Refactor drivers into separate packages (#179)

`dbmate` package was starting to get a bit polluted. This PR migrates each driver into a separate package, with clean separation between each.

In addition:

* Drivers are now initialized with a URL, avoiding the need to pass `*url.URL` to every method
* Sqlite supports a cleaner syntax for relative paths
* Driver tests now load their test URL from environment variables

Public API of `dbmate` package has not changed (no changes to `main` package).

.golangci.yml

@@ -26,3 +26,7 @@ linters-settings:
     local-prefixes: github.com/amacneil/dbmate
   misspell:
     locale: US
+
+issues:
+  include:
+    - EXC0002

Makefile

@@ -3,14 +3,14 @@ LDFLAGS := -ldflags '-s'
 # statically link binaries (to support alpine + scratch containers)
 STATICLDFLAGS := -ldflags '-s -extldflags "-static"'
 # avoid building code that is incompatible with static linking
-TAGS := -tags netgo,osusergo,sqlite_omit_load_extension
+TAGS := -tags netgo,osusergo,sqlite_omit_load_extension,sqlite_json
 
 .PHONY: all
-all: build lint test
+all: build test lint
 
 .PHONY: test
 test:
-	go test -v $(TAGS) $(STATICLDFLAGS) ./...
+	go test -p 1 $(TAGS) $(STATICLDFLAGS) ./...
 
 .PHONY: fix
 fix:
@@ -22,9 +22,9 @@ lint:
 
 .PHONY: wait
 wait:
-	dist/dbmate-linux-amd64 -e MYSQL_URL wait
-	dist/dbmate-linux-amd64 -e POSTGRESQL_URL wait
-	dist/dbmate-linux-amd64 -e CLICKHOUSE_URL wait
+	dist/dbmate-linux-amd64 -e CLICKHOUSE_TEST_URL wait
+	dist/dbmate-linux-amd64 -e MYSQL_TEST_URL wait
+	dist/dbmate-linux-amd64 -e POSTGRES_TEST_URL wait
 
 .PHONY: clean
 clean:

README.md

@@ -152,16 +152,16 @@ DATABASE_URL="postgres://username:[email protected]:5432/database_name?search_p
 
 **SQLite**
 
-SQLite databases are stored on the filesystem, so you do not need to specify a host. By default, files are relative to the current directory. For example, the following will create a database at `./db/database_name.sqlite3`:
+SQLite databases are stored on the filesystem, so you do not need to specify a host. By default, files are relative to the current directory. For example, the following will create a database at `./db/database.sqlite3`:
 
 ```sh
-DATABASE_URL="sqlite:///db/database_name.sqlite3"
+DATABASE_URL="sqlite:db/database.sqlite3"
 ```
 
-To specify an absolute path, add an additional forward slash to the path. The following will create a database at `/tmp/database_name.sqlite3`:
+To specify an absolute path, add a forward slash to the path. The following will create a database at `/tmp/database.sqlite3`:
 
 ```sh
-DATABASE_URL="sqlite:////tmp/database_name.sqlite3"
+DATABASE_URL="sqlite:/tmp/database.sqlite3"
 ```
 
 **ClickHouse**

docker-compose.yml

@@ -11,9 +11,10 @@ services:
       - postgres
       - clickhouse
     environment:
-      MYSQL_URL: mysql://root:root@mysql/dbmate
-      POSTGRESQL_URL: postgres://postgres:postgres@postgres/dbmate?sslmode=disable
-      CLICKHOUSE_URL: clickhouse://clickhouse:9000?database=dbmate
+      CLICKHOUSE_TEST_URL: clickhouse://clickhouse:9000?database=dbmate_test
+      MYSQL_TEST_URL: mysql://root:root@mysql/dbmate_test
+      POSTGRES_TEST_URL: postgres://postgres:postgres@postgres/dbmate_test?sslmode=disable
+      SQLITE_TEST_URL: sqlite3:/tmp/dbmate_test.sqlite3
 
   dbmate:
     build:

go.sum

@@ -1,3 +1,4 @@
+github.com/BurntSushi/toml v0.3.1 h1:WXkYYl6Yr3qBf1K79EBnL4mak0OimBfB0XUf9Vl28OQ=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
 github.com/ClickHouse/clickhouse-go v1.4.3 h1:iAFMa2UrQdR5bHJ2/yaSLffZkxpcOYQMCUuKeNXGdqc=
 github.com/ClickHouse/clickhouse-go v1.4.3/go.mod h1:EaI/sW7Azgz9UATzd5ZdZHRUhHgv5+JMS9NSr2smCJI=

main.go

@@ -11,6 +11,10 @@ import (
 	"github.com/urfave/cli/v2"
 
 	"github.com/amacneil/dbmate/pkg/dbmate"
+	_ "github.com/amacneil/dbmate/pkg/driver/clickhouse"
+	_ "github.com/amacneil/dbmate/pkg/driver/mysql"
+	_ "github.com/amacneil/dbmate/pkg/driver/postgres"
+	_ "github.com/amacneil/dbmate/pkg/driver/sqlite"
 )
 
 func main() {