Merge branch 'master' into issue-657-default-registration-address

CHANGELOG.md

@@ -1,5 +1,21 @@
 ## Changelog
 
+### Unreleased
+
+#### Improvements
+
+* [PR #620](https://github.com/fabiolb/fabio/pull/620): Read Vault token from file
+
+  The new `vaultfetchtoken` option for the vault and vault-pki certificate
+  sources can be used to load Vault tokens from environment variables other
+  than `VAULT_TOKEN` and from files on disk. fabio will automatically notice
+  when file contents change and start using new tokens.
+
+  This improves integration with [Nomad](https://www.nomadproject.io/docs/job-specification/vault.html)
+  and the [Vault Agent](https://www.vaultproject.io/docs/agent/).
+
+  Thanks to [@murphymj25](https://github.com/murphymj25) for the patch.
+
 ### [v1.5.11](https://github.com/fabiolb/fabio/releases/tag/v1.5.11) - 25 Feb 2019
 
 #### Breaking Changes

cert/source.go

@@ -70,15 +70,15 @@ func NewSource(cfg config.CertSource) (Source, error) {
 			ClientCAPath: cfg.ClientCAPath,
 			CAUpgradeCN:  cfg.CAUpgradeCN,
 			Refresh:      cfg.Refresh,
-			Client:       DefaultVaultClient,
+			Client:       NewVaultClient(cfg.VaultFetchToken),
 		}, nil
 	case "vault-pki":
 		src := NewVaultPKISource()
 		src.CertPath = cfg.CertPath
 		src.ClientCAPath = cfg.ClientCAPath
 		src.CAUpgradeCN = cfg.CAUpgradeCN
 		src.Refresh = cfg.Refresh
-		src.Client = DefaultVaultClient
+		src.Client = NewVaultClient(cfg.VaultFetchToken)
 		return src, nil
 
 	default:

cert/vault_client.go

@@ -3,7 +3,9 @@ package cert
 import (
 	"encoding/json"
 	"errors"
+	"io/ioutil"
 	"log"
+	"os"
 	"strings"
 	"sync"
 	"time"
@@ -14,20 +16,45 @@ import (
 // vaultClient wraps an *api.Client and takes care of token renewal
 // automatically.
 type vaultClient struct {
-	addr  string // overrides the default config
-	token string // overrides the VAULT_TOKEN environment variable
+	addr             string // overrides the default config
+	token            string // overrides the VAULT_TOKEN environment variable
+	fetchVaultToken  string
+	prevFetchedToken string
 
 	client *api.Client
 	mu     sync.Mutex
 }
 
+func NewVaultClient(fetchVaultToken string) *vaultClient {
+	return &vaultClient{
+		fetchVaultToken: fetchVaultToken,
+	}
+}
+
 var DefaultVaultClient = &vaultClient{}
 
 func (c *vaultClient) Get() (*api.Client, error) {
 	c.mu.Lock()
 	defer c.mu.Unlock()
-
 	if c.client != nil {
+		if c.fetchVaultToken != "" {
+			token := strings.TrimSpace(getVaultToken(c.fetchVaultToken))
+			if token != c.prevFetchedToken {
+				log.Printf("[DEBUG] vault: token has changed, setting new token")
+				// did we get a wrapped token?
+				resp, err := c.client.Logical().Unwrap(token)
+				switch {
+				case err == nil:
+					log.Printf("[INFO] vault: Unwrapped token %s", token)
+					c.client.SetToken(resp.Auth.ClientToken)
+				case strings.HasPrefix(err.Error(), "no value found at"):
+					// not a wrapped token
+				default:
+					return nil, err
+				}
+				c.prevFetchedToken = token
+			}
+		}
 		return c.client, nil
 	}
 
@@ -39,16 +66,22 @@ func (c *vaultClient) Get() (*api.Client, error) {
 	if c.addr != "" {
 		conf.Address = c.addr
 	}
-
 	client, err := api.NewClient(conf)
 	if err != nil {
 		return nil, err
 	}
 
+	if c.fetchVaultToken != "" {
+		token := strings.TrimSpace(getVaultToken(c.fetchVaultToken))
+		log.Printf("[DEBUG] vault: fetching initial token")
+		if token != c.prevFetchedToken {
+			c.token = token
+			c.prevFetchedToken = token
+		}
+	}
 	if c.token != "" {
 		client.SetToken(c.token)
 	}
-
 	token := client.Token()
 	if token == "" {
 		return nil, errors.New("vault: no token")
@@ -132,3 +165,34 @@ func (c *vaultClient) keepTokenAlive() {
 		timer.Reset(ttl / 2)
 	}
 }
+
+func getVaultToken(c string) string {
+	var token string
+	c = strings.TrimSpace(c)
+	cArray := strings.SplitN(c, ":", 2)
+	if len(cArray) < 2 {
+		log.Printf("[WARN] vault: vaultfetchtoken not properly set")
+		return token
+	}
+	if cArray[0] == "file" {
+		b, err := ioutil.ReadFile(cArray[1]) // just pass the file name
+		if err != nil {
+			log.Printf("[WARN] vault: Failed to fetch token from  %s", c)
+		} else {
+			token = string(b)
+			log.Printf("[DEBUG] vault: Successfully fetched token from %s", c)
+			return token
+		}
+	} else if cArray[0] == "env" {
+		token = os.Getenv(cArray[1])
+		if len(token) == 0 {
+			log.Printf("[WARN] vault: Failed to fetch token from  %s", c)
+		} else {
+			log.Printf("[DEBUG] vault: Successfully fetched token from %s", c)
+			return token
+		}
+	} else {
+		log.Printf("[WARN] vault: vaultfetchtoken not properly set")
+	}
+	return token
+}

config/config.go

@@ -22,14 +22,15 @@ type Config struct {
 }
 
 type CertSource struct {
-	Name         string
-	Type         string
-	CertPath     string
-	KeyPath      string
-	ClientCAPath string
-	CAUpgradeCN  string
-	Refresh      time.Duration
-	Header       http.Header
+	Name            string
+	Type            string
+	CertPath        string
+	KeyPath         string
+	ClientCAPath    string
+	CAUpgradeCN     string
+	Refresh         time.Duration
+	Header          http.Header
+	VaultFetchToken string
 }
 
 type Listen struct {

config/load.go

@@ -577,6 +577,8 @@ func parseCertSource(cfg map[string]string) (c CertSource, err error) {
 				return CertSource{}, err
 			}
 			c.Refresh = d
+		case "vaultfetchtoken":
+			c.VaultFetchToken = v
 		case "hdr":
 			p := strings.SplitN(v, ": ", 2)
 			if len(p) != 2 {

fabio.properties

@@ -114,8 +114,9 @@
 # automatic refreshing set 'refresh' to zero.
 #
 # The path to vault must be provided in the VAULT_ADDR environment
-# variable. The token must be provided in the VAULT_TOKEN environment
-# variable.
+# variable. The token can be provided in the VAULT_TOKEN environment
+# variable, or provided by using the Vault fetch token option.  By default the
+# token is loaded once from the VAULT_TOKEN environment variable.  See Vault PKI for details.
 #
 #   cs=<name>;type=vault;cert=secret/fabio/certs
 #
@@ -137,6 +138,12 @@
 # and re-issue them 24 hours before they expire. The CA for client
 # authentication is expected to be stored at secret/fabio/client-certs.
 #
+# 'vaultfetchtoken' enables fetching the vault token from a file on the filesystem or an environment
+# variable at the Vault refresh interval.  If fetching the token from a file the 'file:[path]' syntax should be used,
+# if fetching the token from an env variable, the 'env:[ENV]' syntax should be used.
+#
+#  cs=<name>;type=vault;cert=secret/fabio/certs;vaultfetchtoken=env:VAULT_TOKEN
+#
 # Common options
 #
 # All certificate stores support the following options: