[pve-devel] [PATCH proxmox-perl-rs] initialize logging when shared library is loaded

[Lukas Wagner]

Before, all calls to the log::* macros did not produce any output.
This commit sets up logging by hooking into module loading/bootstraping
process to call a single exported function `setup_logging`. The function
initializes env_logger with its default settings. The benefit of this
approach is that no changes of client-side Perl code is required.

Signed-off-by: Lukas Wagner <l.wagner at proxmox.com>
---
Not sure if this is the best/cleanest approach for this,
seems to work just fine though.

 Proxmox/Lib/template.pm | 7 +++++++
 common/src/logging.rs   | 8 ++++++++
 common/src/mod.rs       | 1 +
 pmg-rs/Cargo.toml       | 1 +
 pve-rs/Cargo.toml       | 1 +
 5 files changed, 18 insertions(+)
 create mode 100644 common/src/logging.rs

diff --git a/Proxmox/Lib/template.pm b/Proxmox/Lib/template.pm
index d7fbbf3..4942a64 100644
--- a/Proxmox/Lib/template.pm
+++ b/Proxmox/Lib/template.pm
@@ -47,6 +47,13 @@ sub load : prototype($) {
     $data->{$mod_name} = $lib;
     $data->{-current} //= $lib;
     $data->{-package} //= $pkg;
+
+    # Lookup up the 'setup_logger' function and call it.
+    # This sets up 'env_logger' so that 'log::*' can be used from Rust code.
+    my $sym  = DynaLoader::dl_find_symbol($lib, "setup_logging");
+    die "failed to locate 'setup_logging'\n" if !defined $sym;
+    my $setup_logging = DynaLoader::dl_install_xsub("setup_logging", $sym, "src/FIXME.rs");
+    $setup_logging->();
 }
 
 sub bootstrap {
diff --git a/common/src/logging.rs b/common/src/logging.rs
new file mode 100644
index 0000000..772b806
--- /dev/null
+++ b/common/src/logging.rs
@@ -0,0 +1,8 @@
+
+#[no_mangle]
+/// Should be called exactly once
+pub extern "C" fn setup_logging() {
+    if let Err(e) = env_logger::try_init() {
+        eprintln!("could not set up env_logger: {e}")
+    }
+}
diff --git a/common/src/mod.rs b/common/src/mod.rs
index b8b843e..749f494 100644
--- a/common/src/mod.rs
+++ b/common/src/mod.rs
@@ -1,3 +1,4 @@
 pub mod apt;
+pub mod logging;
 mod calendar_event;
 mod subscription;
diff --git a/pmg-rs/Cargo.toml b/pmg-rs/Cargo.toml
index 6800f40..2d9ea29 100644
--- a/pmg-rs/Cargo.toml
+++ b/pmg-rs/Cargo.toml
@@ -20,6 +20,7 @@ crate-type = [ "cdylib" ]
 
 [dependencies]
 anyhow = "1.0"
+env_logger = "0.9"
 hex = "0.4"
 http = "0.2.7"
 libc = "0.2"
diff --git a/pve-rs/Cargo.toml b/pve-rs/Cargo.toml
index aa32aeb..6c921c4 100644
--- a/pve-rs/Cargo.toml
+++ b/pve-rs/Cargo.toml
@@ -18,6 +18,7 @@ crate-type = [ "cdylib" ]
 anyhow = "1.0"
 base32 = "0.4"
 base64 = "0.13"
+env_logger = "0.9"
 hex = "0.4"
 http = "0.2.7"
 libc = "0.2"
-- 
2.30.2