Make nomulus work locally

[jianglai]

Chose the default transaction manager based on RegistryEnvironment. This
makes it possible to run nomulus on Jetty locally. Tested with the
following:

./gradle :jetty:run -Penvironment=alpha
curl http://localhost:8080/beta.app

The docker image is also updated to take an argument that specifies the
environment. It runs locally as well but the container doesn't get
access to locally stored credentials, so it fails to initialize the
transaction manager.

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This change is 

[jianglai]

Reviewed 7 of 7 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @jianglai)

[jianglai]

Reviewed 3 of 3 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @ptkach)

[ptkach]

Reviewed 4 of 7 files at r1, 2 of 3 files at r2, 2 of 2 files at r3.
Reviewable status: all files reviewed (commit messages unreviewed), 1 unresolved discussion (waiting on @gbrodman and @jianglai)

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jetty/start.sh line 18 at r3 (raw file):

environment=$1
cd /jetty-base
java -jar /usr/local/jetty/start.jar -Dgoogle.registry.environment=${environment:-"alpha"}

It seems a little weird to me that we consider "alpha" to be a local environment. Ideally we probably want to have "local" environment that's dedicated for local runs. Unless there's strong reason not to.

Code quote:

alpha

[jianglai]

Reviewed all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @gbrodman and @ptkach)

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jetty/start.sh line 18 at r3 (raw file):

Previously, ptkach (Pavlo Tkach) wrote…

It seems a little weird to me that we consider "alpha" to be a local environment. Ideally we probably want to have "local" environment that's dedicated for local runs. Unless there's strong reason not to.

Well, it depends on what we mean by "local". Since the workload can run anywhere, the environment here only just determines which config file to load, which in turn decides things like the URL to the Cloud SQL instance for that environment.

So unless we want to set up SQL locally, we really have to point to one of the Cloud environment for us to run the WAR or the image locally.

[ptkach]

Reviewed all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @gbrodman)