("failed to create base image file")?;