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| 1 | +package main |
| 2 | + |
| 3 | +import ( |
| 4 | + "bufio" |
| 5 | + "encoding/json" |
| 6 | + "flag" |
| 7 | + "fmt" |
| 8 | + yaml "gopkg.in/yaml.v2" |
| 9 | + "net/http" |
| 10 | + "net/url" |
| 11 | + "os" |
| 12 | + "os/exec" |
| 13 | + "strings" |
| 14 | +) |
| 15 | + |
| 16 | +const Version = "0.0.1" |
| 17 | + |
| 18 | +var version = flag.Bool("version", false, "print version and exit") |
| 19 | + |
| 20 | +var openBrowser = flag.Bool("open", false, "Open the oauth approval URL in the browser") |
| 21 | + |
| 22 | +var clientIDFlag = flag.String("client-id", "", "The ClientID for the application") |
| 23 | +var clientSecretFlag = flag.String("client-secret", "", "The ClientSecret for the application") |
| 24 | +var appFile = flag.String("config", "", "Path to a json file containing your application's ClientID and ClientSecret.") |
| 25 | + |
| 26 | +const oauthUrl = "https://accounts.google.com/o/oauth2/auth?redirect_uri=urn:ietf:wg:oauth:2.0:oob&response_type=code&client_id=%s&scope=openid+email+profile&approval_prompt=force&access_type=offline" |
| 27 | + |
| 28 | +type ConfigFile struct { |
| 29 | + Installed *GoogleConfig `json:"installed"` |
| 30 | +} |
| 31 | + |
| 32 | +type GoogleConfig struct { |
| 33 | + ClientID string `json:"client_id"` |
| 34 | + ClientSecret string `json:"client_secret"` |
| 35 | +} |
| 36 | + |
| 37 | +type TokenResponse struct { |
| 38 | + AccessToken string `json:"access_token"` |
| 39 | + RefreshToken string `json:"refresh_token"` |
| 40 | + IdToken string `json:"id_token"` |
| 41 | +} |
| 42 | + |
| 43 | +func readConfig(path string) (*GoogleConfig, error) { |
| 44 | + f, err := os.Open(path) |
| 45 | + defer f.Close() |
| 46 | + if err != nil { |
| 47 | + return nil, err |
| 48 | + } |
| 49 | + cf := &ConfigFile{} |
| 50 | + err = json.NewDecoder(f).Decode(cf) |
| 51 | + if err != nil { |
| 52 | + return nil, err |
| 53 | + } |
| 54 | + return cf.Installed, nil |
| 55 | +} |
| 56 | + |
| 57 | +// Get the id_token and refresh_token from google |
| 58 | +func getTokens(clientID, clientSecret, code string) (*TokenResponse, error) { |
| 59 | + val := url.Values{} |
| 60 | + val.Add("grant_type", "authorization_code") |
| 61 | + val.Add("redirect_uri", "urn:ietf:wg:oauth:2.0:oob") |
| 62 | + val.Add("client_id", clientID) |
| 63 | + val.Add("client_secret", clientSecret) |
| 64 | + val.Add("code", code) |
| 65 | + |
| 66 | + resp, err := http.PostForm("https://www.googleapis.com/oauth2/v3/token", val) |
| 67 | + defer resp.Body.Close() |
| 68 | + if err != nil { |
| 69 | + return nil, err |
| 70 | + } |
| 71 | + tr := &TokenResponse{} |
| 72 | + err = json.NewDecoder(resp.Body).Decode(tr) |
| 73 | + if err != nil { |
| 74 | + return nil, err |
| 75 | + } |
| 76 | + return tr, nil |
| 77 | +} |
| 78 | + |
| 79 | +type KubectlUser struct { |
| 80 | + Name string `yaml:"name"` |
| 81 | + KubeUserInfo *KubeUserInfo `yaml:"user"` |
| 82 | +} |
| 83 | + |
| 84 | +type KubeUserInfo struct { |
| 85 | + AuthProvider *AuthProvider `yaml:"auth-provider"` |
| 86 | +} |
| 87 | + |
| 88 | +type AuthProvider struct { |
| 89 | + APConfig *APConfig `yaml:"config"` |
| 90 | + Name string `yaml:"name"` |
| 91 | +} |
| 92 | + |
| 93 | +type APConfig struct { |
| 94 | + ClientID string `yaml:"client-id"` |
| 95 | + ClientSecret string `yaml:"client-secret"` |
| 96 | + IdToken string `yaml:"id-token"` |
| 97 | + IdpIssuerUrl string `yaml:"idp-issuer-url"` |
| 98 | + RefreshToken string `yaml:"refresh-token"` |
| 99 | +} |
| 100 | + |
| 101 | +type UserInfo struct { |
| 102 | + Email string `json:"email"` |
| 103 | +} |
| 104 | + |
| 105 | +func getUserEmail(accessToken string) (string, error) { |
| 106 | + uri, _ := url.Parse("https://www.googleapis.com/oauth2/v1/userinfo") |
| 107 | + q := uri.Query() |
| 108 | + q.Set("alt", "json") |
| 109 | + q.Set("access_token", accessToken) |
| 110 | + uri.RawQuery = q.Encode() |
| 111 | + resp, err := http.Get(uri.String()) |
| 112 | + defer resp.Body.Close() |
| 113 | + if err != nil { |
| 114 | + return "", err |
| 115 | + } |
| 116 | + ui := &UserInfo{} |
| 117 | + err = json.NewDecoder(resp.Body).Decode(ui) |
| 118 | + if err != nil { |
| 119 | + return "", err |
| 120 | + } |
| 121 | + return ui.Email, nil |
| 122 | +} |
| 123 | + |
| 124 | +func generateUser(email, clientId, clientSecret, idToken, refreshToken string) *KubectlUser { |
| 125 | + return &KubectlUser{ |
| 126 | + Name: email, |
| 127 | + KubeUserInfo: &KubeUserInfo{ |
| 128 | + AuthProvider: &AuthProvider{ |
| 129 | + APConfig: &APConfig{ |
| 130 | + ClientID: clientId, |
| 131 | + ClientSecret: clientSecret, |
| 132 | + IdToken: idToken, |
| 133 | + IdpIssuerUrl: "https://accounts.google.com", |
| 134 | + RefreshToken: refreshToken, |
| 135 | + }, |
| 136 | + Name: "oidc", |
| 137 | + }, |
| 138 | + }, |
| 139 | + } |
| 140 | +} |
| 141 | + |
| 142 | +func main() { |
| 143 | + |
| 144 | + flag.Usage = func() { |
| 145 | + fmt.Fprintf(os.Stderr, "Usage of %s:\n\n", os.Args[0]) |
| 146 | + flag.PrintDefaults() |
| 147 | + } |
| 148 | + |
| 149 | + flag.Parse() |
| 150 | + |
| 151 | + if *version { |
| 152 | + fmt.Printf("k8s-oidc-helper %s\n", Version) |
| 153 | + os.Exit(0) |
| 154 | + } |
| 155 | + |
| 156 | + var gcf *GoogleConfig |
| 157 | + var err error |
| 158 | + if len(*appFile) > 0 { |
| 159 | + gcf, err = readConfig(*appFile) |
| 160 | + if err != nil { |
| 161 | + fmt.Printf("Error reading config file %s: %s\n", *appFile, err) |
| 162 | + os.Exit(1) |
| 163 | + } |
| 164 | + } |
| 165 | + var clientID string |
| 166 | + var clientSecret string |
| 167 | + if gcf != nil { |
| 168 | + clientID = gcf.ClientID |
| 169 | + clientSecret = gcf.ClientSecret |
| 170 | + } else { |
| 171 | + clientID = *clientIDFlag |
| 172 | + clientSecret = *clientSecretFlag |
| 173 | + } |
| 174 | + |
| 175 | + if *openBrowser { |
| 176 | + cmd := exec.Command("open", fmt.Sprintf(oauthUrl, clientID)) |
| 177 | + err = cmd.Start() |
| 178 | + } |
| 179 | + if !*openBrowser || err != nil { |
| 180 | + fmt.Printf("Open this url in your browser: %s\n", fmt.Sprintf(oauthUrl, clientID)) |
| 181 | + } |
| 182 | + |
| 183 | + reader := bufio.NewReader(os.Stdin) |
| 184 | + fmt.Print("Enter the code Google gave you: ") |
| 185 | + code, _ := reader.ReadString('\n') |
| 186 | + code = strings.TrimSpace(code) |
| 187 | + |
| 188 | + tokResponse, err := getTokens(clientID, clientSecret, code) |
| 189 | + if err != nil { |
| 190 | + fmt.Printf("Error getting tokens: %s\n", err) |
| 191 | + os.Exit(1) |
| 192 | + } |
| 193 | + |
| 194 | + email, err := getUserEmail(tokResponse.AccessToken) |
| 195 | + if err != nil { |
| 196 | + fmt.Printf("Error getting user email: %s\n", err) |
| 197 | + os.Exit(1) |
| 198 | + } |
| 199 | + |
| 200 | + userConfig := generateUser(email, clientID, clientSecret, tokResponse.IdToken, tokResponse.RefreshToken) |
| 201 | + output := map[string][]*KubectlUser{} |
| 202 | + output["users"] = []*KubectlUser{userConfig} |
| 203 | + response, err := yaml.Marshal(output) |
| 204 | + if err != nil { |
| 205 | + fmt.Printf("Error marshaling yaml: %s\n", err) |
| 206 | + os.Exit(1) |
| 207 | + } |
| 208 | + fmt.Println("\n# Add the following to your ~/.kube/config") |
| 209 | + fmt.Println(string(response)) |
| 210 | + |
| 211 | +} |
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