The SQLite command line has facilities to ingest things like csv, and
other formats. But here we are, in 2025, and I asked Claude if Turso's
CLI should, in the same vein, have a native MCP server.
Claude told me: "You're absolutely right!" "That's a great insight!"
"That's a fantastic idea!" and then proceeded to help me with the
boilerplate for this beautiful server.
Rust has a crate, mcp_server, that implements an mcp_server trait.
However, that depends on Tokio, and I think that would bloat our binary
too much.
I have also considered implementing an MCP server that operates on a
directory and allows to list many SQLite files, but figured that would
be a good job for a more advanced and specialized server, not for the
one that comes by default with the CLI. Let's go for simple.
Makes it easier to test the feature:
```
$ cargo run -- --experimental-indexes
Limbo v0.0.22
Enter ".help" for usage hints.
Connected to a transient in-memory database.
Use ".open FILENAME" to reopen on a persistent database
limbo> CREATE TABLE t(x);
limbo> CREATE INDEX t_idx ON t(x);
limbo> DROP INDEX t_idx;
```
The `cargo-dist` tool attempts to find it but because we never build it,
packaging fails. Remove the extra binary. Probably better to work
towards making experimental indexes a runtime flag instead.
Currently indexes are the bulk of the problem with `UPDATE` and
`DELETE`, while we work on fixing those it makes sense to disable
indexing since they are not stable. We want to try to make everything
else stable before we continue with indexing.
I don't know when and why we dropped log::* in favor of tracing but when it was done, it made relevant logs not appear any more while debugging so... I added test_log::test which helps by automatically adding info logs from trace package.
This makes io_uring the default in CLI, but makes it non-default in
core. Before, if one built CLI without io_uring, core still built with
it as it was a default feature. To accommodate for the change, all
bindings have been updated to select the feature, except for WASM which
has a separate fs implementation.
This also adds some #[cfg] and #[allow] to silence unused-* warnings,
which I discovered when testing with different features disabled.
Closes#942
I noticed that the parse errors were a bit hard to read - only the nearest token and the line/col offsets were printed.
I made a first attempt at improving the errors using [miette](https://github.com/zkat/miette).
- Added derive for `miette::Diagnostic` to both the parser's error type and LimboError.
- Added miette dependency to both sqlite3_parser and core. The `fancy` feature is only enabled for CLI.
Some future improvements that can be made further:
- Add spans to AST nodes so that errors can better point to the correct token. See upstream issue: https://github.com/gwenn/lemon-rs/issues/33
- Construct more errors with offset information. I noticed that most parser errors are constructed with `None` as the offset.
Comparisons.
Before:
```
❯ cargo run --package limbo --bin limbo database.db --output-mode pretty
...
limbo> selet * from a;
[2025-01-05T11:22:55Z ERROR sqlite3Parser] near "Token([115, 101, 108, 101, 116])": syntax error
Parse error: near "selet": syntax error at (1, 6)
```
After:
```
❯ cargo run --package limbo --bin limbo database.db --output-mode pretty
...
limbo> selet * from a;
[2025-01-05T12:25:52Z ERROR sqlite3Parser] near "Token([115, 101, 108, 101, 116])": syntax error
× near "selet": syntax error at (1, 6)
╭────
1 │ selet * from a
· ▲
· ╰── syntax error
╰────
```
