persistant_sqlx/
lib.rs

1// SPDX-License-Identifier: MIT OR Apache-2.0
2//! PersistAnt's relational driver over sqlx (PostgreSQL first).
3//!
4//! [`PgBackend`] implements [`persistant_relational::RelationalBackend`]. The concrete
5//! [`sqlx::PgPool`] is available through [`PgBackend::pool`], so a program that wants
6//! compile-time-checked `sqlx::query!` keeps it (D1, C+): this crate does not hide sqlx.
7//!
8//! Failures are classified from the server's SQLSTATE into [`persistant_relational::RelError`].
9
10mod bounded;
11#[cfg(feature = "bridge")]
12mod bridge;
13mod decode;
14mod migrate;
15#[cfg(feature = "mysql")]
16mod mysql;
17mod options;
18#[cfg(feature = "sqlite")]
19mod sqlite;
20
21pub use bounded::{Bounded, BoundedTx, call_bound_from_env, parse_bound};
22#[cfg(feature = "bridge")]
23pub use bridge::{OnConn, OnPool};
24pub use migrate::{FromSqlxError, migrations_from_sqlx};
25#[cfg(feature = "mysql")]
26pub use mysql::{MysqlBackend, MysqlTx};
27pub use options::{ConnectOptions, TlsPolicy};
28pub use persistant_relational::{MigrateError, MigrateReport, Migrates, Migration};
29#[cfg(feature = "sqlite")]
30pub use sqlite::{SqliteBackend, SqliteTx};
31
32use persistant_relational::{
33    Dialect, Isolation, RelError, RelationalBackend, RelationalTx, Row, Value,
34};
35use sqlx::postgres::{PgArguments, PgPoolOptions, PgRow};
36use sqlx::query::Query;
37use sqlx::{Column, Postgres, Row as SqlxRow, TypeInfo, ValueRef};
38
39/// Classify an sqlx error by SQLSTATE (https://www.postgresql.org/docs/current/errcodes-appendix.html).
40pub(crate) fn classify(e: sqlx::Error) -> RelError {
41    match &e {
42        sqlx::Error::Database(db) => {
43            let constraint = db.constraint().map(str::to_string);
44            match db.code().as_deref() {
45                Some("23505") => RelError::UniqueViolation { constraint },
46                Some("23503") => RelError::ForeignKeyViolation { constraint },
47                Some("23514") | Some("23502") => RelError::CheckViolation { constraint },
48                Some("40001") => RelError::Serialization,
49                Some("40P01") => RelError::Deadlock,
50                Some(c) if c.starts_with("08") || c.starts_with("57P") => {
51                    RelError::Unavailable(e.to_string())
52                }
53                _ => RelError::Backend(e.to_string()),
54            }
55        }
56        sqlx::Error::Io(_) | sqlx::Error::PoolTimedOut | sqlx::Error::PoolClosed => {
57            RelError::Unavailable(e.to_string())
58        }
59        _ => RelError::Backend(e.to_string()),
60    }
61}
62
63/// A `NULL` whose type the server infers from the statement. Binding `Option::<String>::None` sends
64/// the type `text`, which the server rejects for a `bigint` column (`expression is of type text`) the
65/// first time a pooled connection prepares that statement, and not on one that already has: a failure
66/// that depends on which connection the pool hands out. Type OID 0 means "unspecified".
67struct UntypedNull;
68
69impl sqlx::Type<Postgres> for UntypedNull {
70    fn type_info() -> sqlx::postgres::PgTypeInfo {
71        sqlx::postgres::PgTypeInfo::with_oid(sqlx::postgres::types::Oid(0))
72    }
73
74    fn compatible(_: &sqlx::postgres::PgTypeInfo) -> bool {
75        true
76    }
77}
78
79impl<'q> sqlx::Encode<'q, Postgres> for UntypedNull {
80    fn encode_by_ref(
81        &self,
82        _: &mut sqlx::postgres::PgArgumentBuffer,
83    ) -> Result<sqlx::encode::IsNull, sqlx::error::BoxDynError> {
84        Ok(sqlx::encode::IsNull::Yes)
85    }
86}
87
88fn bind<'q>(
89    mut q: Query<'q, Postgres, PgArguments>,
90    params: &'q [Value],
91) -> Result<Query<'q, Postgres, PgArguments>, RelError> {
92    for p in params {
93        q = match p {
94            // A NULL of unspecified type: the server infers it from the statement.
95            Value::Null => q.bind(UntypedNull),
96            Value::Bool(b) => q.bind(*b),
97            Value::Int(n) => q.bind(*n),
98            Value::Float(f) => q.bind(*f),
99            Value::Text(s) => q.bind(s.as_str()),
100            Value::Bytes(b) => q.bind(b.as_slice()),
101            other => {
102                return Err(RelError::Unsupported(format!(
103                    "parameter {other:?} has no PostgreSQL binding in this driver"
104                )));
105            }
106        };
107    }
108    Ok(q)
109}
110
111fn decode_failed(e: sqlx::error::BoxDynError) -> RelError {
112    RelError::Backend(e.to_string())
113}
114
115fn malformed(column: &str, ty: &str, why: String) -> RelError {
116    RelError::Backend(format!("column {column:?} ({ty}): {why}"))
117}
118
119fn decode(row: &PgRow) -> Result<Row, RelError> {
120    let mut values = Vec::with_capacity(row.columns().len());
121    for (i, col) in row.columns().iter().enumerate() {
122        let raw = row.try_get_raw(i).map_err(classify)?;
123        if raw.is_null() {
124            values.push(Value::Null);
125            continue;
126        }
127        let name = col.type_info().name().to_string();
128        let v = match name.as_str() {
129            "BOOL" => Value::Bool(row.try_get::<bool, _>(i).map_err(classify)?),
130            "INT2" => Value::Int(i64::from(row.try_get::<i16, _>(i).map_err(classify)?)),
131            "INT4" => Value::Int(i64::from(row.try_get::<i32, _>(i).map_err(classify)?)),
132            "INT8" => Value::Int(row.try_get::<i64, _>(i).map_err(classify)?),
133            "FLOAT4" => Value::Float(decode::f32_shortest(
134                row.try_get::<f32, _>(i).map_err(classify)?,
135            )),
136            "FLOAT8" => Value::Float(row.try_get::<f64, _>(i).map_err(classify)?),
137            // sqlx names `bpchar` (char(n)) "CHAR"; the quoted "CHAR" is the one-byte internal type.
138            "TEXT" | "VARCHAR" | "NAME" | "BPCHAR" | "CHAR" => {
139                Value::Text(row.try_get::<String, _>(i).map_err(classify)?)
140            }
141            "BYTEA" => Value::Bytes(row.try_get::<Vec<u8>, _>(i).map_err(classify)?),
142            // Types with a canonical text form (`decode.rs`): carried as that text.
143            "UUID" => Value::Text(
144                decode::uuid_text(raw.as_bytes().map_err(decode_failed)?)
145                    .map_err(|m| malformed(col.name(), &name, m))?,
146            ),
147            "NUMERIC" => Value::Text(
148                decode::numeric_text(raw.as_bytes().map_err(decode_failed)?)
149                    .map_err(|m| malformed(col.name(), &name, m))?,
150            ),
151            "INET" | "CIDR" => Value::Text(
152                decode::inet_text(raw.as_bytes().map_err(decode_failed)?)
153                    .map_err(|m| malformed(col.name(), &name, m))?,
154            ),
155            "JSON" => Value::Text(
156                String::from_utf8(raw.as_bytes().map_err(decode_failed)?.to_vec())
157                    .map_err(|e| malformed(col.name(), &name, e.to_string()))?,
158            ),
159            "JSONB" => {
160                // Version byte 1, then the JSON text.
161                let b = raw.as_bytes().map_err(decode_failed)?;
162                match b.split_first() {
163                    Some((1, rest)) => Value::Text(
164                        String::from_utf8(rest.to_vec())
165                            .map_err(|e| malformed(col.name(), &name, e.to_string()))?,
166                    ),
167                    _ => return Err(malformed(col.name(), &name, "unknown jsonb version".into())),
168                }
169            }
170            "DATE" => Value::Text(decode::date_text(
171                row.try_get::<sqlx::types::time::Date, _>(i)
172                    .map_err(classify)?,
173            )),
174            "TIME" => Value::Text(decode::time_text(
175                row.try_get::<sqlx::types::time::Time, _>(i)
176                    .map_err(classify)?,
177            )),
178            "TIMESTAMP" => Value::Text(decode::naive_text(
179                row.try_get::<sqlx::types::time::PrimitiveDateTime, _>(i)
180                    .map_err(classify)?,
181            )),
182            "TIMESTAMPTZ" => Value::Text(decode::utc_text(
183                row.try_get::<sqlx::types::time::OffsetDateTime, _>(i)
184                    .map_err(classify)?,
185            )),
186            other => {
187                return Err(RelError::Unsupported(format!(
188                    "column {:?} has type {other}, which Value cannot carry; use PgBackend::pool",
189                    col.name()
190                )));
191            }
192        };
193        values.push(v);
194    }
195    Ok(Row::new(values))
196}
197
198/// A PostgreSQL database behind an sqlx pool.
199#[derive(Debug, Clone)]
200pub struct PgBackend {
201    pool: sqlx::PgPool,
202    version: String,
203}
204
205impl PgBackend {
206    /// Connect with default pool settings and read the server version.
207    ///
208    /// Prefer [`PgBackend::connect_secret`]: a `&str` URL is one `Debug` print from a log file.
209    pub async fn connect(url: &str) -> Result<Self, RelError> {
210        let pool = PgPoolOptions::new()
211            .max_connections(16)
212            .connect(url)
213            .await
214            .map_err(classify)?;
215        Self::from_pool(pool).await
216    }
217
218    /// Connect with a connection string held as a [`persistant_relational::ConnectionSecret`]:
219    /// resolved here, never printed, never part of an error.
220    pub async fn connect_secret(
221        secret: &persistant_relational::ConnectionSecret,
222    ) -> Result<Self, RelError> {
223        let url = secret.resolve()?;
224        Self::connect(url.expose()).await
225    }
226
227    /// Wrap an existing pool (a program that already owns one keeps it).
228    pub async fn from_pool(pool: sqlx::PgPool) -> Result<Self, RelError> {
229        let full: String = sqlx::query_scalar("SHOW server_version")
230            .fetch_one(&pool)
231            .await
232            .map_err(classify)?;
233        // "16.15 (Debian 16.15-1.pgdg13+2)" -> "16.15"
234        let version = full.split_whitespace().next().unwrap_or("").to_string();
235        Ok(PgBackend { pool, version })
236    }
237
238    /// The concrete pool: for `sqlx::query!` and anything this layer does not carry.
239    pub fn pool(&self) -> &sqlx::PgPool {
240        &self.pool
241    }
242}
243
244impl RelationalBackend for PgBackend {
245    type Tx<'a> = PgTx<'a>;
246
247    fn backend(&self) -> &str {
248        "postgres"
249    }
250
251    fn version(&self) -> &str {
252        &self.version
253    }
254
255    fn dialect(&self) -> Dialect {
256        Dialect::Postgres
257    }
258
259    async fn execute(&self, sql: &str, params: &[Value]) -> Result<u64, RelError> {
260        let q = bind(sqlx::query(sqlx::AssertSqlSafe(sql.to_string())), params)?;
261        q.execute(&self.pool)
262            .await
263            .map(|r| r.rows_affected())
264            .map_err(classify)
265    }
266
267    async fn query(&self, sql: &str, params: &[Value]) -> Result<Vec<Row>, RelError> {
268        let q = bind(sqlx::query(sqlx::AssertSqlSafe(sql.to_string())), params)?;
269        let rows = q.fetch_all(&self.pool).await.map_err(classify)?;
270        rows.iter().map(decode).collect()
271    }
272
273    async fn begin(&self, isolation: Isolation) -> Result<PgTx<'_>, RelError> {
274        let statement = match isolation {
275            Isolation::ReadCommitted => "BEGIN",
276            Isolation::RepeatableRead => "BEGIN ISOLATION LEVEL REPEATABLE READ",
277            Isolation::Serializable => "BEGIN ISOLATION LEVEL SERIALIZABLE",
278            other => return Err(RelError::Unsupported(format!("isolation level {other:?}"))),
279        };
280        Ok(PgTx {
281            tx: self.pool.begin_with(statement).await.map_err(classify)?,
282        })
283    }
284}
285
286/// A PostgreSQL transaction.
287#[derive(Debug)]
288pub struct PgTx<'a> {
289    tx: sqlx::Transaction<'a, Postgres>,
290}
291
292impl RelationalTx for PgTx<'_> {
293    async fn execute(&mut self, sql: &str, params: &[Value]) -> Result<u64, RelError> {
294        let q = bind(sqlx::query(sqlx::AssertSqlSafe(sql.to_string())), params)?;
295        q.execute(&mut *self.tx)
296            .await
297            .map(|r| r.rows_affected())
298            .map_err(classify)
299    }
300
301    async fn query(&mut self, sql: &str, params: &[Value]) -> Result<Vec<Row>, RelError> {
302        let q = bind(sqlx::query(sqlx::AssertSqlSafe(sql.to_string())), params)?;
303        let rows = q.fetch_all(&mut *self.tx).await.map_err(classify)?;
304        rows.iter().map(decode).collect()
305    }
306
307    async fn commit(self) -> Result<(), RelError> {
308        self.tx.commit().await.map_err(classify)
309    }
310
311    async fn rollback(self) -> Result<(), RelError> {
312        self.tx.rollback().await.map_err(classify)
313    }
314}
persistant_sqlx/lib.rs

persistant_sqlx/
lib.rs
