tokio_task_scheduler/
error.rs

1//! Error types for the scheduler library
2//! 
3//! This module provides comprehensive error handling for the scheduler,
4//! including specific error types for different failure scenarios and
5//! recovery strategies.
6
7use thiserror::Error;
8use std::time::Duration;
9use chrono;
10
11/// Errors that can occur during scheduler operations
12/// 
13/// This enum represents all possible errors that can occur during
14/// task scheduling, execution, and persistence operations.
15#[derive(Error, Debug, Clone)]
16pub enum SchedulerError {
17    /// Error when a task's execution fails
18    #[error("Task execution failed: {0}")]
19    TaskExecutionFailed(String),
20    
21    /// Error when attempting to operate on a non-existent task
22    #[error("Task with ID {0} not found")]
23    TaskNotFound(String),
24    
25    /// Error when parsing an invalid time format
26    #[error("Invalid time format. Expected format: HH:MM or HH:MM:SS, got {0}")]
27    InvalidTimeFormat(String),
28    
29    /// Error when attempting to create an invalid schedule
30    #[error("Invalid schedule: {0}")]
31    InvalidSchedule(String),
32    
33    /// Error during I/O operations
34    #[error("IO error: {0}")]
35    IoError(String),
36    
37    /// Error when attempting to create a duplicate task
38    #[error("Task already exists: {0}")]
39    TaskAlreadyExists(String),
40    
41    /// Error when maximum retry attempts are exceeded
42    #[error("Max retries ({max_retries}) exceeded for task. Last error: {last_error}")]
43    MaxRetriesExceeded {
44        max_retries: u32,
45        last_error: String,
46    },
47    
48    /// Error when unable to retrieve task status
49    #[error("Failed to retrieve task status")]
50    TaskStatusError,
51
52    /// Error when a scheduling conflict occurs
53    #[error("Scheduling conflict: Task cannot be scheduled at the specified time")]
54    SchedulingConflict,
55    
56    /// Error during persistence operations
57    #[error("Persistence error: {0}")]
58    PersistenceError(String),
59}
60
61impl From<std::io::Error> for SchedulerError {
62    fn from(error: std::io::Error) -> Self {
63        SchedulerError::IoError(error.to_string())
64    }
65}
66
67impl SchedulerError {
68    /// Suggests a recovery strategy based on the error type
69    /// 
70    /// # Returns
71    /// 
72    /// * `Some(RecoveryStrategy)` - A suggested recovery strategy for the error
73    /// * `None` - If no recovery strategy is available for this error type
74    pub fn recovery_strategy(&self) -> Option<RecoveryStrategy> {
75        match self {
76            SchedulerError::TaskExecutionFailed(_) => Some(RecoveryStrategy::Retry),
77            SchedulerError::TaskNotFound(_) => Some(RecoveryStrategy::Skip),
78            SchedulerError::InvalidTimeFormat(_) => Some(RecoveryStrategy::Skip),
79            SchedulerError::MaxRetriesExceeded { .. } => Some(RecoveryStrategy::Abort),
80            SchedulerError::SchedulingConflict => Some(RecoveryStrategy::Pause),
81            _ => None
82        }
83    }
84}
85
86/// Suggested recovery strategies for different error types
87/// 
88/// These strategies provide guidance on how to handle specific error cases
89/// in an automated way.
90#[derive(Debug, Clone, Copy)]
91pub enum RecoveryStrategy {
92    /// Retry the failed operation
93    Retry,
94    /// Skip the failed operation and continue
95    Skip,
96    /// Abort the current operation
97    Abort,
98    /// Pause the scheduler
99    Pause,
100}
101
102/// Error context provides additional information about an error
103/// 
104/// This struct contains metadata about an error occurrence, including
105/// retry delays and context-specific information.
106#[derive(Debug, Clone)]
107pub struct ErrorContext {
108    pub error: SchedulerError,
109    pub timestamp: chrono::DateTime<chrono::Utc>,
110    pub retry_delay: Option<Duration>,
111}
112
113impl ErrorContext {
114    /// Creates a new error context
115    /// 
116    /// # Arguments
117    /// 
118    /// * `error` - The scheduler error to create context for
119    /// 
120    /// # Returns
121    /// 
122    /// A new ErrorContext instance
123    pub fn new(error: SchedulerError) -> Self {
124        Self {
125            error,
126            timestamp: chrono::Utc::now(),
127            retry_delay: None,
128        }
129    }
130
131    /// Sets a retry delay for the error
132    /// 
133    /// # Arguments
134    /// 
135    /// * `delay` - The duration to wait before retrying
136    /// 
137    /// # Returns
138    /// 
139    /// The updated ErrorContext instance
140    pub fn with_retry_delay(mut self, delay: Duration) -> Self {
141        self.retry_delay = Some(delay);
142        self
143    }
144}
tokio_task_scheduler/error.rs

tokio_task_scheduler/
error.rs
