container: change the container status from string to enum

Change the container's status from string type to
enum.

Fixes: #302

Signed-off-by: fupan.lfp <fupan.lfp@antfin.com>

src/agent/rustjail/src/container.rs

@@ -7,6 +7,7 @@ use lazy_static;
 use oci::{Hook, Linux, LinuxNamespace, LinuxResources, POSIXRlimit, Spec};
 use serde_json;
 use std::ffi::{CStr, CString};
+use std::fmt;
 use std::fs;
 use std::os::unix::io::RawFd;
 use std::path::{Path, PathBuf};
@@ -66,20 +67,55 @@ const CWFD_FD: &str = "CWFD_FD";
 const CLOG_FD: &str = "CLOG_FD";
 const FIFO_FD: &str = "FIFO_FD";
 
-type Status = Option<String>;
+#[derive(PartialEq, Clone, Copy)]
+pub enum Status {
+    CREATED,
+    RUNNING,
+    STOPPED,
+    PAUSED,
+}
+
+#[derive(Debug)]
+pub struct ContainerStatus {
+    pre_status: Status,
+    cur_status: Status,
+}
+
+impl ContainerStatus {
+    fn new() -> Self {
+        ContainerStatus {
+            pre_status: Status::CREATED,
+            cur_status: Status::CREATED,
+        }
+    }
+
+    fn status(&self) -> Status {
+        self.cur_status
+    }
+
+    fn pre_status(&self) -> Status {
+        self.pre_status
+    }
+
+    fn transition(&mut self, to: Status) {
+        self.pre_status = self.status();
+        self.cur_status = to;
+    }
+}
+
 pub type Config = CreateOpts;
 type NamespaceType = String;
 
-/*
-impl Status {
-    fn to_string(&self) -> String {
-        match *self {
-            Some(ref v) => v.to_string(),
-            None => "Unknown Status".to_string(),
+impl fmt::Debug for Status {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Status::CREATED => write!(f, "{:?}", "created"),
+            Status::RUNNING => write!(f, "{:?}", "running"),
+            Status::STOPPED => write!(f, "{:?}", "stopped"),
+            Status::PAUSED => write!(f, "{:?}", "paused"),
         }
     }
 }
-*/
 
 lazy_static! {
     static ref NAMESPACES: HashMap<&'static str, CloneFlags> = {
@@ -184,7 +220,7 @@ pub struct BaseState {
 
 pub trait BaseContainer {
     fn id(&self) -> String;
-    fn status(&self) -> Result<Status>;
+    fn status(&self) -> Status;
     fn state(&self) -> Result<State>;
     fn oci_state(&self) -> Result<OCIState>;
     fn config(&self) -> Result<&Config>;
@@ -216,7 +252,7 @@ pub struct LinuxContainer
     pub uid_map_path: String,
     pub gid_map_path: String,
     pub processes: HashMap<pid_t, Process>,
-    pub status: Status,
+    pub status: ContainerStatus,
     pub created: SystemTime,
     pub logger: Logger,
 }
@@ -571,8 +607,8 @@ impl BaseContainer for LinuxContainer {
         self.id.clone()
     }
 
-    fn status(&self) -> Result<Status> {
-        Ok(self.status.clone())
+    fn status(&self) -> Status {
+        self.status.status()
     }
 
     fn state(&self) -> Result<State> {
@@ -581,8 +617,8 @@ impl BaseContainer for LinuxContainer {
 
     fn oci_state(&self) -> Result<OCIState> {
         let oci = self.config.spec.as_ref().unwrap();
-        let status = self.status().unwrap().unwrap();
-        let pid = if status != "stopped".to_string() {
+        let status = self.status();
+        let pid = if status != Status::STOPPED {
             self.init_process_pid
         } else {
             0
@@ -594,7 +630,7 @@ impl BaseContainer for LinuxContainer {
         Ok(OCIState {
             version: oci.version.clone(),
             id: self.id(),
-            status,
+            status: format!("{:?}", status),
             pid,
             bundle,
             annotations: oci.annotations.clone(),
@@ -830,7 +866,6 @@ impl BaseContainer for LinuxContainer {
 
         info!(logger, "entered namespaces!");
 
-        self.status = Some("created".to_string());
         self.created = SystemTime::now();
 
         // create the pipes for notify process exited
@@ -862,7 +897,7 @@ impl BaseContainer for LinuxContainer {
 
         if init {
             self.exec()?;
-            self.status = Some("running".to_string());
+            self.status.transition(Status::RUNNING);
         }
 
         Ok(())
@@ -884,7 +919,7 @@ impl BaseContainer for LinuxContainer {
             }
         }
 
-        self.status = Some("stopped".to_string());
+        self.status.transition(Status::STOPPED);
         fs::remove_dir_all(&self.root)?;
         Ok(())
     }
@@ -912,7 +947,7 @@ impl BaseContainer for LinuxContainer {
             .unwrap()
             .as_secs();
 
-        self.status = Some("running".to_string());
+        self.status.transition(Status::RUNNING);
         unistd::close(fd)?;
 
         Ok(())
@@ -1252,7 +1287,7 @@ impl LinuxContainer {
             id: id.clone(),
             root,
             cgroup_manager: Some(cgroup_manager),
-            status: Some("stopped".to_string()),
+            status: ContainerStatus::new(),
             uid_map_path: String::from(""),
             gid_map_path: "".to_string(),
             config,
@@ -1560,3 +1595,26 @@ fn execute_hook(logger: &Logger, h: &Hook, st: &OCIState) -> Result<()> {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_status_transtition() {
+        let mut status = ContainerStatus::new();
+        let status_table: [Status; 4] = [
+            Status::CREATED,
+            Status::RUNNING,
+            Status::PAUSED,
+            Status::STOPPED,
+        ];
+
+        for s in status_table.iter() {
+            let pre_status = status.status();
+            status.transition(*s);
+
+            assert_eq!(pre_status, status.pre_status());
+        }
+    }
+}