update id/revision to make sense/no dupes, add stderr to the example

gregory.example.toml

@@ -27,15 +27,15 @@ max-threads = 10
   [packages.some-librewolf-dependency]
 
     [packages.some-librewolf-dependency.compilation]
-    id = "1"
-    revision = "2"
+    id = "2"
+    revision = "4"
     threads = 2
     image = "docker.io/library/debian"
-    commands = ["echo hi", "echo helloooooooooo"]
+    commands = ["echo hi", "echo helloooooooooo >&2"]
     volumes = ["other-workspace"]
 
     [packages.some-librewolf-dependency.packaging.fedora]
-    id = "1"
+    id = "3"
     revision = "2"
     threads = 2
     image = "docker.io/library/fedora"

src/logging.rs

@@ -0,0 +1,44 @@
+use crate::errors::Error;
+use std::io::Write;
+use std::{
+    fs::{File, OpenOptions},
+    os::unix::fs::FileExt,
+};
+
+/// The logger for gregory itself - NOT for jobs
+pub(crate) struct Logger {
+    log_file: File,
+}
+
+impl Logger {
+    pub(crate) fn new(path: String) -> Result<Logger, Error> {
+        match OpenOptions::new().append(true).open(path) {
+            Ok(f) => return Ok(Logger { log_file: f }),
+            Err(e) => {
+                return Err(Error::IOError(e));
+            }
+        }
+    }
+
+    /// Log a warning
+    ///
+    /// Fun gregory lore: I originally typo'd this as "Strign" and the linter didn't catch it for some reason
+    pub(crate) fn warning(&mut self, text: String) -> Result<(), Error> {
+        match writeln!(&mut self.log_file, "[WARNING] {}", text) {
+            Ok(_) => return Ok(()),
+            Err(e) => {
+                return Err(Error::IOError(e));
+            }
+        }
+    }
+
+    /// Log an error
+    pub(crate) fn error(&mut self, text: String) -> Result<(), Error> {
+        match writeln!(&mut self.log_file, "[ERROR] {}", text) {
+            Ok(_) => return Ok(()),
+            Err(e) => {
+                return Err(Error::IOError(e));
+            }
+        }
+    }
+}

src/main.rs

@@ -20,6 +20,7 @@ mod cli;
 mod data;
 mod errors;
 mod tests;
+mod logging;
 
 fn main() {
     let cli = Cli::parse();