services/federation: discontinue mysql support (#1753)

Discontinue support for MySQL in the Federation service.

#1706 made the decision that we should remove mysql support from Federation due to limited users of that functionality and a lack of maintenance and testing in comparison to the main database solutions the other reference service implementations use, PostgreSQL.

Federation was the last service using MySQL in the repository, which also allows for it to be removed from the CircleCI setup and the client as a dependency.

- Remove mysql from Federation, displaying a meaningful error saying support is discontinued
- Add note to Federation CHANGELOG
- Update READMEs
- Remove from CircleCI config
- Remove packages supporting testing MySQL DBs
- Remove import of MySQL driver

.circleci/config.yml

@@ -132,17 +132,15 @@ commands:
                 sudo apt-get install postgresql-client-9.6
               )
             )
-            (sudo apt-get install mariadb-client-10.1 || sudo apt-get install mariadb-client-10.3)
       - run:
           name: Install dockerize
           command: wget https://github.com/jwilder/dockerize/releases/download/$DOCKERIZE_VERSION/dockerize-linux-amd64-$DOCKERIZE_VERSION.tar.gz && sudo tar -C /usr/local/bin -xzvf dockerize-linux-amd64-$DOCKERIZE_VERSION.tar.gz && rm dockerize-linux-amd64-$DOCKERIZE_VERSION.tar.gz
           environment:
             DOCKERIZE_VERSION: v0.3.0
       - run:
-          name: Wait for mysql, postgres and redis
+          name: Wait for postgres and redis
           command: |
             dockerize -wait tcp://localhost:5432 -timeout 1m
-            dockerize -wait tcp://localhost:3306 -timeout 1m
             dockerize -wait tcp://localhost:6379 -timeout 1m
       - run:
           name: Run package tests
@@ -216,7 +214,6 @@ jobs:
       - image: circleci/postgres:9.6.5-alpine-ram
         environment:
           POSTGRES_USER: circleci
-      - image: circleci/mysql:5.7
       - image: circleci/redis:5.0-alpine
     steps:
       - install_go_deps
@@ -237,7 +234,6 @@ jobs:
       - image: circleci/postgres:9.6.5-alpine-ram
         environment:
           POSTGRES_USER: circleci
-      - image: circleci/mysql:5.7
       - image: circleci/redis:5.0-alpine
     steps:
       - install_go_deps

go.mod

@@ -21,7 +21,6 @@ require (
 	github.com/go-chi/chi v3.1.5+incompatible
 	github.com/go-errors/errors v0.0.0-20150906023321-a41850380601
 	github.com/go-ini/ini v1.23.0 // indirect
-	github.com/go-sql-driver/mysql v1.4.0
 	github.com/gobuffalo/packr v1.12.1 // indirect
 	github.com/goji/httpauth v0.0.0-20160601135302-2da839ab0f4d
 	github.com/gomodule/redigo v2.0.0+incompatible

services/federation/CHANGELOG.md

@@ -11,6 +11,7 @@ bumps.  A breaking change will get clearly notified in this log.
 ### Changed
 
 - BREAKING CHANGE: The `url` database configuration has been renamed to `dsn` to more accurately reflect its content.
+- BREAKING CHANGE: MySQL is no longer supported. To migrate your data to postgresql use any of the tools provided [here](https://wiki.postgresql.org/wiki/Converting_from_other_Databases_to_PostgreSQL#MySQL).
 - Dropped support for Go 1.10, 1.11.
 
 ### Fixed

services/federation/README.md

@@ -13,9 +13,8 @@ By default this server uses a config file named `federation.cfg` in the current
 
 * `port` - server listening port
 * `database`
-  * `type` - database type (sqlite3, mysql, postgres)
+  * `type` - database type (sqlite3, postgres)
   * `dsn` - The DSN (data source name) used to connect to the database connection.  This value should be appropriate for the database type chosen.
-    * for `mysql`: `user:password@(host:port)/dbname` ([more info](https://github.com/go-sql-driver/mysql#dsn-data-source-name))
     * for `postgres`: `postgres://user:password@host/dbname?sslmode=sslmode` ([more info](https://godoc.org/github.com/lib/pq#hdr-Connection_String_Parameters))
 * `queries`
   * `federation` - Implementation dependent query to fetch federation results, should return either 1 or 3 columns. These columns should be labeled `id`,`memo`,`memo_type`. Memo and memo_type are optional - see [Federation](https://www.stellar.org/developers/learn/concepts/federation.html) docs for more detail).  When executed, this query will be provided with two input parameters, the first will be the name portion of a stellar address and the second will be the domain portion of a stellar address.  For example, a request for `scott*stellar.org` would trigger a query with two input parameters, `scott` and `stellar.org` respectively. 
@@ -43,8 +42,8 @@ In the case that every user owns a Stellar account, you don't need `memo`. You c
 port = 8000
 
 [database]
-type = "mysql"
-dsn = "dbuser:dbpassword@/dbname"
+type = "postgres"
+dsn = "postgres://user:password@host/dbname?sslmode=sslmode"
 
 [queries]
 federation = "SELECT account_id as id FROM Users WHERE username = ? AND domain = ?"
@@ -62,8 +61,8 @@ Let's say that your Stellar account ID is: `GD6WU64OEP5C4LRBH6NK3MHYIA2ADN6K6II6
 port = 8000
 
 [database]
-type = "mysql"
-dsn = "dbuser:dbpassword@/dbname"
+type = "postgres"
+dsn = "postgres://user:password@host/dbname?sslmode=sslmode"
 
 [queries]
 federation = "SELECT username as memo, 'text' as memo_type, 'GD6WU64OEP5C4LRBH6NK3MHYIA2ADN6K6II6EXPNVUR3ERBXT4AN4ACD' as id FROM Users WHERE username = ? AND domain = ?"

services/federation/main.go

@@ -19,7 +19,7 @@ import (
 type Config struct {
 	Port     int `valid:"required"`
 	Database struct {
-		Type string `valid:"matches(^mysql|sqlite3|postgres$)"`
+		Type string `valid:"matches(^sqlite3|postgres$)"`
 		DSN  string `valid:"required"`
 	} `valid:"required"`
 	Queries struct {
@@ -89,7 +89,7 @@ func initDriver(cfg Config) (federation.Driver, error) {
 
 	switch cfg.Database.Type {
 	case "mysql":
-		dialect = "mysql"
+		return nil, errors.Errorf("Invalid db type: %s, mysql support is discontinued", cfg.Database.Type)
 	case "postgres":
 		dialect = "postgres"
 	case "sqlite3":

services/federation/main_test.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/stellar/go/support/db/dbtest"
+	"github.com/stellar/go/support/errors"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestInitDriver_dialect(t *testing.T) {
+	c := Config{}
+
+	testCases := []struct {
+		dbType  string
+		dbDSN   string
+		wantErr error
+	}{
+		{dbType: "", wantErr: errors.New("Invalid db type: ")},
+		{dbType: "postgres", dbDSN: dbtest.Postgres(t).DSN, wantErr: nil},
+		{dbType: "mysql", wantErr: errors.New("Invalid db type: mysql, mysql support is discontinued")},
+		{dbType: "bogus", wantErr: errors.New("Invalid db type: bogus")},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.dbType, func(t *testing.T) {
+			c.Database.Type = tc.dbType
+			c.Database.DSN = tc.dbDSN
+			_, err := initDriver(c)
+			if tc.wantErr == nil {
+				require.Nil(t, err)
+			} else {
+				require.NotNil(t, err)
+				assert.Equal(t, tc.wantErr.Error(), err.Error())
+			}
+		})
+	}
+}

support/db/main.go

@@ -19,8 +19,6 @@ import (
 	"github.com/jmoiron/sqlx"
 	"github.com/stellar/go/support/errors"
 
-	// Enable mysql
-	_ "github.com/go-sql-driver/mysql"
 	// Enable postgres
 	_ "github.com/lib/pq"
 )