Struct Upgrader 

pub struct Upgrader { /* private fields */ }

Upgrade orchestrator with rollback support.

Handles the complete upgrade lifecycle:

1. Validate upgrade (prevent downgrade)
2. Download new binary and signature
3. Verify ML-DSA-65 signature
4. Create backup of current binary
5. Atomic replacement
6. Rollback on failure

Implementations

impl Upgrader

pub fn new() -> Self

Create a new upgrader with the current package version.

pub fn current_version(&self) -> &Version

Get the current version.

pub fn validate_upgrade(&self, info: &UpgradeInfo) -> Result<()>

Validate that the upgrade is allowed (prevents downgrade).

Errors

Returns an error if the target version is older than or equal to current.

pub fn create_backup(&self, current: &Path, rollback_dir: &Path) -> Result<()>

Create a backup of the current binary.

Arguments

• current - Path to the current binary
• rollback_dir - Directory to store the backup

Errors

Returns an error if the backup cannot be created.

pub fn restore_from_backup( &self, current: &Path, rollback_dir: &Path, ) -> Result<()>

Restore binary from backup.

Arguments

• current - Path to restore to
• rollback_dir - Directory containing the backup

Errors

Returns an error if the backup cannot be restored.

pub fn atomic_replace(&self, new_binary: &Path, target: &Path) -> Result<()>

Atomically replace the binary (rename on POSIX).

Preserves file permissions from the original binary.

Arguments

• new_binary - Path to the new binary
• target - Path to replace

Errors

Returns an error if the replacement fails.

pub async fn perform_upgrade( &self, info: &UpgradeInfo, current_binary: &Path, rollback_dir: &Path, ) -> Result<UpgradeResult>

Perform upgrade with rollback support.

This is the main upgrade entry point. It:

1. Validates the upgrade (prevents downgrade)
2. Creates a backup of the current binary
3. Downloads the new binary and signature
4. Verifies the ML-DSA-65 signature
5. Atomically replaces the binary
6. Rolls back on any failure

Arguments

• info - Information about the upgrade to perform
• current_binary - Path to the currently running binary
• rollback_dir - Directory to store backup for rollback

Errors

Returns an error only if both the upgrade AND rollback fail (critical).

Trait Implementations

impl Default for Upgrader

fn default() -> Self

Returns the “default value” for a type.