Fix GitHub teams for large orgs

Some large organisations have more than 100 teams. The current
implementation only checks the first 100 teams returned by the
API. This checks all teams the user is a member of.

Added support for GitHub's new nested team feature which means
inheritence works as designed. Again useful for large orgs.

Updated the limit from 200 to the documented limit of 100:
https://developer.github.com/v3/#pagination

Author: skwashd

providers/github.go

@@ -8,6 +8,7 @@ import (
 	"net/http"
 	"net/url"
 	"path"
+	"regexp"
 	"strconv"
 	"strings"
 )
@@ -69,7 +70,7 @@ func (p *GitHubProvider) hasOrg(accessToken string) (bool, error) {
 	pn := 1
 	for {
 		params := url.Values{
-			"limit": {"200"},
+			"limit": {"100"},
 			"page":  {strconv.Itoa(pn)},
 		}
 
@@ -134,7 +135,7 @@ func (p *GitHubProvider) hasOrgAndTeam(accessToken string) (bool, error) {
 	}
 
 	params := url.Values{
-		"limit": {"200"},
+		"limit": {"100"},
 	}
 
 	endpoint := &url.URL{
@@ -143,45 +144,58 @@ func (p *GitHubProvider) hasOrgAndTeam(accessToken string) (bool, error) {
 		Path:     path.Join(p.ValidateURL.Path, "/user/teams"),
 		RawQuery: params.Encode(),
 	}
-	req, _ := http.NewRequest("GET", endpoint.String(), nil)
-	req.Header.Set("Accept", "application/vnd.github.v3+json")
-	req.Header.Set("Authorization", fmt.Sprintf("token %s", accessToken))
-	resp, err := http.DefaultClient.Do(req)
-	if err != nil {
-		return false, err
-	}
-
-	body, err := ioutil.ReadAll(resp.Body)
-	resp.Body.Close()
-	if err != nil {
-		return false, err
-	}
-	if resp.StatusCode != 200 {
-		return false, fmt.Errorf(
-			"got %d from %q %s", resp.StatusCode, endpoint.String(), body)
-	}
-
-	if err := json.Unmarshal(body, &teams); err != nil {
-		return false, fmt.Errorf("%s unmarshaling %s", err, body)
-	}
+	team_url := endpoint.String()
 
+	pattern := regexp.MustCompile(`<([^>]+)>; rel="next"`)
 	var hasOrg bool
 	presentOrgs := make(map[string]bool)
 	var presentTeams []string
-	for _, team := range teams {
-		presentOrgs[team.Org.Login] = true
-		if p.Org == team.Org.Login {
-			hasOrg = true
-			ts := strings.Split(p.Team, ",")
-			for _, t := range ts {
-				if t == team.Slug {
-					log.Printf("Found Github Organization:%q Team:%q (Name:%q)", team.Org.Login, team.Slug, team.Name)
-					return true, nil
+	for {
+		req, _ := http.NewRequest("GET", team_url, nil)
+		req.Header.Set("Accept", "application/vnd.github.hellcat-preview+json")
+		req.Header.Set("Authorization", fmt.Sprintf("token %s", accessToken))
+		resp, err := http.DefaultClient.Do(req)
+		if err != nil {
+			return false, err
+		}
+
+		body, err := ioutil.ReadAll(resp.Body)
+		resp.Body.Close()
+		if err != nil {
+			return false, err
+		}
+		if resp.StatusCode != 200 {
+			return false, fmt.Errorf(
+				"got %d from %q %s", resp.StatusCode, endpoint.String(), body)
+		}
+
+		if err := json.Unmarshal(body, &teams); err != nil {
+			return false, fmt.Errorf("%s unmarshaling %s", err, body)
+		}
+
+		for _, team := range teams {
+			presentOrgs[team.Org.Login] = true
+			if p.Org == team.Org.Login {
+				hasOrg = true
+				ts := strings.Split(p.Team, ",")
+				for _, t := range ts {
+					if t == team.Slug {
+						log.Printf("Found Github Organization:%q Team:%q (Name:%q)",
+							team.Org.Login, team.Slug, team.Name)
+						return true, nil
+					}
 				}
+				presentTeams = append(presentTeams, team.Slug)
 			}
-			presentTeams = append(presentTeams, team.Slug)
 		}
+
+		matches := pattern.FindStringSubmatch(resp.Header["Link"][0])
+		if len(matches) == 0 {
+			break
+		}
+		team_url = matches[1]
 	}
+
 	if hasOrg {
 		log.Printf("Missing Team:%q from Org:%q in teams: %v", p.Team, p.Org, presentTeams)
 	} else {

providers/github_test.go

@@ -31,7 +31,7 @@ func testGitHubBackend(payload []string) *httptest.Server {
 	pathToQueryMap := map[string][]string{
 		"/user":        []string{""},
 		"/user/emails": []string{""},
-		"/user/orgs":   []string{"limit=200&page=1", "limit=200&page=2", "limit=200&page=3"},
+		"/user/orgs":   []string{"limit=100&page=1", "limit=100&page=2", "limit=100&page=3"},
 	}
 
 	return httptest.NewServer(http.HandlerFunc(