|
| 1 | +use std::fs; |
| 2 | +use std::path::{Path, PathBuf}; |
| 3 | + |
| 4 | +use anyhow::{anyhow, Context, Result}; |
| 5 | +use rusqlite::{params, Connection, OptionalExtension, Row}; |
| 6 | + |
| 7 | +const SCHEMA: &str = r#" |
| 8 | +CREATE TABLE IF NOT EXISTS changes ( |
| 9 | + change_id INTEGER PRIMARY KEY AUTOINCREMENT, |
| 10 | + table_name TEXT NOT NULL, |
| 11 | + op TEXT NOT NULL, |
| 12 | + id TEXT NOT NULL, |
| 13 | + payload BLOB, |
| 14 | + wal_frame TEXT, |
| 15 | + cursor TEXT, |
| 16 | + created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP, |
| 17 | + acked INTEGER NOT NULL DEFAULT 0 |
| 18 | +); |
| 19 | +
|
| 20 | +CREATE TABLE IF NOT EXISTS state ( |
| 21 | + table_name TEXT PRIMARY KEY, |
| 22 | + last_change_id INTEGER NOT NULL DEFAULT 0, |
| 23 | + last_wal_frame TEXT, |
| 24 | + cursor TEXT, |
| 25 | + updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP |
| 26 | +); |
| 27 | +"#; |
| 28 | + |
| 29 | +#[derive(Debug, Clone, Copy, PartialEq, Eq)] |
| 30 | +pub enum ChangeOperation { |
| 31 | + Insert, |
| 32 | + Update, |
| 33 | + Delete, |
| 34 | +} |
| 35 | + |
| 36 | +impl ChangeOperation { |
| 37 | + pub fn as_str(&self) -> &'static str { |
| 38 | + match self { |
| 39 | + ChangeOperation::Insert => "insert", |
| 40 | + ChangeOperation::Update => "update", |
| 41 | + ChangeOperation::Delete => "delete", |
| 42 | + } |
| 43 | + } |
| 44 | + |
| 45 | + fn from_str(value: &str) -> Result<Self> { |
| 46 | + match value { |
| 47 | + "insert" => Ok(ChangeOperation::Insert), |
| 48 | + "update" => Ok(ChangeOperation::Update), |
| 49 | + "delete" => Ok(ChangeOperation::Delete), |
| 50 | + other => Err(anyhow!("unknown change operation '{other}'")), |
| 51 | + } |
| 52 | + } |
| 53 | +} |
| 54 | + |
| 55 | +#[derive(Debug, Clone, PartialEq, Eq)] |
| 56 | +pub struct NewChange { |
| 57 | + pub table_name: String, |
| 58 | + pub operation: ChangeOperation, |
| 59 | + pub primary_key: String, |
| 60 | + pub payload: Option<Vec<u8>>, |
| 61 | + pub wal_frame: Option<String>, |
| 62 | + pub cursor: Option<String>, |
| 63 | +} |
| 64 | + |
| 65 | +#[derive(Debug, Clone, PartialEq, Eq)] |
| 66 | +pub struct ChangeRecord { |
| 67 | + pub change_id: i64, |
| 68 | + pub table_name: String, |
| 69 | + pub operation: ChangeOperation, |
| 70 | + pub primary_key: String, |
| 71 | + pub payload: Option<Vec<u8>>, |
| 72 | + pub wal_frame: Option<String>, |
| 73 | + pub cursor: Option<String>, |
| 74 | +} |
| 75 | + |
| 76 | +#[derive(Debug, Clone, PartialEq, Eq)] |
| 77 | +pub struct QueueState { |
| 78 | + pub table_name: String, |
| 79 | + pub last_change_id: i64, |
| 80 | + pub last_wal_frame: Option<String>, |
| 81 | + pub cursor: Option<String>, |
| 82 | +} |
| 83 | + |
| 84 | +pub struct ChangeQueue { |
| 85 | + path: PathBuf, |
| 86 | + conn: Connection, |
| 87 | +} |
| 88 | + |
| 89 | +impl ChangeQueue { |
| 90 | + pub fn open(path: impl AsRef<Path>) -> Result<Self> { |
| 91 | + let path = path.as_ref(); |
| 92 | + if let Some(parent) = path.parent() { |
| 93 | + fs::create_dir_all(parent).with_context(|| { |
| 94 | + format!("failed to create queue directory {}", parent.display()) |
| 95 | + })?; |
| 96 | + #[cfg(unix)] |
| 97 | + enforce_dir_perms(parent)?; |
| 98 | + } |
| 99 | + let conn = Connection::open(path) |
| 100 | + .with_context(|| format!("failed to open queue database {}", path.display()))?; |
| 101 | + conn.pragma_update(None, "journal_mode", &"wal").ok(); |
| 102 | + conn.pragma_update(None, "synchronous", &"normal").ok(); |
| 103 | + conn.execute_batch(SCHEMA) |
| 104 | + .context("failed to initialize change queue schema")?; |
| 105 | + Ok(Self { |
| 106 | + path: path.to_path_buf(), |
| 107 | + conn, |
| 108 | + }) |
| 109 | + } |
| 110 | + |
| 111 | + pub fn enqueue(&self, change: &NewChange) -> Result<i64> { |
| 112 | + self.conn.execute( |
| 113 | + "INSERT INTO changes(table_name, op, id, payload, wal_frame, cursor) |
| 114 | + VALUES (?1, ?2, ?3, ?4, ?5, ?6)", |
| 115 | + params![ |
| 116 | + change.table_name, |
| 117 | + change.operation.as_str(), |
| 118 | + change.primary_key, |
| 119 | + change.payload, |
| 120 | + change.wal_frame, |
| 121 | + change.cursor, |
| 122 | + ], |
| 123 | + )?; |
| 124 | + Ok(self.conn.last_insert_rowid()) |
| 125 | + } |
| 126 | + |
| 127 | + pub fn fetch_batch(&self, limit: usize) -> Result<Vec<ChangeRecord>> { |
| 128 | + let mut stmt = self.conn.prepare( |
| 129 | + "SELECT change_id, table_name, op, id, payload, wal_frame, cursor |
| 130 | + FROM changes WHERE acked = 0 ORDER BY change_id ASC LIMIT ?1", |
| 131 | + )?; |
| 132 | + let mut rows = stmt.query([limit as i64])?; |
| 133 | + let mut results = Vec::new(); |
| 134 | + while let Some(row) = rows.next()? { |
| 135 | + results.push(row_to_change(&row)?); |
| 136 | + } |
| 137 | + Ok(results) |
| 138 | + } |
| 139 | + |
| 140 | + pub fn ack_up_to(&self, change_id: i64) -> Result<u64> { |
| 141 | + let updated = self.conn.execute( |
| 142 | + "UPDATE changes SET acked = 1 WHERE change_id <= ?1", |
| 143 | + [change_id], |
| 144 | + )?; |
| 145 | + Ok(updated as u64) |
| 146 | + } |
| 147 | + |
| 148 | + pub fn purge_acked(&self) -> Result<u64> { |
| 149 | + let deleted = self |
| 150 | + .conn |
| 151 | + .execute("DELETE FROM changes WHERE acked = 1", [])?; |
| 152 | + Ok(deleted as u64) |
| 153 | + } |
| 154 | + |
| 155 | + pub fn get_state(&self, table: &str) -> Result<Option<QueueState>> { |
| 156 | + self.conn |
| 157 | + .prepare( |
| 158 | + "SELECT table_name, last_change_id, last_wal_frame, cursor |
| 159 | + FROM state WHERE table_name = ?1", |
| 160 | + )? |
| 161 | + .query_row([table], |row| { |
| 162 | + Ok(QueueState { |
| 163 | + table_name: row.get(0)?, |
| 164 | + last_change_id: row.get(1)?, |
| 165 | + last_wal_frame: row.get(2)?, |
| 166 | + cursor: row.get(3)?, |
| 167 | + }) |
| 168 | + }) |
| 169 | + .optional() |
| 170 | + .map_err(Into::into) |
| 171 | + } |
| 172 | + |
| 173 | + pub fn set_state(&self, state: &QueueState) -> Result<()> { |
| 174 | + self.conn.execute( |
| 175 | + "INSERT INTO state(table_name, last_change_id, last_wal_frame, cursor, updated_at) |
| 176 | + VALUES (?1, ?2, ?3, ?4, CURRENT_TIMESTAMP) |
| 177 | + ON CONFLICT(table_name) DO UPDATE SET |
| 178 | + last_change_id = excluded.last_change_id, |
| 179 | + last_wal_frame = excluded.last_wal_frame, |
| 180 | + cursor = excluded.cursor, |
| 181 | + updated_at = CURRENT_TIMESTAMP", |
| 182 | + params![ |
| 183 | + state.table_name, |
| 184 | + state.last_change_id, |
| 185 | + state.last_wal_frame, |
| 186 | + state.cursor, |
| 187 | + ], |
| 188 | + )?; |
| 189 | + Ok(()) |
| 190 | + } |
| 191 | + |
| 192 | + pub fn path(&self) -> &Path { |
| 193 | + &self.path |
| 194 | + } |
| 195 | +} |
| 196 | + |
| 197 | +fn row_to_change(row: &Row<'_>) -> Result<ChangeRecord> { |
| 198 | + let op_str: String = row.get(2)?; |
| 199 | + Ok(ChangeRecord { |
| 200 | + change_id: row.get(0)?, |
| 201 | + table_name: row.get(1)?, |
| 202 | + operation: ChangeOperation::from_str(&op_str)?, |
| 203 | + primary_key: row.get(3)?, |
| 204 | + payload: row.get(4)?, |
| 205 | + wal_frame: row.get(5)?, |
| 206 | + cursor: row.get(6)?, |
| 207 | + }) |
| 208 | +} |
| 209 | + |
| 210 | +#[cfg(unix)] |
| 211 | +fn enforce_dir_perms(path: &Path) -> Result<()> { |
| 212 | + use std::os::unix::fs::PermissionsExt; |
| 213 | + |
| 214 | + let metadata = fs::metadata(path)?; |
| 215 | + let mut perms = metadata.permissions(); |
| 216 | + perms.set_mode(0o700); |
| 217 | + fs::set_permissions(path, perms)?; |
| 218 | + Ok(()) |
| 219 | +} |
| 220 | + |
| 221 | +#[cfg(not(unix))] |
| 222 | +fn enforce_dir_perms(_path: &Path) -> Result<()> { |
| 223 | + Ok(()) |
| 224 | +} |
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