* #9 Implement routes to list, get and delete execution environments.
A refactoring was required to introduce the ExecutionEnvironment interface.
* Fix MR comments, linting issues and bug that lead to e2e test failure
* Add e2e tests
* Add unit tests
We previously didn't really had any structure in our project apart
from creating a new folder for each package in our project root.
Now that we have accumulated some packages, we use the well-known
Golang project layout in order to clearly communicate our intent
with packages. See https://github.com/golang-standards/project-layout
We now store the mapped ports returned by Nomad locally in our runner
struct and return them when requesting the runner. The returned ip
address is in most Nomad setups not reachable from external users.
To be able to restore the runner timeouts even after a Poseidon restart,
the timeout is stored in the Nomad metadata. The timeout will restart,
but at least the runner will be returned at all.
By removing runners after a specified timeout they no longer stay
around indefinitely and block Nomads capacities. The timeout can be set
individually per runner when requesting the provide route. If it is set
to 0, the runner is never removed automatically.
The timeout is reset when activity is detected. Currently that is when
something gets executed or the filesystem gets modified.
ChannelReceivesSomething (formerly WaitForChannel) originally was
located in the helpers package.
This move was done to remove a cyclic dependency with the nomand package.
When running an execution, Nomad continuously reads from the stdin
reader. Because the readers we implemented (codeOceanToRawReader and
nullReader) return zero if there is no input available, this leads to
busy waiting and a high CPU load on Poseidon. By waiting indefinitely in
case of the nullReader and for at least one byte on case of the
codeOceanToRawReader before returning, we prevent this issue.
As we can't control which allocations are destroyed when downscaling a job, we decided
to use Nomad jobs as our runners. Thus for each runner we prewarm for an environment,
a corresponding job is created in Nomad. We create a default job that serves as a template
for the runners. Using this, already existing execution environments can easily be restored,
once Poseidon is restarted.
For unit tests, this mocks the runners Execute method with a
customizable function that operates on the request, streams and exit
channel to simulate a real execution.
End-to-end tests are moved to the tests/e2e_tests folder. The tests
folder allows us to have shared helper functions for all tests in a
separate package (tests) that is not included in the non-test build.
This also adds one second of delay before each end-to-end test case by
using the TestSetup method of suite. By slowing down test execution,
this gives Nomad time to create new allocations when a test requested a
runner. Another solution could be to increase the scale of the job to
have enough allocations for all end-to-end tests.
Co-authored-by: Maximilian Paß <maximilian.pass@student.hpi.uni-potsdam.de>
This enables executing commands in runners and forwarding input and
output between the runner and the websocket to the client.
Co-authored-by: Maximilian Paß <maximilian.pass@student.hpi.uni-potsdam.de>
