wip: parsing cron

Cargo.lock

@@ -17,6 +17,15 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f26201604c87b1e01bd3d98f8d5d9a8fcbb815e8cedb41ffccbeb4bf593a35fe"
 
+[[package]]
+name = "aho-corasick"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b2969dcb958b36655471fc61f7e416fa76033bdd4bfed0678d8fee1e2d07a1f0"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.1.0"
@@ -95,6 +104,12 @@ version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d77f7ec81a6d05a3abb01ab6eb7590f6083d08449fe5a1c8b1e620283546ccb7"
 
+[[package]]
+name = "lazy_static"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+
 [[package]]
 name = "libc"
 version = "0.2.150"
@@ -223,6 +238,35 @@ dependencies = [
  "bitflags 1.3.2",
 ]
 
+[[package]]
+name = "regex"
+version = "1.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "380b951a9c5e80ddfd6136919eef32310721aa4aacd4889a8d39124b026ab343"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5f804c7828047e88b2d32e2d7fe5a105da8ee3264f01902f796c8e067dc2483f"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c08c74e62047bb2de4ff487b251e4a92e24f48745648451635cec7d591162d9f"
+
 [[package]]
 name = "rustc-demangle"
 version = "0.1.23"
@@ -396,7 +440,9 @@ checksum = "ed94fce61571a4006852b7389a063ab983c02eb1bb37b47f8272ce92d06d9538"
 name = "wingmate-rs"
 version = "0.1.0"
 dependencies = [
+ "lazy_static",
  "nix",
+ "regex",
  "tokio",
  "tokio-util",
 ]

Cargo.toml

@@ -6,6 +6,8 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+lazy_static = "1.4.0"
 nix = {version = "0.27.1", features = ["process", "signal", "fs"]}
+regex = "1.10.2"
 tokio = { version = "1.34.0", features = ["full"] }
 tokio-util = "0.7.10"

src/init/config.rs

@@ -1,9 +1,11 @@
 use std::fs;
 use std::path::PathBuf;
-use std::io::{self, BufReader, BufRead};
+use std::io::{BufReader, BufRead};
 use std::error as std_error;
 use crate::init::error as wingmate_error;
 use nix::unistd::{access, AccessFlags};
+use lazy_static::lazy_static;
+use regex::Regex;
 
 #[derive(Debug)]
 pub enum Command {
@@ -15,6 +17,7 @@ pub enum Command {
 pub enum CronTimeFieldSpec {
     Any,
     Exact(u8),
+    MultiOccurrence(Vec<u8>),
     Every(u8)
 }
 
@@ -61,16 +64,8 @@ impl Config {
                         }
                     }
 
-                    // let cron = buf.join("cron");
-                    // if let Ok(cron_iter) = fs::read_dir(cron.as_path()) {
-                    //     for entry in cron_iter {
-                    //         if let Ok(_dirent) = entry {
-                    //             // read the cron file
-                    //         }
-                    //     }
-                    // }
-                    if let Ok(_crontab) = read_crontab(&mut buf) {
-
+                    if let Ok(_crontab) = Self::read_crontab(&mut buf) {
+                        //TODO: fix me! empty branch
                     }
                 } else {
                     // reserve for future use; when we have a centralized config file
@@ -85,16 +80,56 @@ impl Config {
         let config = Config { services: svc_commands };
         Ok(config)
     }
-}
 
     fn read_crontab(path: &mut PathBuf) -> Result<Vec<Crontab>, Box<dyn std_error::Error>> {
+        lazy_static! {
+            static ref CRON_REGEX: Regex = Regex::new(
+                r"^\s*(?P<minute>\S+)\s+(?P<hour>\S+)\s+(?P<dom>\S+)\s+(?P<month>\S+)\s+(?P<dow>\S+)\s+(?P<command>\S.*\S)\s*$"
+            ).unwrap();
+        }
+
         let cron_path = path.join("crontab");
     
         {
             let f = fs::File::open(cron_path.as_path())?;
-        let _line_iter = BufReader::new(f).lines();
+            for line in BufReader::new(f).lines() {
+                if let Ok(l) = line {
+                    let cap = CRON_REGEX.captures(&l).ok_or::<Box<dyn std_error::Error>>(wingmate_error::CronSyntaxError(String::from(&l)).into())?;
+                    
+                    let mut match_str = cap.name("minute").ok_or::<Box<dyn std_error::Error>>(wingmate_error::CronSyntaxError(String::from("cannot capture minute")).into())?;
+                    let _minute = Self::to_cron_time_field_spec(&match_str)?;
+
+                    match_str = cap.name("hour").ok_or::<Box<dyn std_error::Error>>(wingmate_error::CronSyntaxError(String::from("cannot capture hour")).into())?;
+                    let _hour = Self::to_cron_time_field_spec(&match_str)?;
+                }
+            }
         }
         
     
         Err(wingmate_error::NoServiceOrCronFoundError.into())
     }
+
+    fn to_cron_time_field_spec(match_str: &regex::Match) -> Result<CronTimeFieldSpec, Box<dyn std_error::Error>> {
+        let field = match_str.as_str();
+
+        if field == "*" {
+            return Ok(CronTimeFieldSpec::Any);
+        } else if field.starts_with("*/") {
+            let every = field[2..].parse::<u8>()?;
+            return Ok(CronTimeFieldSpec::Every(every));
+        } else if field.contains(",") {
+            let multi: Vec<&str> = field.split(",").collect();
+            let mut multi_occurrence: Vec<u8> = Vec::new();
+
+            for m in multi {
+                let ur = m.parse::<u8>()?;
+                multi_occurrence.push(ur);
+            }
+
+            return Ok(CronTimeFieldSpec::MultiOccurrence(multi_occurrence));
+        } else {
+            let n = field.parse::<u8>()?;
+            return Ok(CronTimeFieldSpec::Exact(n));
+        }
+    }
+}

src/init/error.rs

@@ -23,3 +23,14 @@ impl fmt::Display for NoServiceOrCronFoundError {
 }
 
 impl error::Error for NoServiceOrCronFoundError {}
+
+#[derive(Debug)]
+pub struct CronSyntaxError(pub String);
+
+impl fmt::Display for CronSyntaxError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "cron syntax error at: {}", self.0)
+    }
+}
+
+impl error::Error for CronSyntaxError {}