cloud-hypervisor/vmm/src/migration.rs

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// Copyright © 2020 Intel Corporation
//
// SPDX-License-Identifier: Apache-2.0
use crate::vm::{VmSnapshot, VM_SNAPSHOT_ID};
use anyhow::anyhow;
use std::fs::File;
use std::io::BufReader;
use std::path::PathBuf;
use vm_migration::{MigratableError, Snapshot};
pub const VM_SNAPSHOT_FILE: &str = "vm.json";
pub fn url_to_path(url: &str) -> std::result::Result<PathBuf, MigratableError> {
let path: PathBuf = url
.strip_prefix("file://")
.ok_or_else(|| {
MigratableError::MigrateSend(anyhow!("Could not extract path from URL: {}", url))
})
.map(|s| s.into())?;
if !path.is_dir() {
return Err(MigratableError::MigrateSend(anyhow!(
"Destination is not a directory"
)));
}
Ok(path)
}
pub fn recv_vm_snapshot(source_url: &str) -> std::result::Result<Snapshot, MigratableError> {
let mut vm_snapshot_path = url_to_path(source_url)?;
vm_snapshot_path.push(VM_SNAPSHOT_FILE);
// Try opening the snapshot file
let vm_snapshot_file =
File::open(vm_snapshot_path).map_err(|e| MigratableError::MigrateSend(e.into()))?;
let vm_snapshot_reader = BufReader::new(vm_snapshot_file);
let vm_snapshot = serde_json::from_reader(vm_snapshot_reader)
.map_err(|e| MigratableError::MigrateReceive(e.into()))?;
Ok(vm_snapshot)
}
pub fn get_vm_snapshot(snapshot: &Snapshot) -> std::result::Result<VmSnapshot, MigratableError> {
if let Some(vm_section) = snapshot
.snapshot_data
.get(&format!("{}-section", VM_SNAPSHOT_ID))
{
return serde_json::from_slice(&vm_section.snapshot).map_err(|e| {
MigratableError::Restore(anyhow!("Could not deserialize VM snapshot {}", e))
});
}
Err(MigratableError::Restore(anyhow!(
"Could not find VM config snapshot section"
)))
}