feat: add 'dbdeployer providers' CLI command (#34)

Closes #30

Author: renecannao

cmd/providers.go

@@ -0,0 +1,26 @@
+package cmd
+
+import (
+	"fmt"
+
+	"github.com/ProxySQL/dbdeployer/providers"
+	"github.com/spf13/cobra"
+)
+
+var providersCmd = &cobra.Command{
+	Use:   "providers",
+	Short: "Shows available deployment providers",
+	Long:  "Lists all registered providers that can be used for sandbox deployment",
+	Run: func(cmd *cobra.Command, args []string) {
+		for _, name := range providers.DefaultRegistry.List() {
+			p, _ := providers.DefaultRegistry.Get(name)
+			ports := p.DefaultPorts()
+			fmt.Printf("%-15s (base port: %d, ports per instance: %d)\n",
+				name, ports.BasePort, ports.PortsPerInstance)
+		}
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(providersCmd)
+}

cmd/single.go

@@ -25,6 +25,7 @@ import (
 	"github.com/ProxySQL/dbdeployer/common"
 	"github.com/ProxySQL/dbdeployer/defaults"
 	"github.com/ProxySQL/dbdeployer/globals"
+	"github.com/ProxySQL/dbdeployer/providers"
 	"github.com/ProxySQL/dbdeployer/sandbox"
 	"github.com/pkg/errors"
 	"github.com/spf13/cobra"
@@ -445,6 +446,15 @@ func singleSandbox(cmd *cobra.Command, args []string) {
 	if err != nil {
 		common.Exitf(1, "error while filling the sandbox definition: %+v", err)
 	}
+	// Validate version with provider
+	// TODO: Phase 2b — determine provider from sd.Flavor instead of hardcoding "mysql"
+	p, provErr := providers.DefaultRegistry.Get("mysql")
+	if provErr != nil {
+		common.Exitf(1, "provider error: %s", provErr)
+	}
+	if provErr = p.ValidateVersion(sd.Version); provErr != nil {
+		common.Exitf(1, "version validation failed: %s", provErr)
+	}
 	// When deploying a single sandbox, we disable concurrency
 	sd.RunConcurrently = false
 	err = sandbox.CreateStandaloneSandbox(sd)