Vault: Storage consul: upper case letters in service_tags are lowered

[caparisi]

Describe the bug
Value set in consul tags should been stricly the same that defined in service_tags consul storage config.

To Reproduce

1. Setup a consul backend storage with upper case :

storage "consul" {
  address = "<...>:8500"
  path    = "vault"
  service = "vault"
  service_tags = "traefik.enable=true,traefik.frontend.rule=Host:test-vault.mydomain.com"
  token   = "<...>"
}

1. Restart / Unseal your vault
2. Check on Consul UI your vault service, the Host define in vault configuration became host

Expected behavior
All upper case in service_tags should not been converted in low case.

Environment:

• Vault Server Version (retrieve with vault status):

Key                    Value
---                    -----
Seal Type              shamir
Initialized            true
Sealed                 false
Total Shares           5
Threshold              3
Version                1.0.3
Cluster Name           vault-cluster-<...>
Cluster ID             <...>
HA Enabled             true
HA Cluster             https://<...>:8201
HA Mode                standby
Active Node Address    http://<...>:8200

• Vault CLI Version (retrieve with vault version):

Vault v1.0.3 ('85909e3373aa743c34a6a0ab59131f61fd9e8e43')

• Server Operating System/Architecture:

Centos 7
Docker 18.09.3 
Official vault image vault:1.0.3

Vault server configuration file(s):

storage "consul" {
  address = "<...>:8500"
  path    = "vault"
  service = "vault"
  service_tags = "traefik.enable=true,traefik.frontend.rule=Host:test-vault.mydomain.com"
  token   = "<...>"
}
listener "tcp" {
  address           = "0.0.0.0:8200"
  cluster_address   = "0.0.0.0:8201"
  tls_disable       = true
}
default_lease_ttl = "1h"
ui = true
api_addr = "http://<...>:8200"
cluster_addr = "https://<...>:8201"

Additional context
Theses tags are used by a reverse proxy / load balancer TRAEFIK which is case sensitive.

[deniszh]

👍
Faced exact same issue, also with Traefik.

[GabeL7r]

Same issue here.