[pve-devel] [PATCH pve-esxi-import-tools 1/1] improve error handling before mounting

[Dominik Csapak]

when we fail early in the mount process, we did not log any error to the
syslog, but only the top most one to stderr.

sadly we were not able to see them anywhere, so improve the log by
* log the complete error chain with log::error (so we also can see the
  causes)
* add more context hints in main_do

This can help debug issues where we failed early and could not see any
error output otherwise, e.g. this thread in the forum:

https://forum.proxmox.com/threads/146248/

Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
---
 src/main.rs | 36 +++++++++++++++++++++++++++---------
 1 file changed, 27 insertions(+), 9 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 281ec3d..a8b2bb6 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,4 +1,5 @@
 use std::ffi::{CString, OsStr, OsString};
+use std::fmt::Write;
 use std::io;
 use std::os::fd::RawFd;
 use std::os::unix::ffi::OsStrExt;
@@ -221,7 +222,12 @@ fn main() {
     });
 
     if let Err(err) = runtime.block_on(main_do()) {
-        eprintln!("Error: {}", err);
+        let mut err_chain = String::new();
+        for err in err.chain() {
+            let _ = writeln!(err_chain, " {err}");
+        }
+        println!("Error: {err}");
+        log::error!("Error: {err_chain}");
         std::process::exit(-1);
     }
 }
@@ -236,15 +242,15 @@ async fn main_do() -> Result<(), Error> {
             usage(&arg0, std::io::stderr(), 1);
         }
     };
-    parse_manifest(&args.manifest)?;
+    parse_manifest(&args.manifest).context("failed to parse manifest")?;
 
     let change_uid = match args.change_user.as_deref() {
-        Some(user) => Some(get_uid(user)?),
+        Some(user) => Some(get_uid(user).context("failed to get uid")?),
         None => None,
     };
 
     let change_gid = match args.change_group.as_deref() {
-        Some(group) => Some(get_gid(group)?),
+        Some(group) => Some(get_gid(group).context("failed to get gid")?),
         None => None,
     };
 
@@ -255,10 +261,12 @@ async fn main_do() -> Result<(), Error> {
         .enable_readdirplus();
 
     for opt in args.mount_options {
-        fuse = fuse.options_os(&opt)?;
+        fuse = fuse
+            .options_os(&opt)
+            .context("failed to get fuse options")?;
     }
 
-    unmount_if_mounted(&args.mount_path)?;
+    unmount_if_mounted(&args.mount_path).context("failed to unmount")?;
 
     let mut fuse = fuse
         .build()
@@ -302,9 +310,19 @@ async fn main_do() -> Result<(), Error> {
             let fs_datastore = fs_datacenter.create_datastore(datastore);
 
             log::debug!("loading {datacenter:?}/{datastore:?}/{path:?}");
-            let config =
-                vmx::VmConfig::parse(client.open_file(datacenter, datastore, path).await?, path)
-                    .await?;
+            let config = vmx::VmConfig::parse(
+                client
+                    .open_file(datacenter, datastore, path)
+                    .await
+                    .with_context(|| {
+                        format!("error opening file for: {datacenter} {datastore} {path}")
+                    })?,
+                path,
+            )
+            .await
+            .with_context(|| {
+                format!("failed to parse vm config for {datacenter} {datastore} {path}")
+            })?;
             log::debug!("{config:#?}");
             for disk in config.disks.values() {
                 let other_fs_datastore;
-- 
2.39.2