This change adds a GRPC endpint to the gomote server which
lists all of the LUCI swarming builders for the project. The
builders names will be used to request the types of gomote
instance requested.

Updates golang/go#61773
For golang/go#61772

Change-Id: I2c6bfb3d251967b8008ba64ee28f2e1c8472df5b
Reviewed-on: https://go-review.googlesource.com/c/build/+/518796
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Carlos Amedee <carlos@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

This change creates a LUCI config client. This client
will be used to query the LUCI configuration service.

Updates golang/go#61773
For golang/go#61772

Change-Id: I1b23facc304e8865be9c900af5b53874840fba47
Reviewed-on: https://go-review.googlesource.com/c/build/+/518797
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Carlos Amedee <carlos@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

This change adds an endpoint to list the swarming builders which are
available for the gomote user to create and instance from.

Updates golang/go#61773
For golang/go#61772

Change-Id: Ic2bd0bb5d9b5866399370197fa543ea949addc31
Reviewed-on: https://go-review.googlesource.com/c/build/+/518798
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Carlos Amedee <carlos@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

If a create is issued without a gomote instance type, the gomote
client will query the gomote server for all available instance types.
This adds the ability to query for swarming builder types.

Updates golang/go#61773
For golang/go#61772

Change-Id: If8d9a2d6b0aa509aafd199ec140659cb7d664308
Reviewed-on: https://go-review.googlesource.com/c/build/+/518799
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Carlos Amedee <carlos@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

The swarmclient requires the per RPC credentials function to be set
even though it isn't used.

For golang/go#61773

Change-Id: I5fe81ef853bfb400212ecfecef3890b53305fb80
Reviewed-on: https://go-review.googlesource.com/c/build/+/537376
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

This change uses the build bucket API to retrieve builder data instead
of the configuration server API. It also changes the desired builder
type to the test only builders.

This also changes the script used to start the buildlet in a swarming
task. Python is already installed on all of the builders. Writing an
OS agnostic script to start the buildlet is preferred in Python.

For golang/go#63781
For golang/go#61773

Change-Id: I6137eac9f0525b6496b45b3ee46e46afaf34afa1
Reviewed-on: https://go-review.googlesource.com/c/build/+/540215
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Carlos Amedee <carlos@golang.org>