refactor: use xml for state artifacts instead of json

Author: ra0x3

Cargo.lock

@@ -29,6 +29,7 @@ nix = { version = "0.29", features = ["process", "signal", "user", "sched", "res
 regex = "1.7"
 reqwest = { version = "0.11", features = ["blocking"] }
 serde = { version = "1.0", features = ["derive"] }
+serde-xml-rs = "0.6"
 serde_json = "1.0"
 serde_yaml = "0.9"
 sha2 = "0.10"

Cargo.toml

@@ -19,26 +19,31 @@ Runtime files systemg uses to track services.
 ├── sysg.pid           # Supervisor PID
 ├── control.sock       # Unix socket for IPC
 ├── config_hint        # Last config path
-├── pid.json          # Service → PID mapping
-├── state.json        # Service metadata
+├── pid.xml           # Service → PID mapping
+├── state.xml         # Service metadata
 └── logs/             # Service output
 ```
 
 ## Key files
 
-### pid.json
+### pid.xml
 
 Maps services to process IDs:
 
-```json
-{"services": {"web": 67235, "db": 67236}}
+```xml
+<PidFile>
+  <services>
+    <web>67235</web>
+    <db>67236</db>
+  </services>
+</PidFile>
 ```
 
 ### config_hint
 
 Stores the last config path so you don't need `--config` on every command.
 
-### state.json
+### state.xml
 
 Tracks service status, restart counts, and exit codes.
 

docs/docs/how-it-works/state.md

@@ -106,14 +106,14 @@ impl Ord for DaemonLock {
 
 /// Name of the PID file stored in the state directory.
 /// Contains mappings of service names to process IDs.
-pub const PID_FILE_NAME: &str = "pid.json";
+pub const PID_FILE_NAME: &str = "pid.xml";
 
 /// Lock file suffix for PID file to ensure exclusive access.
 pub const PID_LOCK_SUFFIX: &str = ".lock";
 
 /// Name of the service state file stored in the state directory.
 /// Contains the current state and metadata for all managed services.
-pub const STATE_FILE_NAME: &str = "state.json";
+pub const STATE_FILE_NAME: &str = "state.xml";
 
 // ============================================================================
 // Shell Execution Constants

src/constants.rs

@@ -12,6 +12,7 @@ use chrono::{Local, Utc};
 use chrono_tz::Tz;
 use cron::Schedule;
 use serde::{Deserialize, Serialize};
+use serde_xml_rs;
 use tracing::{debug, info, warn};
 
 use crate::{
@@ -472,7 +473,7 @@ pub struct CronStateFile {
 impl CronStateFile {
     /// Returns the path to the cron state file.
     fn path() -> PathBuf {
-        runtime::state_dir().join("cron_state.json")
+        runtime::state_dir().join("cron_state.xml")
     }
 
     /// Saves the cron state to disk.
@@ -481,7 +482,7 @@ impl CronStateFile {
         if let Some(parent) = path.parent() {
             fs::create_dir_all(parent)?;
         }
-        let data = serde_json::to_string_pretty(self).map_err(std::io::Error::other)?;
+        let data = serde_xml_rs::to_string(self).map_err(std::io::Error::other)?;
 
         use std::io::Write;
         let mut file = fs::File::create(&path)?;
@@ -498,7 +499,7 @@ impl CronStateFile {
         }
 
         let raw = fs::read_to_string(path)?;
-        let state = serde_json::from_str(&raw)
+        let state = serde_xml_rs::from_str(&raw)
             .map_err(|err| std::io::Error::new(std::io::ErrorKind::InvalidData, err))?;
         Ok(state)
     }

src/cron.rs

@@ -20,6 +20,7 @@ use std::{
 use fs2::FileExt;
 use reqwest::blocking::Client;
 use serde::{Deserialize, Serialize, de::Error as _};
+use serde_xml_rs;
 use serde_yaml;
 use sysinfo::{ProcessesToUpdate, System};
 use tracing::{debug, error, info, trace, warn};
@@ -179,7 +180,7 @@ impl PidFile {
             return Ok(Self::default());
         }
         let contents = fs::read_to_string(path)?;
-        let pid_data = serde_json::from_str::<Self>(&contents)?;
+        let pid_data = serde_xml_rs::from_str::<Self>(&contents)?;
         Ok(pid_data)
     }
 
@@ -199,7 +200,7 @@ impl PidFile {
 
         let path = Self::path();
         let contents = fs::read_to_string(&path)?;
-        let pid_data = serde_json::from_str::<Self>(&contents)?;
+        let pid_data = serde_xml_rs::from_str::<Self>(&contents)?;
         Ok(pid_data)
     }
 
@@ -209,7 +210,7 @@ impl PidFile {
 
         let path = Self::path();
         fs::create_dir_all(path.parent().unwrap())?;
-        fs::write(&path, serde_json::to_string_pretty(self)?)?;
+        fs::write(&path, serde_xml_rs::to_string(self)?)?;
         Ok(())
     }
 
@@ -230,7 +231,7 @@ impl PidFile {
         let path = Self::path();
         if path.exists() {
             let contents = fs::read_to_string(&path)?;
-            *self = serde_json::from_str::<Self>(&contents)?;
+            *self = serde_xml_rs::from_str::<Self>(&contents)?;
         }
 
         self.services.insert(service.to_string(), pid);
@@ -239,7 +240,7 @@ impl PidFile {
         }
 
         fs::create_dir_all(path.parent().unwrap())?;
-        fs::write(&path, serde_json::to_string_pretty(self)?)?;
+        fs::write(&path, serde_xml_rs::to_string(self)?)?;
         Ok(())
     }
 
@@ -250,15 +251,15 @@ impl PidFile {
         let path = Self::path();
         if path.exists() {
             let contents = fs::read_to_string(&path)?;
-            *self = serde_json::from_str::<Self>(&contents)?;
+            *self = serde_xml_rs::from_str::<Self>(&contents)?;
         }
 
         if self.services.remove(service).is_none() {
             return Err(PidFileError::ServiceNotFound);
         }
 
         fs::create_dir_all(path.parent().unwrap())?;
-        fs::write(&path, serde_json::to_string_pretty(self)?)?;
+        fs::write(&path, serde_xml_rs::to_string(self)?)?;
         Ok(())
     }
 
@@ -269,15 +270,15 @@ impl PidFile {
         let path = Self::path();
         if path.exists() {
             let contents = fs::read_to_string(&path)?;
-            *self = serde_json::from_str::<Self>(&contents)?;
+            *self = serde_xml_rs::from_str::<Self>(&contents)?;
         }
 
         if self.services.remove(service).is_none() {
             return Err(PidFileError::ServiceNotFound);
         }
         self.service_groups.remove(service);
         fs::create_dir_all(path.parent().unwrap())?;
-        fs::write(&path, serde_json::to_string_pretty(self)?)?;
+        fs::write(&path, serde_xml_rs::to_string(self)?)?;
         Ok(())
     }
 
@@ -296,7 +297,7 @@ impl PidFile {
         let path = Self::path();
         if path.exists() {
             let contents = fs::read_to_string(&path)?;
-            *self = serde_json::from_str::<Self>(&contents)?;
+            *self = serde_xml_rs::from_str::<Self>(&contents)?;
         }
 
         let child_pid = metadata.pid;
@@ -312,7 +313,7 @@ impl PidFile {
         self.spawn_metadata.insert(child_pid, metadata);
 
         fs::create_dir_all(path.parent().unwrap())?;
-        fs::write(&path, serde_json::to_string_pretty(self)?)?;
+        fs::write(&path, serde_xml_rs::to_string(self)?)?;
         Ok(())
     }
 
@@ -326,15 +327,15 @@ impl PidFile {
         let path = Self::path();
         if path.exists() {
             let contents = fs::read_to_string(&path)?;
-            *self = serde_json::from_str::<Self>(&contents)?;
+            *self = serde_xml_rs::from_str::<Self>(&contents)?;
         }
 
         if let Some(metadata) = self.spawn_metadata.get_mut(&child_pid) {
             metadata.last_exit = Some(exit.clone());
         }
 
         fs::create_dir_all(path.parent().unwrap())?;
-        fs::write(&path, serde_json::to_string_pretty(self)?)?;
+        fs::write(&path, serde_xml_rs::to_string(self)?)?;
         Ok(())
     }
 
@@ -345,7 +346,7 @@ impl PidFile {
         let path = Self::path();
         if path.exists() {
             let contents = fs::read_to_string(&path)?;
-            *self = serde_json::from_str::<Self>(&contents)?;
+            *self = serde_xml_rs::from_str::<Self>(&contents)?;
         }
 
         if let Some(parent_pid) = self.parent_map.remove(&child_pid)
@@ -360,7 +361,7 @@ impl PidFile {
         self.spawn_metadata.remove(&child_pid);
 
         fs::create_dir_all(path.parent().unwrap())?;
-        fs::write(&path, serde_json::to_string_pretty(self)?)?;
+        fs::write(&path, serde_xml_rs::to_string(self)?)?;
         Ok(())
     }
 
@@ -373,13 +374,13 @@ impl PidFile {
         let path = Self::path();
         if path.exists() {
             let contents = fs::read_to_string(&path)?;
-            *self = serde_json::from_str::<Self>(&contents)?;
+            *self = serde_xml_rs::from_str::<Self>(&contents)?;
         }
 
         let removed = self.remove_spawn_subtree_in_memory(root_pid);
 
         fs::create_dir_all(path.parent().unwrap())?;
-        fs::write(&path, serde_json::to_string_pretty(self)?)?;
+        fs::write(&path, serde_xml_rs::to_string(self)?)?;
 
         Ok(removed)
     }
@@ -616,7 +617,7 @@ impl ServiceStateFile {
         }
 
         let contents = fs::read_to_string(path)?;
-        let state = serde_json::from_str::<Self>(&contents)?;
+        let state = serde_xml_rs::from_str::<Self>(&contents)?;
         Ok(state)
     }
 
@@ -626,7 +627,7 @@ impl ServiceStateFile {
         if let Some(parent) = path.parent() {
             fs::create_dir_all(parent)?;
         }
-        fs::write(&path, serde_json::to_string_pretty(self)?)?;
+        fs::write(&path, serde_xml_rs::to_string(self)?)?;
         Ok(())
     }
 
@@ -2573,13 +2574,14 @@ impl Daemon {
             )))
         })?;
 
-        let state: BlueGreenState = serde_json::from_str(&content).map_err(|source| {
-            ProcessManagerError::ConfigParseError(serde_yaml::Error::custom(format!(
-                "Failed parsing blue/green state '{}': {}",
-                path.display(),
-                source
-            )))
-        })?;
+        let state: BlueGreenState =
+            serde_xml_rs::from_str(&content).map_err(|source| {
+                ProcessManagerError::ConfigParseError(serde_yaml::Error::custom(format!(
+                    "Failed parsing blue/green state '{}': {}",
+                    path.display(),
+                    source
+                )))
+            })?;
 
         if state.active_slot_index > 1 {
             return Err(Self::config_error(format!(
@@ -2602,7 +2604,7 @@ impl Daemon {
         if let Some(parent) = path.parent() {
             fs::create_dir_all(parent)?;
         }
-        let content = serde_json::to_string(&BlueGreenState { active_slot_index })
+        let content = serde_xml_rs::to_string(&BlueGreenState { active_slot_index })
             .map_err(|source| {
                 ProcessManagerError::ConfigParseError(serde_yaml::Error::custom(
                     source.to_string(),

src/daemon.rs

@@ -1,4 +1,5 @@
 //! Error handling for systemg.
+use serde_xml_rs;
 use thiserror::Error;
 
 /// Defines all possible errors that can occur in the process manager.
@@ -145,9 +146,9 @@ pub enum PidFileError {
     #[error("Failed to read PID file: {0}")]
     ReadError(#[from] std::io::Error),
 
-    /// Error writing to a PID file.
+    /// Error parsing XML PID file.
     #[error("Failed to parse PID file: {0}")]
-    ParseError(#[from] serde_json::Error),
+    ParseError(#[from] serde_xml_rs::Error),
 
     /// Error writing to a PID file.
     #[error("Service not found in PID file")]
@@ -161,9 +162,9 @@ pub enum ServiceStateError {
     #[error("Failed to read service state file: {0}")]
     ReadError(#[from] std::io::Error),
 
-    /// Error parsing JSON contents of the state file.
+    /// Error parsing XML contents of the state file.
     #[error("Failed to parse service state file: {0}")]
-    ParseError(#[from] serde_json::Error),
+    ParseError(#[from] serde_xml_rs::Error),
 
     /// Attempted to update or remove a non-existent service entry.
     #[error("Service not found in state file")]