Support mixed case consul service tags on consul storage engine (#6483)

* When support for service tags was added, the only way we had to parse
and dedup a list of strings also forced them to be lowercase.  Now there's
another helper func that doesn't smash the case so use that instead.

* update Consul 'service_tag' documentation to include case sensitivity

* added upgrade guide for 1.15

* test for service tags

Co-authored-by: Nick Cabatoff <ncabatoff@hashicorp.com>
Co-authored-by: Peter Wilson <peter.wilson@hashicorp.com>

changelog/6483.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+storage/consul: Consul service registration tags are now case-sensitive.
+```

serviceregistration/consul/consul_service_registration.go

@@ -88,6 +88,10 @@ type serviceRegistration struct {
 
 // NewConsulServiceRegistration constructs a Consul-based ServiceRegistration.
 func NewServiceRegistration(conf map[string]string, logger log.Logger, state sr.State) (sr.ServiceRegistration, error) {
+	if logger == nil {
+		return nil, errors.New("logger is required")
+	}
+
 	// Allow admins to disable consul integration
 	disableReg, ok := conf["disable_registration"]
 	var disableRegistration bool
@@ -168,7 +172,7 @@ func NewServiceRegistration(conf map[string]string, logger log.Logger, state sr.
 
 		logger:              logger,
 		serviceName:         service,
-		serviceTags:         strutil.ParseDedupLowercaseAndSortStrings(tags, ","),
+		serviceTags:         strutil.ParseDedupAndSortStrings(tags, ","),
 		serviceAddress:      serviceAddr,
 		checkTimeout:        checkTimeout,
 		disableRegistration: disableRegistration,

serviceregistration/consul/consul_service_registration_test.go

@@ -10,6 +10,8 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/require"
+
 	"github.com/go-test/deep"
 	"github.com/hashicorp/consul/api"
 	log "github.com/hashicorp/go-hclog"
@@ -563,3 +565,44 @@ func TestConsul_serviceID(t *testing.T) {
 		}
 	}
 }
+
+// TestConsul_NewServiceRegistration_serviceTags ensures that we do not modify
+// the case of any 'service_tags' set by the config.
+// We do expect tags to be sorted in lexicographic order (A-Z).
+func TestConsul_NewServiceRegistration_serviceTags(t *testing.T) {
+	tests := map[string]struct {
+		Tags         string
+		ExpectedTags []string
+	}{
+		"lowercase": {
+			Tags:         "foo,bar",
+			ExpectedTags: []string{"bar", "foo"},
+		},
+		"uppercase": {
+			Tags:         "FOO,BAR",
+			ExpectedTags: []string{"BAR", "FOO"},
+		},
+		"PascalCase": {
+			Tags:         "FooBar, Feedface",
+			ExpectedTags: []string{"Feedface", "FooBar"},
+		},
+	}
+
+	for name, tc := range tests {
+		name := name
+		tc := tc
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+
+			cfg := map[string]string{"service_tags": tc.Tags}
+			logger := logging.NewVaultLogger(log.Trace)
+			be, err := NewServiceRegistration(cfg, logger, sr.State{})
+			require.NoError(t, err)
+			require.NotNil(t, be)
+			c, ok := be.(*serviceRegistration)
+			require.True(t, ok)
+			require.NotNil(t, c)
+			require.Equal(t, tc.ExpectedTags, c.serviceTags)
+		})
+	}
+}

website/content/docs/configuration/service-registration/consul.mdx

@@ -82,8 +82,8 @@ at Consul's service discovery layer.
 - `service` `(string: "vault")` – Specifies the name of the service to register
   in Consul.
 
-- `service_tags` `(string: "")` – Specifies a comma-separated list of tags to
-  attach to the service registration in Consul.
+- `service_tags` `(string: "")` – Specifies a comma-separated list of case-sensitive
+  tags to attach to the service registration in Consul.
 
 - `service_address` `(string: nil)` – Specifies a service-specific address to
   set on the service registration in Consul. If unset, Vault will use what it

website/content/docs/upgrading/upgrade-to-1.15.x.mdx

@@ -0,0 +1,34 @@
+---
+layout: docs
+page_title: Upgrade to Vault 1.15.x - Guides
+description: |-
+  Deprecations, important or breaking changes, and remediation recommendations
+  for anyone upgrading to 1.15.x from Vault 1.14.x.
+---
+
+# Overview
+
+The Vault 1.15.x upgrade guide contains information on deprecations, important
+or breaking changes, and remediation recommendations for anyone upgrading from
+Vault 1.14. **Please read carefully**.
+
+## Consul service registration
+
+As of version 1.15, `service_tags` supplied to Vault for the purpose of [Consul
+service registration](/vault/docs/configuration/service-registration/consul#service_tags)
+will be **case-sensitive**.
+
+In previous versions of Vault tags were converted to lowercase which led to issues,
+for example when tags contained Traefik rules which use case-sensitive method names
+such as `Host()`.
+
+If you previously used Consul service registration tags ignoring case, or relied
+on the lowercase tags created by Vault, then this change may cause unexpected behavior.
+
+Please audit your Consul storage stanza to ensure that you either:
+
+* Manually convert your `service_tags` to lowercase if required
+* Ensure that any system that relies on the tags is aware of the new case-preserving behavior
+
+
+

website/data/docs-nav-data.json

@@ -1945,6 +1945,11 @@
         "title": "Upgrade Plugins",
         "path": "upgrading/plugins"
       },
+      {
+        "title": "Upgrade to 1.15.x",
+        "path": "upgrading/upgrade-to-1.15.x",
+        "hidden": true
+      },
       {
         "title": "Upgrade to 1.14.x",
         "path": "upgrading/upgrade-to-1.14.x"