Tidy command execution

src/command.rs

@@ -6,7 +6,12 @@ pub trait Filter {
     fn filter(&self, reader: Box<dyn Read>) -> Box<dyn Read>;
 }
 
-pub fn exec_command(command: &Vec<&str>) -> Result<String, String> {
+// TODO: Make this support quoting for args with spaces (and escape nested quotes)
+fn display_command(command: &Vec<&str>) -> String {
+    command.join(" ")
+}
+
+pub fn exec(command: &Vec<&str>) -> Result<String, String> {
     if command.is_empty() {
         return Err("Command is empty".to_string());
     }
@@ -14,11 +19,13 @@ pub fn exec_command(command: &Vec<&str>) -> Result<String, String> {
     if command.len() > 1 {
         cmd.args(&command[1..]);
     }
-    let output = cmd.output().map_err(|e| e.to_string())?;
+    let output = cmd
+        .output()
+        .map_err(|e| format!("Failed to run command {}: {}", command[0], e))?;
     if !output.status.success() {
         return Err(format!(
-            "Command {:?} failed with status {}: {}",
-            command,
+            "Command '{}' failed with status {}: {}",
+            display_command(command),
             output.status,
             String::from_utf8_lossy(&output.stderr)
         ));
@@ -27,7 +34,10 @@ pub fn exec_command(command: &Vec<&str>) -> Result<String, String> {
     Ok(output_str)
 }
 
-pub fn exec_piped_commands(
+/// Executes a pipeline of commands, where the output of the source command is passed through a
+/// series of filters before being piped into the destination command. The filters are applied in
+/// the order they are provided.
+pub fn exec_pipe(
     source: &Vec<&str>,
     dest: &Vec<&str>,
     filters: Vec<Box<dyn Filter>>,

src/job.rs

@@ -57,7 +57,7 @@ impl Job {
         let name = snapshot.to_string();
         let mut cmd = self.get_side_command(side);
         cmd.extend(["snapshot", &name]);
-        command::exec_command(&cmd)?;
+        command::exec(&cmd)?;
         self.send_event(BackupEvent::SnapshotCreated(name.clone()));
         Ok(snapshot)
     }
@@ -70,7 +70,7 @@ impl Job {
         }
         cmd.extend(["-n", "-P"]);
         cmd.push(source);
-        let output = command::exec_command(&cmd)?;
+        let output = command::exec(&cmd)?;
         let size = output
             .lines()
             .last()
@@ -107,7 +107,7 @@ impl Job {
             ))],
             None => vec![],
         };
-        command::exec_piped_commands(&send_cmd, &receive_cmd, filters)?;
+        command::exec_pipe(&send_cmd, &receive_cmd, filters)?;
         self.send_event(BackupEvent::DatasetCompleted(source.to_string()));
         Ok(())
     }
@@ -115,7 +115,7 @@ impl Job {
     fn list_snapshot_ids(&self, source: &str, side: JobSide) -> Result<Vec<String>, String> {
         let mut cmd = self.get_side_command(side);
         cmd.extend(["list", "-H", "-o", "name", "-t", "snapshot", source]);
-        let output = command::exec_command(&cmd)?;
+        let output = command::exec(&cmd)?;
         let snapshots: Vec<&str> = output
             .split_whitespace()
             .map(|s| {
@@ -195,7 +195,7 @@ impl Job {
         let mut cmd = self.get_side_command(snapshot.side);
         let name = snapshot.to_string();
         cmd.extend(["destroy", &name]);
-        command::exec_command(&cmd)?;
+        command::exec(&cmd)?;
         self.send_event(BackupEvent::SnapshotDeleted(name.clone()));
         Ok(())
     }
@@ -205,7 +205,7 @@ impl Job {
             // Check the source exists
             let mut cmd = self.get_side_command(JobSide::Source);
             cmd.extend(["list", "-H", "-o", "name", source]);
-            let _ = command::exec_command(&cmd)?;
+            let _ = command::exec(&cmd)?;
 
             // Check whether the destination exists
             // TODO: This will assume the destination doesn't exist if the
@@ -213,7 +213,7 @@ impl Job {
             let dest = format!("{}/{}", self.target, source);
             cmd = self.get_side_command(JobSide::Target);
             cmd.extend(["list", "-H", "-o", "name", &dest]);
-            let dest_exists = command::exec_command(&cmd).is_ok();
+            let dest_exists = command::exec(&cmd).is_ok();
 
             // Run backup
             if dest_exists {
@@ -375,7 +375,7 @@ impl JobBuilder {
 
             let mut cmd: Vec<&str> = self.source_zfs_command.iter().map(|s| s.as_str()).collect();
             cmd.extend(args);
-            let output = command::exec_command(&cmd)?;
+            let output = command::exec(&cmd)?;
             datasets.extend(output.lines().map(str::to_string));
         }
         if datasets.is_empty() {