(www/R-gargle) Updated 1.2.0 to 1.4.0

# gargle 1.4.0

## Google Compute Engine

* `credentials_gce(scopes = NULL)` is now equivalent to
  `credentials_gce(scopes =
  "https://www.googleapis.com/auth/cloud-platform")`, i.e. there's an
  even stronger current towards the recommended "cloud-platform"
  scope.

* `credentials_gce(scopes =)` now includes those `scopes` in its
  request to the metadata server for an access token (#216). Note that
  the scopes for a GCE access token are generally pre-determined for
  the instance and its associated service account at creation/launch
  time and these requested `scopes` will have no effect. But this
  seems to do no harm and it is possible that there are contexts where
  this is useful.

* `credentials_gce()` now emits considerably more information when the
  `"gargle_verbosity"` option is set to `"debug"`. For example, it
  reports mismatches between requested scopes and instance scopes and
  between requested scopes and the access token's actual scopes.

* `credentials_gce()` stores the actual scopes of the received access
  token, which can differ from the requested scopes. This is also
  noted when the `"gargle_verbosity"` option is set to `"debug"`.

* The `GceToken` R6 class gains a better `$print()` method that is
  more similar to gargle's treatment of tokens obtained with other
  flows.

## Behaviour in a cloud/server context

* gargle is better able to detect when it's running on Posit Workbench
  or RStudio Server, e.g., in a subprocess.

* `gargle_oauth_client_type()` is a new function that returns either
"installed" or "web".  It returns the value of the new global option
by the same name (`"gargle_oauth_client_type"`), if defined.  If the
option is not defined, returns "web" on RStudio Server, Posit
Workbench, Posit Cloud, or Google Colaboratory and "installed"
otherwise.  In the context of out-of-band (OOB) auth, an "installed"
client type leads to the conventional OOB flow (only available for GCP
projects in testing mode) and a "web" client leads to the new
pseudo-OOB flow.  The option and accessor have been added to cover
contexts other than those mentioned above where it is helpful to
request a "web" client.

* `credentials_user_oauth2()` now works in Google Colaboratory (#140).

## Everything else

* gargle now elicits user input via `readline()`, instead of via
  `utils::menu()`, which is favorable for interacting with the user in
  a Jupyter notebook (#242).

* The roxygen templating functions that wrapper packages can use to
generate standardized documentation around auth have been updated to
reflect gargle's pivot from OAuth "app" to "client".  Changes of note:

  - `PREFIX_auth_configure_description()` crosslinks to `PREFIX_oauth_client()`
    now, not `PREFIX_oauth_app()`. So this assumes the package has indeed
    introduced the `PREFIX_oauth_client()` function (and, presumably, has
    deprecated `PREFIX_oauth_app()`).
  - `PREFIX_auth_configure_params()` gains `client` argument.
  - `PREFIX_auth_configure_params()` deprecates the `app` argument and uses a
    lifecycle badge. It is assumed that the badge SVG is present, which can be
    achieved with `usethis::use_lifecycle()`.
  - `PREFIX_auth_configure_params()` crosslinks to
    `gargle::gargle_oauth_client_from_json()`. The wrapper package therefore
    needs to state a minimum version for gargle, e.g. `gargle (>= 1.3.0)` (or
    higher).

* `credentials_byo_oauth2()` works now for (variations of) service
  account tokens, as intended, not just for user tokens (#250). It
  also emits more information about scopes when the
  `"gargle_verbosity"` option is set to `"debug"`.

# gargle 1.3.0

## (Partial) deprecation out-of-band (OOB) auth flow

On February 16, 2022, Google announced the gradual deprecation of the
out-of-band (OOB) OAuth flow.  OOB **still works** if the OAuth client
is associated with a GCP project that is in testing mode and this is
not going away.  But OOB is no longer supported for projects in
production mode.  To be more accurate, some production-mode projects
have gotten an extension to permit the use of OOB auth for a bit
longer, but that's just a temporary reprieve.

The typical user who will (eventually) be impacted is:

* Using R via RStudio Server, Posit Workbench, or Posit Cloud.
* Using tidyverse packages such as googledrive, googlesheets4, or bigrquery.
* Relying on the built-in OAuth client. Importantly, this client is associated
  with a GCP project that is in production mode.

The phased deprecation of OOB is nearly complete and we expect
conventional OOB to stop working with the built-in tidyverse OAuth
client on February 1, 2023, at the latest.

**In preparation for this, gargle has gained support for a new flow,
which we call pseudo-OOB (in contrast to conventional OOB)**.  The
pseudo-OOB flow is triggered when `use_oob = TRUE` (an existing
convention in gargle and gargle-using packages) and the configured
OAuth client is of "Web application" type.  The
gargle/googledrive/googlesheets4/bigrquery packages should now default
to a "Web application" client on RStudio Server, Posit Workbench and
Posit Cloud, leading the user through the pseudo-OOB flow.  Other than
needing to re-auth once, affected users should still find that things
"just work".

Read the `vignette("auth-from-web")` for more.

## gargle-specific notion of OAuth client

`gargle_oauth_client()` is a new constructor for an S3 class by the same name.
There are two motivations:

  - To adjust to Google's deprecation of conventional OOB and to support
    gargle's new pseudo-OOB flow, it is helpful for gargle to know whether an
    OAuth client ID is of type "Web application" or "Desktop app". That means we
    need a Google- and gargle-specific notion of an OAuth client, so we can
    introduce a `type` field.
  - A transition from httr to httr2 is on the horizon, so it makes sense to
    look more toward `httr2:oauth_client()` than to `httr::oauth_app()`.
    gargle's vocabulary is generally shifting towards "client" and away from
    "app".

`oauth_app_from_json()` has therefore been (soft) deprecated, in favor
of a new function `gargle_oauth_client_from_json()`, which is the
preferred way to instantiate an OAuth client, since the downloaded
JSON conveys the client type and redirect URI(s).  As a bridging
measure, `gargle_oauth_client` currently inherits from httr's
`oauth_app`, but this probably won't be true in the long-term.

`gargle_client(type =)` replaces `gargle_app()`.

## Google Compute Engine and Google Kubernetes Engine

`credentials_gce()` no longer asks the user about initiating an OAuth
cache, which is not relevant to that flow (#221).

`gce_instance_service_accounts()` is a newly exported utility that
exposes the service accounts available from the metadata server for
the current instance (#234).

The global option `"gargle.gce.timeout"` is newly documented in
`credentials_gce()`.  This controls the timeout, in seconds, for
requests to the metadata server.  The default value (or strategy) for
setting this should often suffice, but the option exists for those
with an empirical need to increase the timeout (#186, #195).

`vignette("non-interactive-auth")` has a new section "Workload
Identity on Google Kubernetes Engine (GKE)" that explains how gargle
supports the use of workload identity for applications running on
GKE. This is the recommended method of auth in R code running on GKE
that needs to access other Google Cloud services, such as the BigQuery
API (#197, #223, @MarkEdmondson1234).

## Credential function registry

It's gotten a bit easier to work with the credential registry.
The primary motivation is that, for example, on Google Compute Engine, you might
actually want to suppress auth with the default service account and auth as a
normal user instead.
This is especially likely to come up with gmailr / the Gmail API.

* The credential-fetcher `credentials_byo_oauth2()` has been moved to the very
  beginning of the default registry. The logic is that a user who has specified
  a non-`NULL` value of `token` must mean business and does not want automagic
  auth methods like ADC or GCE to be tried before using their `token`
  (#187, #225).

* The `...` in `cred_funs_all()` are now
  [dynamic dots](https://rlang.r-lib.org/reference/dyn-dots.html) (#224).

* Every registered credential function must have a unique name now.
  This is newly enforced by `cred_funs_add()` and `cred_funs_set()` (#224).

* `cred_funs_list_default()` is a new function that returns gargle's default
  list of credential functions (#226).

* `cred_funs_add(cred_fun = NULL)` is now available to remove a credential
  function from the registry (#224).

* `with_cred_funs()` and `local_cred_funs()` are new helpers for making narrowly
  scoped changes to the registry (#226).

* The `ls` argument of `cred_funs_set()` has been renamed to `funs` (#226).

* In general, credential registry functions now return the current registry,
  invisibly (#224).

# gargle 1.2.1

* Help files below `man/` have been re-generated, so that they give
  rise to valid HTML5. (This is the impetus for this release, to keep
  the package safely on CRAN.)

* We have switched to newer oauth2.googleapis.com-based OAuth2 URIs,
  moving away from the accounts.google.com and googleapis.com/oauth2
  equivalents.

* `credentials_gce()` no longer validates the requested scopes against
instance scopes.  In practice, it's easy for this check to be more of
a nuisance than a help (#161, #185 @craigcitro).

* `request_retry()` retries for an expanded set of HTTP codes: 408,
  429, 500, 502, 503. Previously, retries were limited to 429 (#169).

## Dependency changes

* The minimum versions of rlang and testthat have been bumped. The
  motivation is to exploit and adapt to the changes to the display of
  error messages.


(mef)