Re: [pbs-devel] [PATCH proxmox-backup] fix #3323: dry-run for cli backup subcommand

[Thomas Lamprecht <t.lamprecht@proxmox.com>]

On 17.02.22 13:58, Markus Frank wrote:
> adds a dry-run parameter for "proxmox-backup-client backup".
> With this parameter on, it simply prints out what would be uploaded,
> instead of uploading it.
> 

looks ok in general, some comments to code style, or better said, refactor
potential inline.

> Signed-off-by: Markus Frank <m.frank@proxmox.com>
> ---
>  proxmox-backup-client/src/main.rs | 194 +++++++++++++++++-------------
>  1 file changed, 112 insertions(+), 82 deletions(-)
> 
> diff --git a/proxmox-backup-client/src/main.rs b/proxmox-backup-client/src/main.rs
> index 081028f2..b992695c 100644
> --- a/proxmox-backup-client/src/main.rs
> +++ b/proxmox-backup-client/src/main.rs
> @@ -613,6 +613,11 @@ fn spawn_catalog_upload(
>                 description: "Verbose output.",
>                 optional: true,
>             },
> +           "dry-run": {
> +               type: Boolean,
> +               description: "Just show what backup would do, but do not upload anything.",
> +               optional: true,
> +           },
>         }
>     }
>  )]
> @@ -633,6 +638,8 @@ async fn create_backup(
>  
>      let verbose = param["verbose"].as_bool().unwrap_or(false);
>  
> +    let dry_run = param["dry-run"].as_bool().unwrap_or(false);
> +
>      let backup_time_opt = param["backup-time"].as_i64();
>  
>      let chunk_size_opt = param["chunk-size"].as_u64().map(|v| (v*1024) as usize);
> @@ -845,94 +852,117 @@ async fn create_backup(
>      let mut catalog_result_rx = None;
>  
>      for (backup_type, filename, target, size) in upload_list {
> -        match backup_type {


did you tried of either matching the tuple (backup_type, dry_run) or using if's in
the match arm, e.g., something like:

match backup_type {
    BackupSpecificationType::CONFIG if dry_run => printdry("config file", filename),
    BackupSpecificationType::LOGFILE if dry_run => printdry("log file", filename),
    ...
    BackupSpecificationType::CONFIG => {
        let upload_options = UploadOptions {
        ...
    },
    ...,
}

The one with matching the tuple has the slight advantage of ensuring that we'd ensure
to always cover all possibilities, that'd be relevant e.g., if a new type gets added
to avoid it's send by mistake if one forgot to add an explicit dry run here, i.e.,
something that your current solution also avoids.

> -            BackupSpecificationType::CONFIG => {
> -                let upload_options = UploadOptions {
> -                    compress: true,
> -                    encrypt: crypto.mode == CryptMode::Encrypt,
> -                    ..UploadOptions::default()
> -                };
> -
> -                println!("Upload config file '{}' to '{}' as {}", filename, repo, target);
> -                let stats = client
> -                    .upload_blob_from_file(&filename, &target, upload_options)
> -                    .await?;
> -                manifest.add_file(target, stats.size, stats.csum, crypto.mode)?;
> -            }
> -            BackupSpecificationType::LOGFILE => { // fixme: remove - not needed anymore ?
> -                let upload_options = UploadOptions {
> -                    compress: true,
> -                    encrypt: crypto.mode == CryptMode::Encrypt,
> -                    ..UploadOptions::default()
> -                };
> -
> -                println!("Upload log file '{}' to '{}' as {}", filename, repo, target);
> -                let stats = client
> -                    .upload_blob_from_file(&filename, &target, upload_options)
> -                    .await?;
> -                manifest.add_file(target, stats.size, stats.csum, crypto.mode)?;
> -            }
> -            BackupSpecificationType::PXAR => {
> -                // start catalog upload on first use
> -                if catalog.is_none() {
> -                    let catalog_upload_res = spawn_catalog_upload(client.clone(), crypto.mode == CryptMode::Encrypt)?;
> -                    catalog = Some(catalog_upload_res.catalog_writer);
> -                    catalog_result_rx = Some(catalog_upload_res.result);
> +        if dry_run {
> +            match backup_type {
> +                BackupSpecificationType::CONFIG => {
> +                    println!("Would upload config file'{}' to '{}' as {}", filename, repo, target);

please factor above print out in a local closure/helper-fn, besides reducing repetition
it would also avoid on having inconsistencies like missing a whitespace after "file" ;-)