sql-middleware 0.7.0

Lightweight async wrappers for tokio-postgres, rusqlite, turso, and tiberius.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155

use crate::middleware::SqlMiddlewareDbError;

use super::{SqliteConnection, run_blocking};
use crate::sqlite::config::SharedSqliteConnection;
use std::sync::Arc;
use std::thread;
use std::time::Duration;
use tokio::time::sleep;

const ROLLBACK_BUSY_RETRIES: &[Duration] =
    &[Duration::from_millis(10), Duration::from_millis(25), Duration::from_millis(50)];

pub(crate) async fn rollback_with_busy_retries(
    handle: &SharedSqliteConnection,
) -> Result<(), SqlMiddlewareDbError> {
    if handle.force_rollback_busy_for_tests() {
        return Err(SqlMiddlewareDbError::SqliteError(
            rusqlite::Error::SqliteFailure(
                rusqlite::ffi::Error {
                    code: rusqlite::ErrorCode::DatabaseBusy,
                    extended_code: rusqlite::ErrorCode::DatabaseBusy as i32,
                },
                None,
            ),
        ));
    }

    for (idx, delay) in ROLLBACK_BUSY_RETRIES.iter().copied().enumerate() {
        let result = run_blocking(Arc::clone(handle), |guard| {
            guard
                .execute_batch("ROLLBACK")
                .map_err(SqlMiddlewareDbError::SqliteError)
        })
        .await;

        if result.is_ok() {
            return result;
        }
        if let Err(SqlMiddlewareDbError::SqliteError(rusqlite::Error::SqliteFailure(err, _))) =
            &result
            && err.code == rusqlite::ErrorCode::DatabaseBusy
            && idx + 1 < ROLLBACK_BUSY_RETRIES.len()
        {
            sleep(delay).await;
            continue;
        }
        return result;
    }

    Err(SqlMiddlewareDbError::ExecutionError(
        "rollback retries exhausted".into(),
    ))
}

pub(crate) fn rollback_with_busy_retries_blocking(
    handle: &SharedSqliteConnection,
) -> Result<(), SqlMiddlewareDbError> {
    if handle.force_rollback_busy_for_tests() {
        return Err(SqlMiddlewareDbError::SqliteError(
            rusqlite::Error::SqliteFailure(
                rusqlite::ffi::Error {
                    code: rusqlite::ErrorCode::DatabaseBusy,
                    extended_code: rusqlite::ErrorCode::DatabaseBusy as i32,
                },
                None,
            ),
        ));
    }

    for (idx, delay) in ROLLBACK_BUSY_RETRIES.iter().copied().enumerate() {
        let result = handle.execute_blocking(|guard| {
            guard
                .execute_batch("ROLLBACK")
                .map_err(SqlMiddlewareDbError::SqliteError)
        });

        if result.is_ok() {
            return result;
        }
        if let Err(SqlMiddlewareDbError::SqliteError(rusqlite::Error::SqliteFailure(err, _))) =
            &result
            && err.code == rusqlite::ErrorCode::DatabaseBusy
            && idx + 1 < ROLLBACK_BUSY_RETRIES.len()
        {
            thread::sleep(delay);
            continue;
        }
        return result;
    }

    Err(SqlMiddlewareDbError::ExecutionError(
        "rollback retries exhausted".into(),
    ))
}

impl SqliteConnection {
    /// Begin a transaction, transitioning this connection into transactional mode.
    ///
    /// # Errors
    /// Returns `SqlMiddlewareDbError` if the transaction cannot be started or is already active.
    pub async fn begin(&mut self) -> Result<(), SqlMiddlewareDbError> {
        if self.in_transaction {
            return Err(SqlMiddlewareDbError::ExecutionError(
                "SQLite transaction already in progress".into(),
            ));
        }
        run_blocking(self.conn_handle(), move |guard| {
            guard
                .execute_batch("BEGIN")
                .map_err(SqlMiddlewareDbError::SqliteError)
        })
        .await?;
        self.in_transaction = true;
        Ok(())
    }

    /// Commit an open transaction.
    ///
    /// # Errors
    /// Returns `SqlMiddlewareDbError` if committing fails or no transaction is active.
    pub async fn commit(&mut self) -> Result<(), SqlMiddlewareDbError> {
        if !self.in_transaction {
            return Err(SqlMiddlewareDbError::ExecutionError(
                "SQLite transaction not active".into(),
            ));
        }
        run_blocking(self.conn_handle(), move |guard| {
            guard
                .execute_batch("COMMIT")
                .map_err(SqlMiddlewareDbError::SqliteError)
        })
        .await?;
        self.in_transaction = false;
        Ok(())
    }

    /// Roll back an open transaction.
    ///
    /// # Errors
    /// Returns `SqlMiddlewareDbError` if rolling back fails or no transaction is active.
    pub async fn rollback(&mut self) -> Result<(), SqlMiddlewareDbError> {
        if !self.in_transaction {
            return Err(SqlMiddlewareDbError::ExecutionError(
                "SQLite transaction not active".into(),
            ));
        }
        let result = rollback_with_busy_retries(&self.conn_handle()).await;
        if result.is_err() {
            self.mark_broken();
            return result;
        }
        self.in_transaction = false;
        result
    }
}