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kaps: Implement simple OCI container state specification
Signed-off-by: kalil <[email protected]>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,208 @@ | ||
| use crate::{Error, Result}; | ||
| use serde::{Deserialize, Serialize}; | ||
| use std::fs; | ||
| use std::fs::{File, OpenOptions}; | ||
| use std::path::PathBuf; | ||
| use std::sync::{Arc, RwLock}; | ||
|
|
||
| const KAPS_ROOT_PATH: &str = "/var/run/kaps/containers"; | ||
| const OCI_VERSION: &str = "0.2.0"; | ||
| const STATE_FILE: &str = "state.json"; | ||
|
|
||
| /// Container runtime status | ||
| #[derive(Serialize, Deserialize, Debug, PartialEq, Copy, Clone)] | ||
| pub enum Status { | ||
| #[serde(rename = "creating")] | ||
| Creating, | ||
| #[serde(rename = "created")] | ||
| Created, | ||
| #[serde(rename = "running")] | ||
| Running, | ||
| #[serde(rename = "stopped")] | ||
| Stopped, | ||
| } | ||
|
|
||
| impl Default for Status { | ||
| fn default() -> Self { | ||
| Status::Creating | ||
| } | ||
| } | ||
|
|
||
| /// Represent the state of the running container. | ||
| #[derive(Serialize, Deserialize, Debug)] | ||
| pub struct ContainerState { | ||
| id: String, | ||
| /// OCI version. | ||
| oci_version: String, | ||
| /// Runtime state of the container. | ||
| pub status: Arc<RwLock<Status>>, | ||
| /// ID of the container process. | ||
| pub pid: i32, | ||
| /// Path to the bundle. | ||
| bundle: PathBuf, | ||
| } | ||
|
|
||
| impl Default for ContainerState { | ||
| fn default() -> Self { | ||
| ContainerState { | ||
| oci_version: OCI_VERSION.to_string(), | ||
| id: String::default(), | ||
| status: Arc::new(RwLock::new(Status::default())), | ||
| pid: 0, | ||
| bundle: PathBuf::default(), | ||
| } | ||
| } | ||
| } | ||
|
|
||
| impl ContainerState { | ||
| pub fn new(id: &str, bundle_path: &str) -> Result<Self> { | ||
| ContainerState::_new(id, bundle_path, KAPS_ROOT_PATH) | ||
| } | ||
|
|
||
| fn _new(id: &str, bundle_path: &str, container_dir: &str) -> Result<Self> { | ||
| let bundle = PathBuf::from(bundle_path); | ||
| let container_path = PathBuf::from(container_dir).join(id); | ||
|
|
||
| if container_path.as_path().exists() { | ||
| return Err(Error::ContainerExists(format!( | ||
| "A container with the id '{}' already exists", | ||
| id | ||
| ))); | ||
| } | ||
|
|
||
| // create the container directory | ||
| fs::create_dir_all(&container_path).map_err(Error::CreateStateFile)?; | ||
|
|
||
| // create the `state.json` file of the container | ||
| File::create(container_path.join(STATE_FILE)).map_err(Error::CreateStateFile)?; | ||
|
|
||
| let container_state = ContainerState { | ||
| id: id.to_string(), | ||
| bundle, | ||
| ..Default::default() | ||
| }; | ||
|
|
||
| container_state.save(container_dir)?; | ||
|
|
||
| Ok(container_state) | ||
| } | ||
|
|
||
| /// Get the current runtime status of the container. | ||
| /// | ||
| /// As The container status is a RwLock, | ||
| /// calling this function results in acquiring a read lock on the status. | ||
| fn _status(&self) -> Result<Status> { | ||
| let container_status = Arc::clone(&self.status); | ||
| let container_status = container_status | ||
| .read() | ||
| .map_err(|e| Error::StatusLockPoisoned(e.to_string()))?; | ||
|
|
||
| Ok(*container_status) | ||
| } | ||
|
|
||
| /// Save the container state. | ||
| /// | ||
| /// The container state file must already have been created. | ||
| fn save(&self, container_dir: &str) -> Result<()> { | ||
| let container_path = PathBuf::from(container_dir).join(&self.id); | ||
|
|
||
| let file = OpenOptions::new() | ||
| .write(true) | ||
| .truncate(true) | ||
| .open(container_path.join(STATE_FILE)) | ||
| .map_err(Error::OpenStateFile)?; | ||
|
|
||
| serde_json::to_writer_pretty(file, &self).map_err(Error::WriteStateFile) | ||
| } | ||
|
|
||
| /// Update runtime status of container. | ||
| pub fn set_status(&mut self, status: Status) -> Result<()> { | ||
| self._set_status(status, KAPS_ROOT_PATH) | ||
| } | ||
|
|
||
| fn _set_status(&mut self, status: Status, container_dir: &str) -> Result<()> { | ||
| let container_status = Arc::clone(&self.status); | ||
|
|
||
| let mut container_status = container_status | ||
| .write() | ||
| .map_err(|e| Error::StatusLockPoisoned(e.to_string()))?; | ||
|
|
||
| *container_status = status; | ||
| drop(container_status); | ||
|
|
||
| self.save(container_dir) | ||
| } | ||
|
|
||
| /// Remove the container state file. | ||
| pub fn remove(&self) -> Result<()> { | ||
| self._remove(KAPS_ROOT_PATH) | ||
| } | ||
|
|
||
| fn _remove(&self, container_dir: &str) -> Result<()> { | ||
| let container_path = PathBuf::from(container_dir).join(&self.id); | ||
|
|
||
| fs::remove_dir_all(container_path).map_err(Error::RemoveStateFile) | ||
| } | ||
| } | ||
|
|
||
| #[cfg(test)] | ||
| mod tests { | ||
| use super::*; | ||
| use crate::{Error, Result}; | ||
| use std::path::Path; | ||
|
|
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| const KAPS_TEST_ROOT_PATH: &str = "/tmp/kaps"; | ||
|
|
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| #[test] | ||
| fn should_create_state_file() -> Result<()> { | ||
| let container_id = "test1"; | ||
|
|
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| let state = ContainerState::_new(container_id, "fake/path/to/bundle", KAPS_TEST_ROOT_PATH)?; | ||
|
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| assert!(Path::new(KAPS_TEST_ROOT_PATH).join(container_id).exists()); | ||
|
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| let _ = state._remove(KAPS_TEST_ROOT_PATH)?; | ||
|
|
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| Ok(()) | ||
| } | ||
|
|
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| #[test] | ||
| fn should_remove_state_file() -> Result<()> { | ||
| let container_id = "test2"; | ||
|
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| let state = ContainerState::_new(container_id, "fake/path/to/bundle", KAPS_TEST_ROOT_PATH)?; | ||
|
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| let _ = state._remove(KAPS_TEST_ROOT_PATH)?; | ||
|
|
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| assert!(!Path::new(KAPS_TEST_ROOT_PATH).join(container_id).exists()); | ||
|
|
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| Ok(()) | ||
| } | ||
|
|
||
| #[test] | ||
| fn should_update_runtime_status() -> Result<()> { | ||
| let container_id = "test3"; | ||
| let container_path = PathBuf::from(KAPS_TEST_ROOT_PATH).join(container_id); | ||
|
|
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| let mut state = | ||
| ContainerState::_new(container_id, "fake/path/to/bundle", KAPS_TEST_ROOT_PATH)?; | ||
|
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| state._set_status(Status::Stopped, KAPS_TEST_ROOT_PATH)?; | ||
|
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| let file_state = | ||
| fs::read_to_string(container_path.join(STATE_FILE)).map_err(Error::ReadStateFile)?; | ||
|
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| let file_state: ContainerState = | ||
| serde_json::from_str(&file_state).map_err(Error::SerializeError)?; | ||
|
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| let file_status = file_state._status()?; | ||
|
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| let status = state._status()?; | ||
|
|
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| assert_eq!(status, file_status); | ||
|
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| let _ = state._remove(KAPS_TEST_ROOT_PATH)?; | ||
|
|
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| Ok(()) | ||
| } | ||
| } |