Add Transport.file_exists to clean up the run method for builtin tasks

Cargo.lock

@@ -515,9 +515,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.56"
+version = "1.0.57"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a9802ddde94170d186eeee5005b798d9c159fa970403f1be19976d0cfb939b72"
+checksum = "4211ce9909eb971f111059df92c45640aad50a619cf55cd76476be803c4c68e6"
 dependencies = [
  "proc-macro2",
  "quote",

model/src/lib.rs

@@ -4,6 +4,7 @@ extern crate pest;
 extern crate pest_derive;
 
 use std::collections::HashMap;
+use std::path::PathBuf;
 
 pub mod inventory;
 pub mod plan;
@@ -13,7 +14,7 @@ pub mod transport;
 
 pub use crate::plan::Plan;
 pub use crate::task::Task;
-pub use crate::transport::Transport;
+pub use crate::transport::{Transport, TransportError};
 
 /**
  * An ExecutableTask is a light container over a Task execpt with user-provided information and is
@@ -29,4 +30,16 @@ impl ExecutableTask {
     pub fn new(task: Task, parameters: HashMap<String, String>) -> Self {
         Self { task, parameters }
     }
+
+    /**
+     * Provides will return the files that the ExecutableTask provides
+     *
+     * If these files exist, the task should not be executed
+     */
+    pub fn provides() -> Vec<PathBuf> {
+        vec![]
+    }
 }
+
+#[cfg(test)]
+mod tests {}

model/src/transport/mod.rs

@@ -5,6 +5,10 @@ use std::path::Path;
 
 pub mod ssh;
 
+pub enum TransportError {
+    GeneralError(String),
+}
+
 /**
  * The Transport trait allows for multiple transports to be implemented for
  * connecting to targets
@@ -12,6 +16,8 @@ pub mod ssh;
 pub trait Transport {
     fn connect(&mut self, target: &Target) -> bool;
     fn disconnect(&mut self);
+    fn file_exists(&self, path: &Path) -> Result<bool, TransportError>;
+    fn run(&mut self, command: &ExecutableTask, target: &Target, dry_run: bool) -> i32;
     fn run_group(
         &mut self,
         cmd: &ExecutableTask,
@@ -19,6 +25,5 @@ pub trait Transport {
         inv: &Inventory,
         dry_run: bool,
     ) -> i32;
-    fn run(&mut self, command: &ExecutableTask, target: &Target, dry_run: bool) -> i32;
     fn send_bytes(&self, remote_path: &Path, bytes: &Vec<u8>, mode: i32) -> bool;
 }

model/src/transport/ssh.rs

@@ -1,6 +1,6 @@
 use crate::inventory::{Group, Inventory, Target};
 use crate::transport::Transport;
-use crate::ExecutableTask;
+use crate::{ExecutableTask, TransportError};
 
 use colored::*;
 
@@ -90,6 +90,28 @@ impl Transport for Ssh {
         true
     }
 
+    fn file_exists(&self, path: &Path) -> Result<bool, TransportError> {
+        if let Err(error) = self.session.scp_recv(path) {
+            if error.code() == ssh2::ErrorCode::Session(-28) {
+                debug!("The file ({}) does not exist", path.display());
+            } else {
+                error!(
+                    "A failure occurred while trying to check a file exists: {:?}",
+                    error
+                );
+                return Err(TransportError::GeneralError(
+                    "Failed to check that file exists".into(),
+                ));
+            }
+        } else {
+            // If we successfully fetched the provided file, then we should
+            // return 0 and skip the function
+            trace!("The file exists: {}", path.display());
+            return Ok(true);
+        }
+        return Ok(false);
+    }
+
     fn run(&mut self, command: &ExecutableTask, target: &Target, dry_run: bool) -> i32 {
         if !self.connect(target) {
             error!("Failed to connect to {:?}", target);
@@ -102,27 +124,13 @@ impl Transport for Ssh {
                 provides
             );
 
-            if let Err(error) = self.session.scp_recv(&Path::new(&provides)) {
-                if error.code() == ssh2::ErrorCode::Session(-28) {
-                    debug!(
-                        "The provided file ({}) does not exist, the command should be run",
-                        provides
-                    );
-                } else {
-                    error!(
-                        "A failure occurred while trying to check the provided file: {:?}",
-                        error
-                    );
-                    return -1;
+            if let Ok(found) = self.file_exists(Path::new(provides)) {
+                if found {
+                    debug!("File {} exists, skipping task", provides);
+                    return 0;
                 }
             } else {
-                // If we successfully fetched the provided file, then we should
-                // return 0 and skip the function
-                debug!(
-                    "The provided file ({}) was found, avoiding re-running",
-                    provides
-                );
-                return 0;
+                return -1;
             }
         }