some options have default that are best described in prose, such as
defaults that depend on the system stateVersion, defaults that are
derivations specific to the surrounding context, or those where the
expression is much longer and harder to understand than a simple text
snippet.
Instead of requiring the user to bundle the certificate and private
key into a single file, provide separate options for them. This is
more in line with most other modules.
`install` copies the files before setting their mode, so there could
be a breif window where the secrets are readable by other users
without a strict umask.
Feeding `psql` the password on the command line leaks it through the
`psql` process' `/proc/<pid>/cmdline` file. Using `echo` to put the
command in a file and then feeding `psql` the file should work around
this, since `echo` is a bash builtin and thus shouldn't spawn a new
process.
Using `replace-literal` to insert secrets leaks the secrets through
the `replace-literal` process' `/proc/<pid>/cmdline`
file. `replace-secret` solves this by reading the secret straight from
the file instead, which also simplifies the code a bit.
This reverts commit d9e18f4e7f.
This change is broken, since it doesn't configure the proper database
username in keycloak when provisioning a local database with a custom
username. Its intended behavior is also potentially confusing and
dangerous, so rather than fixing it, let's revert to the old one.
