Using vaultr in packages

vaultr includes some machinery for using vault and vaultr within packages, and within tests in particular. They are designed to work well with testthat but should be easily adapted to work with any other testing framework.

In order to use this, you must set some environment variables:

VAULTR_TEST_SERVER_BIN_PATH must be set to a directory where the vault binary can be found, the path to the vault executable, or to the string auto to find vault on the PATH
VAULTR_TEST_SERVER_PORT can be set to the port where we start creating vault servers (by default this is 18200 but any high port number can be selected - we’ll create servers starting at this port number and incrementing - see below for details)

To create a vault server, run:

srv <- vaultr::vault_test_server()

## ...waiting for Vault to start

As soon as srv goes out of scope and is garbage collected, the vault server will be stopped. So keep srv within the scope of your tests.

This object contains

addr: which is vault’s address
token: a root token for this vault
keys: a vector of unseal keys

By default the vault server is stared in “Dev” server mode in which we run with http (not https), a single unseal key and in-memory storage. It is not suited for any production use.

You can create clients using vaultr::vault_client() and passing in appropriate parameters, but it may be more convenient to use srv$client():

vault <- srv$client()
vault

## <vault: client>
##   Command groups:
##     audit: Interact with vault's audit devices
##     auth: administer vault's authentication methods
##     operator: Administration commands for vault operators
##     policy: Interact with policies
##     secrets: Interact with secret engines
##     token: Interact and configure vault's token support
##     tools: General tools provided by vault
##   Commands:
##     api()
##     delete(path)
##     help()
##     list(path, full_names = FALSE)
##     login(..., method = "token", mount = NULL, renew = FALSE,
##         quiet = FALSE, token_only = FALSE, use_cache = TRUE)
##     read(path, field = NULL, metadata = FALSE)
##     status()
##     unwrap(token)
##     wrap_lookup(token)
##     write(path, data)

vault$list("secret")

## character(0)

By default the client is logged in, but you can pass login = FALSE to create a client that needs to log in:

vault <- srv$client(login = FALSE)

vault$list("secret")

## Error: Have not authenticated against vault

vault$login(token = srv$token)

## Verifying token

vault$list("secret")

## character(0)

You can use $export to export appropriate environment variables to connect to your vault:

srv$export()
Sys.getenv("VAULT_ADDR")

## [1] "http://127.0.0.1:18200"

Sys.getenv("VAULT_TOKEN")

## [1] "2a346bc0-516b-67d8-f337-d28af0aac8d0"

Handling lack of vault gracefully

The vaultr::vault_test_server function takes an argument if_disabled which is a callback function that will be called on failure to start a vault server. This could be for reasons such as:

the user has not opted in by setting VAULTR_TEST_SERVER_BIN_PATH
the binary is not in place
a port could not be opened

By default this calls testthat::skip, which interactively will appear to cause an error but if called within a test_that block in a test will gracefully skip a test

srv <- vaultr::vault_test_server()
## Error: vault is not enabled

Alternatively, provide your own handler:

srv <- vaultr::vault_test_server(if_disabled = message)

In this case, vaultr::vault_test_server will return NULL and you might wrap vault-requiring tests with:

if (!is.null(srv)) {
  # ... vault requiring code here ...
}

All together (and assuming testthat), use of vault within tests might look like this example from the vaultr tests:

test_that("list", {
  srv <- vault_test_server()
  cl <- srv$client()

  cl$write("secret/a", list(key = 1))
  cl$write("secret/b/c", list(key = 2))
  cl$write("secret/b/d/e", list(key = 2))

  expect_setequal(cl$list("secret"), c("a", "b/"))
  expect_setequal(cl$list("secret", TRUE), c("secret/a", "secret/b/"))
  expect_setequal(cl$list("secret/b"), c("c", "d/"))
  expect_setequal(cl$list("secret/b", TRUE), c("secret/b/c", "secret/b/d/"))
})

If you use one vault per test, as here, there’s no need to clean up - we can assume that the vault is empty at the start of the test block and not worry about cleanup at the end. If vault is not enabled this test will be skipped over gracefully.

Installing vault

To develop your package, you will need vault installed; please see the official vault docs for this.

If you use github actions, you can follow the same approach as vaultr itself; add the environment variables VAULTR_TEST_SERVER_BIN_PATH and VAULTR_TEST_SERVER_PORT:

    env:
      ...
      VAULTR_TEST_SERVER_BIN_PATH: auto
      VAULTR_TEST_SERVER_PORT: 18200

then use the eLco/setup-vault action to install a suitable vault binary:

      - uses: eLco/setup-vault@v1

See the vaultr actions for full details.

Rich FitzJohn

2023-11-09

Handling lack of vault gracefully

Installing vault