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
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
use crate::acquire::Acquire;
use crate::migrate::{AppliedMigration, Migrate, MigrateError, Migration, MigrationSource};
use std::borrow::Cow;
use std::collections::{HashMap, HashSet};
use std::ops::Deref;
use std::slice;
/// A resolved set of migrations, ready to be run.
///
/// Can be constructed statically using `migrate!()` or at runtime using [`Migrator::new()`].
#[derive(Debug)]
// Forbids `migrate!()` from constructing this:
// #[non_exhaustive]
pub struct Migrator {
// NOTE: these fields are semver-exempt and may be changed or removed in any future version.
// These have to be public for `migrate!()` to be able to initialize them in an implicitly
// const-promotable context. A `const fn` constructor isn't implicitly const-promotable.
#[doc(hidden)]
pub migrations: Cow<'static, [Migration]>,
#[doc(hidden)]
pub ignore_missing: bool,
#[doc(hidden)]
pub locking: bool,
#[doc(hidden)]
pub no_tx: bool,
}
fn validate_applied_migrations(
applied_migrations: &[AppliedMigration],
migrator: &Migrator,
) -> Result<(), MigrateError> {
if migrator.ignore_missing {
return Ok(());
}
let migrations: HashSet<_> = migrator.iter().map(|m| m.version).collect();
for applied_migration in applied_migrations {
if !migrations.contains(&applied_migration.version) {
return Err(MigrateError::VersionMissing(applied_migration.version));
}
}
Ok(())
}
impl Migrator {
#[doc(hidden)]
pub const DEFAULT: Migrator = Migrator {
migrations: Cow::Borrowed(&[]),
ignore_missing: false,
no_tx: false,
locking: true,
};
/// Creates a new instance with the given source.
///
/// # Examples
///
/// ```rust,no_run
/// # use sqlx_core::migrate::MigrateError;
/// # fn main() -> Result<(), MigrateError> {
/// # sqlx::__rt::test_block_on(async move {
/// # use sqlx_core::migrate::Migrator;
/// use std::path::Path;
///
/// // Read migrations from a local folder: ./migrations
/// let m = Migrator::new(Path::new("./migrations")).await?;
/// # Ok(())
/// # })
/// # }
/// ```
/// See [MigrationSource] for details on structure of the `./migrations` directory.
pub async fn new<'s, S>(source: S) -> Result<Self, MigrateError>
where
S: MigrationSource<'s>,
{
Ok(Self {
migrations: Cow::Owned(source.resolve().await.map_err(MigrateError::Source)?),
..Self::DEFAULT
})
}
/// Specify whether applied migrations that are missing from the resolved migrations should be ignored.
pub fn set_ignore_missing(&mut self, ignore_missing: bool) -> &Self {
self.ignore_missing = ignore_missing;
self
}
/// Specify whether or not to lock the database during migration. Defaults to `true`.
///
/// ### Warning
/// Disabling locking can lead to errors or data loss if multiple clients attempt to apply migrations simultaneously
/// without some sort of mutual exclusion.
///
/// This should only be used if the database does not support locking, e.g. CockroachDB which talks the Postgres
/// protocol but does not support advisory locks used by SQLx's migrations support for Postgres.
pub fn set_locking(&mut self, locking: bool) -> &Self {
self.locking = locking;
self
}
/// Get an iterator over all known migrations.
pub fn iter(&self) -> slice::Iter<'_, Migration> {
self.migrations.iter()
}
/// Check if a migration version exists.
pub fn version_exists(&self, version: i64) -> bool {
self.iter().any(|m| m.version == version)
}
/// Run any pending migrations against the database; and, validate previously applied migrations
/// against the current migration source to detect accidental changes in previously-applied migrations.
///
/// # Examples
///
/// ```rust,no_run
/// # use sqlx::migrate::MigrateError;
/// # fn main() -> Result<(), MigrateError> {
/// # sqlx::__rt::test_block_on(async move {
/// use sqlx::migrate::Migrator;
/// use sqlx::sqlite::SqlitePoolOptions;
///
/// let m = Migrator::new(std::path::Path::new("./migrations")).await?;
/// let pool = SqlitePoolOptions::new().connect("sqlite::memory:").await?;
/// m.run(&pool).await
/// # })
/// # }
/// ```
pub async fn run<'a, A>(&self, migrator: A) -> Result<(), MigrateError>
where
A: Acquire<'a>,
<A::Connection as Deref>::Target: Migrate,
{
let mut conn = migrator.acquire().await?;
self.run_direct(&mut *conn).await
}
// Getting around the annoying "implementation of `Acquire` is not general enough" error
#[doc(hidden)]
pub async fn run_direct<C>(&self, conn: &mut C) -> Result<(), MigrateError>
where
C: Migrate,
{
// lock the database for exclusive access by the migrator
if self.locking {
conn.lock().await?;
}
// creates [_migrations] table only if needed
// eventually this will likely migrate previous versions of the table
conn.ensure_migrations_table().await?;
let version = conn.dirty_version().await?;
if let Some(version) = version {
return Err(MigrateError::Dirty(version));
}
let applied_migrations = conn.list_applied_migrations().await?;
validate_applied_migrations(&applied_migrations, self)?;
let applied_migrations: HashMap<_, _> = applied_migrations
.into_iter()
.map(|m| (m.version, m))
.collect();
for migration in self.iter() {
if migration.migration_type.is_down_migration() {
continue;
}
match applied_migrations.get(&migration.version) {
Some(applied_migration) => {
if migration.checksum != applied_migration.checksum {
return Err(MigrateError::VersionMismatch(migration.version));
}
}
None => {
conn.apply(migration).await?;
}
}
}
// unlock the migrator to allow other migrators to run
// but do nothing as we already migrated
if self.locking {
conn.unlock().await?;
}
Ok(())
}
/// Run down migrations against the database until a specific version.
///
/// # Examples
///
/// ```rust,no_run
/// # use sqlx::migrate::MigrateError;
/// # fn main() -> Result<(), MigrateError> {
/// # sqlx::__rt::test_block_on(async move {
/// use sqlx::migrate::Migrator;
/// use sqlx::sqlite::SqlitePoolOptions;
///
/// let m = Migrator::new(std::path::Path::new("./migrations")).await?;
/// let pool = SqlitePoolOptions::new().connect("sqlite::memory:").await?;
/// m.undo(&pool, 4).await
/// # })
/// # }
/// ```
pub async fn undo<'a, A>(&self, migrator: A, target: i64) -> Result<(), MigrateError>
where
A: Acquire<'a>,
<A::Connection as Deref>::Target: Migrate,
{
let mut conn = migrator.acquire().await?;
// lock the database for exclusive access by the migrator
if self.locking {
conn.lock().await?;
}
// creates [_migrations] table only if needed
// eventually this will likely migrate previous versions of the table
conn.ensure_migrations_table().await?;
let version = conn.dirty_version().await?;
if let Some(version) = version {
return Err(MigrateError::Dirty(version));
}
let applied_migrations = conn.list_applied_migrations().await?;
validate_applied_migrations(&applied_migrations, self)?;
let applied_migrations: HashMap<_, _> = applied_migrations
.into_iter()
.map(|m| (m.version, m))
.collect();
for migration in self
.iter()
.rev()
.filter(|m| m.migration_type.is_down_migration())
.filter(|m| applied_migrations.contains_key(&m.version))
.filter(|m| m.version > target)
{
conn.revert(migration).await?;
}
// unlock the migrator to allow other migrators to run
// but do nothing as we already migrated
if self.locking {
conn.unlock().await?;
}
Ok(())
}
}