max / goingson

2.7 KB · 67 lines History Blame Raw

1	//! Embeds `migrations/sqlite/*.sql` into the binary.
2	//!
3	//! This replaces what `sqlx::migrate!` did as a proc macro. The generated table
4	//! is `(version, description, sql)`; checksums are computed at runtime rather
5	//! than baked in, so the manifest test and the runner agree by construction.
6	//!
7	//! Filename parsing matches sqlx's exactly -- `<version>_<description>.sql`,
8	//! with `_` becoming a space in the description -- because the `_sqlx_migrations`
9	//! ledger in every existing install was written by sqlx and keeps being read and
10	//! appended to by the runner in `migrate.rs`.
11
12	use std::fmt::Write as _;
13	use std::path::{Path, PathBuf};
14
15	fn main() {
16	let dir = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("../../migrations/sqlite");
17	let dir = dir.canonicalize().unwrap_or(dir);
18
19	// Re-run when a migration is added, removed or edited.
20	println!("cargo:rerun-if-changed={}", dir.display());
21
22	let mut entries: Vec<(i64, String, PathBuf)> = Vec::new();
23	for entry in std::fs::read_dir(&dir).expect("migrations/sqlite is unreadable") {
24	let path = entry.expect("unreadable dir entry").path();
25	let Some(name) = path.file_name().and_then(\|n\| n.to_str()) else {
26	continue;
27	};
28	// sqlx skips anything not matching <version>_<rest>.sql. CHECKSUMS lands here.
29	let Some((version, rest)) = name.split_once('_') else {
30	continue;
31	};
32	if !Path::new(rest)
33	.extension()
34	.is_some_and(\|ext\| ext.eq_ignore_ascii_case("sql"))
35	{
36	continue;
37	}
38	let Ok(version) = version.parse::<i64>() else {
39	panic!("migration {name}: expected an integer version prefix");
40	};
41	let description = rest.trim_end_matches(".sql").replace('_', " ");
42	println!("cargo:rerun-if-changed={}", path.display());
43	entries.push((version, description, path));
44	}
45
46	entries.sort_by_key(\|(version, _, _)\| *version);
47	if let Some(dup) = entries.windows(2).find(\|w\| w[0].0 == w[1].0) {
48	panic!("duplicate migration version {}", dup[0].0);
49	}
50
51	let mut out = String::from(
52	"// @generated by build.rs from migrations/sqlite. Do not edit.\n\
53	pub(crate) static MIGRATIONS: &[(i64, &str, &str)] = &[\n",
54	);
55	for (version, description, path) in &entries {
56	let _ = writeln!(
57	out,
58	" ({version}, {description:?}, include_str!({:?})),",
59	path.display().to_string()
60	);
61	}
62	out.push_str("];\n");
63
64	let dest = Path::new(&std::env::var("OUT_DIR").expect("OUT_DIR unset")).join("migrations.rs");
65	std::fs::write(&dest, out).expect("failed to write generated migrations");
66	}
67