tools/unitctl: unitctl export

* new subcommand for "export" in CLI
* new cmd submodule for exporting config tarballs
* logic to also output to stdout
* README additions
* limitations documented

Signed-off-by: Ava Hahn <a.hahn@f5.com>

tools/unitctl/README.md

@@ -177,6 +177,20 @@ Imported /opt/unit/config/put.json -> /config
 Imported 3 files
 ```
 
+### Export configuration from a running Unit instance
+```
+$ unitctl export -f config.tar
+```
+
+Addtionally, standard out can be used:
+```
+$ unitctl export -f -
+$ unitctl export -f - | tar xf - config.json
+$ unitctl export -f - > config.tar
+```
+
+*Note:* The exported configuration omits certificates.
+
 ### Wait for socket to become available
 ```
 $ unitctl --wait-timeout-seconds=3 --wait-max-tries=4 import /opt/unit/config`

tools/unitctl/unitctl/Cargo.toml

@@ -32,6 +32,7 @@ hyperlocal = "0.8"
 hyper-tls = "0.5"
 tokio = { version = "1.35", features = ["macros"] }
 futures = "0.3"
+tar = "0.4.41"
 
 [package.metadata.deb]
 copyright = "2022, F5"

tools/unitctl/unitctl/src/cmd/mod.rs

@@ -5,3 +5,4 @@ pub(crate) mod import;
 pub(crate) mod instances;
 pub(crate) mod listeners;
 pub(crate) mod status;
+pub(crate) mod save;

tools/unitctl/unitctl/src/cmd/save.rs

@@ -0,0 +1,52 @@
+use crate::unitctl::UnitCtl;
+use crate::wait;
+use crate::UnitctlError;
+use crate::requests::send_empty_body_deserialize_response;
+use unit_client_rs::unit_client::UnitClient;
+use tar::{Builder, Header};
+use std::fs::File;
+use std::io::stdout;
+
+
+pub async fn cmd(
+    cli: &UnitCtl,
+    filename: &String
+) -> Result<(), UnitctlError> {
+    if !filename.ends_with(".tar") {
+        eprintln!("Warning: writing uncompressed tarball to {}", filename);
+    }
+
+    let control_socket = wait::wait_for_socket(cli).await?;
+    let client = UnitClient::new(control_socket);
+
+    let config_res = serde_json::to_string_pretty(
+        &send_empty_body_deserialize_response(&client, "GET", "/config").await?
+    );
+    if let Err(e) = config_res {
+        return Err(UnitctlError::DeserializationError{message: e.to_string()})
+    }
+
+    let current_config = config_res
+        .unwrap()
+        .into_bytes();
+
+    //let current_js_modules = send_empty_body_deserialize_response(&client, "GET", "/js_modules")
+    //    .await?;
+
+    let mut conf_header = Header::new_gnu();
+    conf_header.set_size(current_config.len() as u64);
+    conf_header.set_mode(0o644);
+    conf_header.set_cksum();
+
+    // builder has a different type depending on output
+    if filename == "-" {
+        let mut ar = Builder::new(stdout());
+        ar.append_data(&mut conf_header, "config.json", current_config.as_slice()).unwrap();
+    } else {
+        let file = File::create(filename).unwrap();
+        let mut ar = Builder::new(file);
+        ar.append_data(&mut conf_header, "config.json", current_config.as_slice()).unwrap();
+    }
+
+    Ok(())
+}

tools/unitctl/unitctl/src/main.rs

@@ -8,7 +8,11 @@ extern crate unit_client_rs;
 
 use clap::Parser;
 
-use crate::cmd::{applications, edit, execute as execute_cmd, import, instances, listeners, status};
+use crate::cmd::{
+    applications, edit, execute as execute_cmd,
+    import, instances, listeners, status,
+    save
+};
 use crate::output_format::OutputFormat;
 use crate::unitctl::{Commands, UnitCtl};
 use crate::unitctl_error::UnitctlError;
@@ -46,6 +50,8 @@ async fn main() -> Result<(), UnitctlError> {
         Commands::Status { output_format } => status::cmd(&cli, output_format).await,
 
         Commands::Listeners { output_format } => listeners::cmd(&cli, output_format).await,
+
+        Commands::Export { ref filename } => save::cmd(&cli, filename).await,
     }
     .map_err(|error| {
         eprint_error(&error);

tools/unitctl/unitctl/src/unitctl.rs

@@ -116,6 +116,16 @@ pub(crate) enum Commands {
     },
     #[command(about = "List all configured Unit applications")]
     App(ApplicationArgs),
+
+    #[command(about = "Export the current configuration of UNIT")]
+    Export {
+        #[arg(
+            required = true,
+            short = 'f',
+            help = "tarball filename to save configuration to"
+        )]
+        filename: String
+    },
 }
 
 #[derive(Debug, Args)]