build/sqlc: implement simple sqlc/bindata rules
This is a first pass at implementing rules to generate sqlc stubs from
.sql files and embed relevant migration files into bindata.
This is not yet used. The Go API is subject to change - especially the
way migrations are laid out in the generated package will probably
change.
Change-Id: I0873031603957a176ad4664c3b10768b791e0dd5
Reviewed-on: https://review.monogon.dev/c/monogon/+/884
Tested-by: Jenkins CI
Reviewed-by: Leopold Schabel <leo@monogon.tech>
diff --git a/build/sqlc/README.md b/build/sqlc/README.md
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+Bazel rules for sqlc
+===
+
+This is a set of rules which uses [sqlc](https://github.com/kyleconroy/sqlc) to generate Go code (types and functions) based on a SQL schema/migrations and a list of queries to be turned into functions.
+
+It also embeds the migrations using [bindata](https://github.com/kevinburke/go-bindata).
+
+Usage
+---
+
+In an empty directory (eg. monogon/foo/bar/model), create:
+
+ - Migration files, eg. `1662395623_foo.up.sql` and `1662395623_foo.down.sql` containing CREATE TABLE and DROP TABLE statements respectively.
+ - A query file, containing SQL queries annotated with function names and return values (see [official docs](https://docs.sqlc.dev/en/stable/tutorials/getting-started-postgresql.html) for a sample `query.sql` file).
+ - A `BUILD.bazel` file containing:
+
+```
+load("@io_bazel_rules_go//go:def.bzl", "go_library")
+load("//build/sqlc:sqlc.bzl", "sqlc_go_library")
+
+sqlc_go_library(
+ name = "sqlc_model",
+ importpath = "source.monogon.dev/foo/bar/model",
+ migrations = [
+ "1662395623_foo.up.sql",
+ "1662395623_foo.down.sql",
+ # More migrations can be created by provising larger timestamp values.
+ ],
+ queries = [
+ "queries.sql",
+ ],
+ dialect = "cockroachdb",
+)
+
+go_library(
+ name = "model",
+ importpath = "source.monogon.dev/foo/bar/model",
+ embed = [":sqlc_model"],
+ deps = [
+ # Might need this for CockroachDB UUID types.
+ "@com_github_google_uuid//:uuid",
+ ],
+)
+```
+
+The built `go_library ` will contain sqlc functions corresponding to queries defined in `queries.sql` and structures corresponding to database tables (and query parameters/results).
+
+To list the generated files for inspection/debugging, `bazel aquery //foo/bar:sqlc_model` and find files named `db.go`, `model.go` and `queries.sql.go` (or similar, depending on how your query file(s) are named).
+
+TODO(q3k): document migrations (and probably move them to a subpackage).
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