There's a fair bit of clean up in here, but the meat is:
* Allocate the language runtime gRPC client connection on the
goroutine that will use it; this eliminates race conditions.
* The biggie: there *appears* to be a bug in gRPC's implementation
on Linux, where it doesn't implement WaitForReady properly. The
behavior I'm observing is that RPC calls will not retry as they
are supposed to, but will instead spuriously fail during the RPC
startup. To work around this, I've added manual retry logic in
the shared plugin creation function so that we won't even try
to use the client connection until it is in a well-known state.
pulumi/pulumi-fabric#337 tracks getting to the bottom of this and,
ideally, removing the work around.
The other minor things are:
* Separate run.js into its own module, so it doesn't include
index.js and do a bunch of random stuff it shouldn't be doing.
* Allow run.js to be invoked without a --monitor. This makes
testing just the run part of invocation easier (including
config, which turned out to be super useful as I was debugging).
* Tidy up some messages.
This change closes the gRPC client connections, as they keep the
Node.js message loop alive on Linux (but, strangely, not Mac;
regardless, a good thing to do anyway...)
This change adds the ability to perform runtime logging, including
debug logging, that wires up to the Pulumi Fabric engine in the usual
ways. Most stdout/stderr will automatically go to the right place,
but this lets us add some debug tracing in the implementation of the
runtime itself (and should come in handy in other places, like perhaps
the Pulumi Framework and even low-level end-user code).
The organization of packages underneath lib/ breaks the easy consumption
of submodules, a la
import {FileAsset} from "@pulumi/pulumi-fabric/asset";
We will go back to having everything hanging off the module root directory.
This change introduces the notion of a "dry run" into the property
serialization logic, since this controls whether we wait for dependent
linked property values to arrive or not. It also changes the test
harness to run all tests both ways: once in planning mode (when properties
will show up as "unknown" and the second time in deployment mode (when
properties will have settled to their final values).
This is the initial step towards redefining Lumi as a library that runs
atop vanilla Node.js/V8, rather than as its own runtime.
This change is woefully incomplete but this includes some of the more
stable pieces of my current work-in-progress.
The new structure is that within the sdk/ directory we will have a client
library per language. This client library contains the object model for
Lumi (resources, properties, assets, config, etc), in addition to the
"language runtime host" components required to interoperate with the
Lumi resource monitor. This resource monitor is effectively what we call
"Lumi" today, in that it's the thing orchestrating plans and deployments.
Inside the sdk/ directory, you will find nodejs/, the Node.js client
library, alongside proto/, the definitions for RPC interop between the
different pieces of the system. This includes existing RPC definitions
for resource providers, etc., in addition to the new ones for hosting
different language runtimes from within Lumi.
These new interfaces are surprisingly simple. There is effectively a
bidirectional RPC channel between the Lumi resource monitor, represented
by the lumirpc.ResourceMonitor interface, and each language runtime,
represented by the lumirpc.LanguageRuntime interface.
The overall orchestration goes as follows:
1) Lumi decides it needs to run a program written in language X, so
it dynamically loads the language runtime plugin for language X.
2) Lumi passes that runtime a loopback address to its ResourceMonitor
service, while language X will publish a connection back to its
LanguageRuntime service, which Lumi will talk to.
3) Lumi then invokes LanguageRuntime.Run, passing information like
the desired working directory, program name, arguments, and optional
configuration variables to make available to the program.
4) The language X runtime receives this, unpacks it and sets up the
necessary context, and then invokes the program. The program then
calls into Lumi object model abstractions that internally communicate
back to Lumi using the ResourceMonitor interface.
5) The key here is ResourceMonitor.NewResource, which Lumi uses to
serialize state about newly allocated resources. Lumi receives these
and registers them as part of the plan, doing the usual diffing, etc.,
to decide how to proceed. This interface is perhaps one of the
most subtle parts of the new design, as it necessitates the use of
promises internally to allow parallel evaluation of the resource plan,
letting dataflow determine the available concurrency.
6) The program exits, and Lumi continues on its merry way. If the program
fails, the RunResponse will include information about the failure.
Due to (5), all properties on resources are now instances of a new
Property<T> type. A Property<T> is just a thin wrapper over a T, but it
encodes the special properties of Lumi resource properties. Namely, it
is possible to create one out of a T, other Property<T>, Promise<T>, or
to freshly allocate one. In all cases, the Property<T> does not "settle"
until its final state is known. This cannot occur before the deployment
actually completes, and so in general it's not safe to depend on concrete
resolutions of values (unlike ordinary Promise<T>s which are usually
expected to resolve). As a result, all derived computations are meant to
use the `then` function (as in `someValue.then(v => v+x)`).
Although this change includes tests that may be run in isolation to test
the various RPC interactions, we are nowhere near finished. The remaining
work primarily boils down to three things:
1) Wiring all of this up to the Lumi code.
2) Fixing the handful of known loose ends required to make this work,
primarily around the serialization of properties (waiting on
unresolved ones, serializing assets properly, etc).
3) Implementing lambda closure serialization as a native extension.
This ongoing work is part of pulumi/pulumi-fabric#311.
