connectors: refactor filter code into a helper package

I hope I didn't miss any :D
Signed-off-by: Stephan Renatus <srenatus@chef.io>

connector/bitbucketcloud/bitbucketcloud.go

@@ -6,7 +6,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"github.com/dexidp/dex/pkg/log"
 	"io/ioutil"
 	"net/http"
 	"sync"
@@ -16,6 +15,8 @@ import (
 	"golang.org/x/oauth2/bitbucket"
 
 	"github.com/dexidp/dex/connector"
+	"github.com/dexidp/dex/pkg/groups"
+	"github.com/dexidp/dex/pkg/log"
 )
 
 const (
@@ -350,7 +351,7 @@ func (b *bitbucketConnector) getGroups(ctx context.Context, client *http.Client,
 	}
 
 	if len(b.teams) > 0 {
-		filteredTeams := filterTeams(bitbucketTeams, b.teams)
+		filteredTeams := groups.Filter(bitbucketTeams, b.teams)
 		if len(filteredTeams) == 0 {
 			return nil, fmt.Errorf("bitbucket: user %q is not in any of the required teams", userLogin)
 		}
@@ -362,21 +363,6 @@ func (b *bitbucketConnector) getGroups(ctx context.Context, client *http.Client,
 	return nil, nil
 }
 
-// Filter the users' team memberships by 'teams' from config.
-func filterTeams(userTeams, configTeams []string) []string {
-	teams := []string{}
-	teamFilter := make(map[string]struct{})
-	for _, team := range configTeams {
-		teamFilter[team] = struct{}{}
-	}
-	for _, team := range userTeams {
-		if _, ok := teamFilter[team]; ok {
-			teams = append(teams, team)
-		}
-	}
-	return teams
-}
-
 type team struct {
 	Name string `json:"username"` // The "username" from Bitbucket Cloud is actually the team name here
 }

connector/github/github.go

@@ -20,6 +20,7 @@ import (
 	"golang.org/x/oauth2/github"
 
 	"github.com/dexidp/dex/connector"
+	groups_pkg "github.com/dexidp/dex/pkg/groups"
 	"github.com/dexidp/dex/pkg/log"
 )
 
@@ -375,7 +376,7 @@ func (c *githubConnector) groupsForOrgs(ctx context.Context, client *http.Client
 		// 'teams' list in config.
 		if len(org.Teams) == 0 {
 			inOrgNoTeams = true
-		} else if teams = filterTeams(teams, org.Teams); len(teams) == 0 {
+		} else if teams = groups_pkg.Filter(teams, org.Teams); len(teams) == 0 {
 			c.logger.Infof("github: user %q in org %q but no teams", userName, org.Name)
 		}
 
@@ -466,22 +467,6 @@ func (c *githubConnector) userOrgTeams(ctx context.Context, client *http.Client)
 	return groups, nil
 }
 
-// Filter the users' team memberships by 'teams' from config.
-func filterTeams(userTeams, configTeams []string) (teams []string) {
-	teamFilter := make(map[string]struct{})
-	for _, team := range configTeams {
-		if _, ok := teamFilter[team]; !ok {
-			teamFilter[team] = struct{}{}
-		}
-	}
-	for _, team := range userTeams {
-		if _, ok := teamFilter[team]; ok {
-			teams = append(teams, team)
-		}
-	}
-	return
-}
-
 // get creates a "GET `apiURL`" request with context, sends the request using
 // the client, and decodes the resulting response body into v. A pagination URL
 // is returned if one exists. Any errors encountered when building requests,

connector/gitlab/gitlab.go

@@ -13,6 +13,7 @@ import (
 	"golang.org/x/oauth2"
 
 	"github.com/dexidp/dex/connector"
+	"github.com/dexidp/dex/pkg/groups"
 	"github.com/dexidp/dex/pkg/log"
 )
 
@@ -273,7 +274,7 @@ func (c *gitlabConnector) getGroups(ctx context.Context, client *http.Client, gr
 	}
 
 	if len(c.groups) > 0 {
-		filteredGroups := filterGroups(gitlabGroups, c.groups)
+		filteredGroups := groups.Filter(gitlabGroups, c.groups)
 		if len(filteredGroups) == 0 {
 			return nil, fmt.Errorf("gitlab: user %q is not in any of the required groups", userLogin)
 		}
@@ -284,18 +285,3 @@ func (c *gitlabConnector) getGroups(ctx context.Context, client *http.Client, gr
 
 	return nil, nil
 }
-
-// Filter the users' group memberships by 'groups' from config.
-func filterGroups(userGroups, configGroups []string) []string {
-	groups := []string{}
-	groupFilter := make(map[string]struct{})
-	for _, group := range configGroups {
-		groupFilter[group] = struct{}{}
-	}
-	for _, group := range userGroups {
-		if _, ok := groupFilter[group]; ok {
-			groups = append(groups, group)
-		}
-	}
-	return groups
-}

connector/microsoft/microsoft.go

@@ -15,6 +15,7 @@ import (
 	"golang.org/x/oauth2"
 
 	"github.com/dexidp/dex/connector"
+	groups_pkg "github.com/dexidp/dex/pkg/groups"
 	"github.com/dexidp/dex/pkg/log"
 )
 
@@ -311,22 +312,9 @@ func (c *microsoftConnector) getGroups(ctx context.Context, client *http.Client,
 	}
 
 	// ensure that the user is in at least one required group
-	isInGroups := false
-	if len(c.groups) > 0 {
-		gs := make(map[string]struct{})
-		for _, g := range c.groups {
-			gs[g] = struct{}{}
-		}
-
-		for _, g := range groups {
-			if _, ok := gs[g]; ok {
-				isInGroups = true
-				break
-			}
-		}
-	}
-	if len(c.groups) > 0 && !isInGroups {
-		return nil, fmt.Errorf("microsoft: user %v not in required groups", userID)
+	filteredGroups := groups_pkg.Filter(groups, c.groups)
+	if len(c.groups) > 0 && len(filteredGroups) == 0 {
+		return nil, fmt.Errorf("microsoft: user %v not in any of the required groups", userID)
 	}
 
 	return

pkg/groups/groups.go

+// Package groups contains helper functions related to groups
+package groups
+
+// Filter filters out any groups of given that are not in required. Thus it may
+// happen that the resulting slice is empty.
+func Filter(given, required []string) []string {
+	groups := []string{}
+	groupFilter := make(map[string]struct{})
+	for _, group := range required {
+		groupFilter[group] = struct{}{}
+	}
+	for _, group := range given {
+		if _, ok := groupFilter[group]; ok {
+			groups = append(groups, group)
+		}
+	}
+	return groups
+}

pkg/groups/groups_test.go

+package groups_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/dexidp/dex/pkg/groups"
+)
+
+func TestFilter(t *testing.T) {
+	cases := map[string]struct {
+		given, required, expected []string
+	}{
+		"nothing given":                 {given: []string{}, required: []string{"ops"}, expected: []string{}},
+		"exactly one match":             {given: []string{"foo"}, required: []string{"foo"}, expected: []string{"foo"}},
+		"no group of the required ones": {given: []string{"foo", "bar"}, required: []string{"baz"}, expected: []string{}},
+		"subset matching":               {given: []string{"foo", "bar", "baz"}, required: []string{"bar", "baz"}, expected: []string{"bar", "baz"}},
+	}
+	for name, tc := range cases {
+		t.Run(name, func(t *testing.T) {
+			actual := groups.Filter(tc.given, tc.required)
+			assert.ElementsMatch(t, tc.expected, actual)
+		})
+	}
+}