Merge pull request authzed#1738 from josephschorr/datastore-readme

Add missing datastore READMEs

internal/datastore/mysql/README.md

@@ -0,0 +1,9 @@
+# MySQL Datastore
+
+**Minimum required version** can be found here defined as `MinimumSupportedMySQLVersion` in [version.go](version/version.go)
+
+This datastore implementation allows you to use a MySQL database as the backing durable storage for SpiceDB.
+
+## Usage Caveats
+
+The MySQL datastore only supports a single primary node, and does not support read replicas. It is therefore only recommended for installations that can scale the MySQL instance vertically and cannot be used efficiently in a mulit-region installation.

internal/datastore/mysql/version/version.go

@@ -0,0 +1,6 @@
+package version
+
+// MinimumSupportedMySQLVersion is the minimum version of MySQL supported for this driver.
+//
+// NOTE: must match a tag on DockerHub for the `mysql` image.
+const MinimumSupportedMySQLVersion = "8.0"

internal/datastore/spanner/README.md

@@ -0,0 +1,7 @@
+# Spanner Datastore
+
+This datastore implementation allows you to use a [Google Cloud Spanner](https://cloud.google.com/spanner) database as the backing durable storage for SpiceDB.
+
+## Usage Benefits
+
+The Spanner datastore, like the CockroachDB datastore, can be used in highly scalable and multi-region installations.

internal/testserver/datastore/mysql.go

@@ -14,6 +14,7 @@ import (
 	"github.com/stretchr/testify/require"
 
 	"github.com/authzed/spicedb/internal/datastore/mysql/migrations"
+	"github.com/authzed/spicedb/internal/datastore/mysql/version"
 	"github.com/authzed/spicedb/pkg/datastore"
 	"github.com/authzed/spicedb/pkg/migrate"
 	"github.com/authzed/spicedb/pkg/secrets"
@@ -52,7 +53,7 @@ func RunMySQLForTestingWithOptions(t testing.TB, options MySQLTesterOptions, bri
 	pool, err := dockertest.NewPool("")
 	require.NoError(t, err)
 
-	containerImageTag := "8"
+	containerImageTag := version.MinimumSupportedMySQLVersion
 
 	name := fmt.Sprintf("mysql-%s", uuid.New().String())
 	resource, err := pool.RunWithOptions(&dockertest.RunOptions{