From d97a10d1b3275dc88a627729f1a519cfb56fc95f Mon Sep 17 00:00:00 2001
From: Varsha Varadarajan <vvaradarajan@digitalocean.com>
Date: Fri, 28 Jun 2019 09:42:21 -0400
Subject: [PATCH] List command: Provide option to whitelist and blacklist
 groups for listing

---
 checks/commands.go      | 59 +++++++++++++++++++++++++++++++++++++++++
 checks/registry.go      | 15 +++++++++++
 cmd/clusterlint/main.go | 26 +++++++-----------
 3 files changed, 83 insertions(+), 17 deletions(-)
 create mode 100644 checks/commands.go

diff --git a/checks/commands.go b/checks/commands.go
new file mode 100644
index 0000000..4cf8bf1
--- /dev/null
+++ b/checks/commands.go
@@ -0,0 +1,59 @@
+package checks
+
+import (
+	"fmt"
+
+	"github.com/urfave/cli"
+)
+
+// ListChecks lists the names and desc of all checks in the group if found
+// lists all checks in the registry if group is not specified
+func ListChecks(c *cli.Context) error {
+	allChecks, err := filter(c)
+	if err != nil {
+		return err
+	}
+	for _, check := range allChecks {
+		fmt.Printf("%s : %s\n", check.Name(), check.Description())
+	}
+
+	return nil
+}
+
+func filter(c *cli.Context) ([]Check, error) {
+	whitelist := c.StringSlice("g")
+	blacklist := c.StringSlice("G")
+	if len(whitelist) > 0 && len(blacklist) > 0 {
+		return nil, fmt.Errorf("cannot specify both g and G flags")
+	}
+
+	if len(whitelist) > 0 {
+		return GetGroups(whitelist), nil
+	} else if len(blacklist) > 0 {
+		return getChecksNotInGroups(blacklist), nil
+	} else {
+		return List(), nil
+	}
+}
+
+// getChecksInGroups retrieves all checks within specified set of groups
+// returns all checks in the registry if `groups` is unspecified
+func getChecksNotInGroups(groups []string) []Check {
+	allGroups := ListGroups()
+	var ret []Check
+	for _, group := range allGroups {
+		if !contains(groups, group) {
+			ret = append(ret, GetGroup(group)...)
+		}
+	}
+	return ret
+}
+
+func contains(groups []string, group string) bool {
+	for _, g := range groups {
+		if g == group {
+			return true
+		}
+	}
+	return false
+}
diff --git a/checks/registry.go b/checks/registry.go
index 93c7069..bbbe732 100644
--- a/checks/registry.go
+++ b/checks/registry.go
@@ -85,6 +85,21 @@ func GetGroup(name string) []Check {
 	return ret
 }
 
+// GetGroups returns checks that belong to any of the specified group.
+func GetGroups(groups []string) []Check {
+	registry.mu.RLock()
+	defer registry.mu.RUnlock()
+	var ret []Check
+	for _, group := range groups {
+		if checks, ok := registry.groups[group]; ok {
+			ret = append(ret, checks...)
+		}
+		// else do we log an error?
+	}
+
+	return ret
+}
+
 // Get retrieves the specified check from the registry,
 // throws an error if not found
 func Get(name string) (Check, error) {
diff --git a/cmd/clusterlint/main.go b/cmd/clusterlint/main.go
index a8a0a3c..9578955 100644
--- a/cmd/clusterlint/main.go
+++ b/cmd/clusterlint/main.go
@@ -36,12 +36,16 @@ func main() {
 			Name:  "list",
 			Usage: "list all checks in the registry",
 			Flags: []cli.Flag{
-				cli.StringFlag{
-					Name:  "group, g",
-					Usage: "list all checks in group `GROUP`",
+				cli.StringSliceFlag{
+					Name:  "g",
+					Usage: "list all checks in groups `GROUP1, GROUP2`",
+				},
+				cli.StringSliceFlag{
+					Name:  "G",
+					Usage: "list all checks not in groups `GROUP1, GROUP2`",
 				},
 			},
-			Action: listChecks,
+			Action: checks.ListChecks,
 		},
 		{
 			Name:  "run",
@@ -74,18 +78,6 @@ func main() {
 	}
 }
 
-// listChecks lists the names and desc of all checks in the group if found
-// lists all checks in the registry if group is not specified
-func listChecks(c *cli.Context) error {
-	group := c.String("group")
-	allChecks := getChecks(group)
-	for _, check := range allChecks {
-		fmt.Printf("%s : %s\n", check.Name(), check.Description())
-	}
-
-	return nil
-}
-
 func runChecks(c *cli.Context) error {
 	group := c.String("group")
 	name := c.String("name")
@@ -185,7 +177,7 @@ func filter(level checks.Severity, diagnostics []checks.Diagnostic) []checks.Dia
 }
 
 // getChecks retrieves all checks within given group
-// returns all checks in the registry if group in unspecified
+// returns all checks in the registry if group is unspecified
 func getChecks(group string) []checks.Check {
 	if group == "" {
 		return checks.List()