Libguestfs - Aug 2023 - [libnbd PATCH v8 04/10] rust: Make it possible to run examples with a URI

Previously, the examples fetch-first-sector and get-size in
rust/examples only accepted a unix socket as argument. This commit makes
it possible to provide a URI as well.
---
 rust/examples/fetch-first-sector.rs | 15 +++++++++++----
 rust/examples/get-size.rs           | 20 +++++++++++++++-----
 2 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/rust/examples/fetch-first-sector.rs
b/rust/examples/fetch-first-sector.rs
index 9efb47a..b035ccb 100644
--- a/rust/examples/fetch-first-sector.rs
+++ b/rust/examples/fetch-first-sector.rs
@@ -7,6 +7,9 @@
 //!
 //!     nbdkit -U - floppy . \
 //!       --run 'cargo run --example fetch-first-sector -- $unixsocket'
+//! Or with a URI:
+//!     nbdkit -U - floppy . \
+//!       --run 'cargo run --example fetch-first-sector -- $uri'
 //!
 //! The nbdkit floppy plugin creates an MBR disk so the
 //! first sector is the partition table.
@@ -21,11 +24,15 @@ fn main() -> anyhow::Result<()> {
     if args.len() != 2 {
         anyhow::bail!("Usage: {:?} socket", args[0]);
     }
-    let socket = &args[1];
 
-    // Connect to the NBD server over a
-    // Unix domain socket.
-    nbd.connect_unix(socket)?;
+    // Check if the user provided a URI or a unix socket.
+    let socket_or_uri = args[1].to_str().unwrap();
+    if socket_or_uri.contains("://") {
+        nbd.connect_uri(socket_or_uri)?;
+    } else {
+        // Connect to the NBD server over a Unix domain socket.
+        nbd.connect_unix(socket_or_uri)?;
+    }
 
     // Read the first sector synchronously.
     let mut buf = [0; 512];
diff --git a/rust/examples/get-size.rs b/rust/examples/get-size.rs
index 7f31df5..7af8e9f 100644
--- a/rust/examples/get-size.rs
+++ b/rust/examples/get-size.rs
@@ -5,6 +5,12 @@
 //!
 //!     nbdkit -U - memory 1M \
 //!       --run 'cargo run --example get-size -- $unixsocket'
+//! Or with a URI:
+//!     nbdkit -U - memory 1M \
+//!       --run 'cargo run --example get-size -- $uri'
+//!
+//! Or connect over a URI:
+//!     cargo run --example get-size -- nbd://hostname:port
 
 use std::env;
 
@@ -15,15 +21,19 @@ fn main() -> anyhow::Result<()> {
     if args.len() != 2 {
         anyhow::bail!("Usage: {:?} socket", args[0]);
     }
-    let socket = &args[1];
 
-    // Connect to the NBD server over a
-    // Unix domain socket.
-    nbd.connect_unix(socket)?;
+    // Check if the user provided a URI or a unix socket.
+    let socket_or_uri = args[1].to_str().unwrap();
+    if socket_or_uri.contains("://") {
+        nbd.connect_uri(socket_or_uri)?;
+    } else {
+        // Connect to the NBD server over a Unix domain socket.
+        nbd.connect_unix(socket_or_uri)?;
+    }
 
     // Read the size in bytes and print it.
     let size = nbd.get_size()?;
-    println!("{:?}: size = {size} bytes", socket);
+    println!("{:?}: size = {size} bytes", socket_or_uri);
 
     Ok(())
 }
-- 
2.41.0

On Sun, Aug 20, 2023 at 02:16:23PM +0000, Tage Johansson
wrote:
> Previously, the examples fetch-first-sector and get-size in
> rust/examples only accepted a unix socket as argument. This commit makes
> it possible to provide a URI as well.
> ---
>  rust/examples/fetch-first-sector.rs | 15 +++++++++++----
>  rust/examples/get-size.rs           | 20 +++++++++++++++-----
>  2 files changed, 26 insertions(+), 9 deletions(-)
> +++ b/rust/examples/get-size.rs
> @@ -5,6 +5,12 @@
>  //!
>  //!     nbdkit -U - memory 1M \
>  //!       --run 'cargo run --example get-size -- $unixsocket'
> +//! Or with a URI:
> +//!     nbdkit -U - memory 1M \
> +//!       --run 'cargo run --example get-size -- $uri'
As $uri is likely to contain the shell glob character '?', we are best
writing this as 'cargo ... -- "$uri"' to set a good example
about how
to avoid rare file name expansion interference.  I made that change in
place, as well as tweaking ocaml/examples/get_size.ml where you copied
from.

For 1-4,
Reviewed-by: Eric Blake <eblake at redhat.com>

and I've gone ahead and pushed them (55fec56c..e5563c0d), in order to
see the effect on CI.

For the rest of the series, I would like to spend a bit more time
reviewing.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.
Virtualization:  qemu.org | libguestfs.org