feat: give a more useful error message when VM image already exists

Sponsored-by: author

3 files changed, 29 insertions, 1 deletions

diff --git a/src/cmd/new.rs b/src/cmd/new.rs
index 8583ae9..487914a 100644
--- a/src/cmd/new.rs
+++ b/src/cmd/new.rs
@@ -9,6 +9,7 @@ use crate::spec::Specification;
 use crate::util::wait_for_ssh;
 
 use bytesize::GIB;
+use log::debug;
 use tempfile::tempdir;
 
 /// Errors returned by this module.
@@ -48,13 +49,16 @@ pub fn new(specs: &[Specification], progress: &Progress) -> Result<(), NewError>
 
         progress.chatty("creating cloud-init config");
         let init = CloudInitConfig::from(spec)?;
+        debug!("finished creating cloud-init config");
 
         progress.chatty(&format!(
             "creating VM image {} from {}",
             spec.image.display(),
             spec.base.display()
         ));
+        debug!("creating VM image");
         let image = VirtualMachineImage::new_from_base(&spec.base, &spec.image)?;
+        debug!("finished creating VM image");
 
         progress.chatty(&format!("resizing image to {} GiB", spec.image_size_gib));
         image.resize(spec.image_size_gib * GIB)?;
diff --git a/src/image.rs b/src/image.rs
index 7b7c2ce..ffe5b56 100644
--- a/src/image.rs
+++ b/src/image.rs
@@ -1,5 +1,6 @@
 //! Virtual machine image handling.
 
+use log::debug;
 use std::fs::copy;
 use std::path::{Path, PathBuf};
 use std::process::Command;
@@ -8,6 +9,10 @@ use std::result::Result;
 /// Errors from this module.
 #[derive(Debug, thiserror::Error)]
 pub enum ImageError {
+    /// The image file for a new VM already exists.
+    #[error("image file already exists: {0}")]
+    ImageExists(PathBuf),
+
     /// Error resizing image.
     #[error("qemu-img resize failed: {0}")]
     ResizeError(String),
@@ -34,9 +39,21 @@ pub struct VirtualMachineImage {
 impl VirtualMachineImage {
     /// Create new image from a base image.
     pub fn new_from_base(base_image: &Path, image: &Path) -> Result<Self, ImageError> {
+        debug!(
+            "creating new image {} from base image {}",
+            image.display(),
+            base_image.display()
+        );
+        debug!("does {} exixt? {}", image.display(), image.exists());
+        if image.exists() {
+            debug!("image already exists: {}", image.display());
+            return Err(ImageError::ImageExists(image.to_path_buf()));
+        }
+        debug!("copying base image to new image");
         copy(base_image, image).map_err(|err| {
             ImageError::BaseImageCopy(base_image.to_path_buf(), image.to_path_buf(), err)
         })?;
+        debug!("all good");
         Ok(Self {
             filename: image.to_path_buf(),
         })
diff --git a/src/progress.rs b/src/progress.rs
index 52ade35..5ce56af 100644
--- a/src/progress.rs
+++ b/src/progress.rs
@@ -1,5 +1,7 @@
 //! Show progress, or not.
 
+use log::{debug, error, info};
+
 #[derive(Debug, Clone, Copy)]
 pub enum MessageKind {
     OnlyErrors,
@@ -21,6 +23,7 @@ impl Progress {
     }
 
     pub fn chatty(&self, msg: &str) {
+        debug!("{}", msg);
         if let MessageKind::Everything = self.level {
             self.message("DEBUG", msg);
         }
@@ -28,13 +31,17 @@ impl Progress {
 
     pub fn step(&self, msg: &str) {
         match self.level {
-            MessageKind::Everything | MessageKind::Steps => self.message("INFO", msg),
+            MessageKind::Everything | MessageKind::Steps => {
+                info!("{}", msg);
+                self.message("INFO", msg)
+            }
             _ => (),
         }
     }
 
     pub fn error(&self, msg: &str) {
         // Errors are always written out.
+        error!("{}", msg);
         self.message("ERROR", msg);
     }
 }