Print provider config in provider get, if any

We used to only print provider config if there was any on `provider
get`. That's not very user-friendly in case the user enables
auto-registration and then runs provider get to see what had changed.

In the usual case where there's no config, we don't print anything. If
there is configuration, we print key-value pairs for each config option.

The key-value pairs work fine for now since we have a low number of
config options. In the future, once our config gets more complicated, we
should just switch to printing the config as YAML, but for now this
looks awkward and the table gets too vertically long for just one
option.

Fixes: #3816

cmd/cli/app/provider/provider_get.go

@@ -18,6 +18,7 @@ package provider
 import (
 	"context"
 	"fmt"
+	"reflect"
 	"strings"
 
 	"github.com/spf13/cobra"
@@ -97,6 +98,10 @@ func GetProviderCommand(ctx context.Context, cmd *cobra.Command, _ []string, con
 		t.AddRow("Version", p.GetVersion())
 		t.AddRow("Implements", strings.Join(impls, ", "))
 		t.AddRow("Auth Flows", strings.Join(afs, ", "))
+		config := configAsKeyValues(p)
+		if config != "" {
+			t.AddRow("Config", config)
+		}
 
 		t.Render()
 		return nil
@@ -106,3 +111,47 @@ func GetProviderCommand(ctx context.Context, cmd *cobra.Command, _ []string, con
 
 	return nil
 }
+
+// mapToKvPairs converts a map to a list of key-value pairs
+// TODO(jakub): This works OK now that we have a low-number of config options
+// if we have more elaborate configs, we might want to just dump the config as YAML, but for the usual
+// case now (1 option..) that would not be very readable
+func mapToKvPairs(m map[string]any, parentKey string, result *[]string, nesting int) {
+	// just in case
+	if nesting > 10 {
+		return
+	}
+
+	for key, value := range m {
+		fullKey := key
+		if parentKey != "" {
+			fullKey = parentKey + "." + key
+		}
+
+		v := reflect.ValueOf(value)
+		switch v.Kind() { // nolint:exhaustive
+		case reflect.Map:
+			nestedMap := value.(map[string]any)
+			mapToKvPairs(nestedMap, fullKey, result, nesting+1)
+		default:
+			// this should work for most types, if not, we'll likely just switch to printing YAML
+			*result = append(*result, fmt.Sprintf("%s=%v", fullKey, value))
+		}
+	}
+}
+
+func configAsKeyValues(p *minderv1.Provider) string {
+	if p == nil {
+		return ""
+	}
+
+	conf := p.GetConfig().AsMap()
+	if conf == nil {
+		return ""
+	}
+
+	var result []string
+	mapToKvPairs(conf, "", &result, 0)
+
+	return strings.Join(result, "\n")
+}