Add script extension

src/extension/mod.rs

@@ -2,6 +2,7 @@ use serde_yaml::Mapping;
 
 mod date;
 mod shell;
+mod script;
 
 pub trait Extension {
     fn name(&self) -> String;
@@ -12,5 +13,6 @@ pub fn get_extensions() -> Vec<Box<dyn Extension>> {
     vec![
         Box::new(date::DateExtension::new()),
         Box::new(shell::ShellExtension::new()),
+        Box::new(script::ScriptExtension::new()),
     ]
 }

src/extension/script.rs

@@ -0,0 +1,55 @@
+use serde_yaml::{Mapping, Value};
+use std::process::Command;
+use log::{warn, error};
+
+pub struct ScriptExtension {}
+
+impl ScriptExtension {
+    pub fn new() -> ScriptExtension {
+        ScriptExtension{}
+    }
+}
+
+impl super::Extension for ScriptExtension {
+    fn name(&self) -> String {
+        String::from("script")
+    }
+
+    fn calculate(&self, params: &Mapping) -> Option<String> {
+        let args = params.get(&Value::from("args"));
+        if args.is_none() {
+            warn!("No 'args' parameter specified for script variable");
+            return None
+        }
+        let args = args.unwrap().as_sequence();
+        if let Some(args) = args {
+            let str_args = args.iter().map(|arg| {
+               arg.as_str().unwrap_or_default().to_string()
+            }).collect::<Vec<String>>();
+
+            let output = if str_args.len() > 1 {
+                Command::new(&str_args[0])
+                    .args(&str_args[1..])
+                    .output()
+            }else{
+                Command::new(&str_args[0])
+                    .output()
+            };
+
+            match output {
+                Ok(output) => {
+                    let output_str = String::from_utf8_lossy(output.stdout.as_slice());
+
+                    return Some(output_str.into_owned())
+                },
+                Err(e) => {
+                    error!("Could not execute script '{:?}', error: {}", args, e);
+                    return None
+                },
+            }
+        }
+
+        error!("Could not execute script with args '{:?}'", args);
+        None
+    }
+}