It's not clear if this is absolutely necessary or not, but it probably
doesn't hurt. It's not clear if there is a way to read the previous
state before running this. Of course this isn't really thread-safe, so
use at your own risk.
It was non-trivial to do this, so I put it into a library. Strangely I
couldn't directly wrap the ReadPassword function from the
golang.org/x/term package, as it wouldn't unblock for some reason.
This is a big giant patch that implements the AST part of lambdas!
I don't know how Sam is able to understand the AST so well, but he does,
and we're all grateful for it. Most of this code was written by him.
Co-authored-by: Samuel Gélineau <gelisam@gmail.com>
This will probably change up again in the future, but this is what we
need for now to make lambdas work.
Co-authored-by: Samuel Gélineau <gelisam@gmail.com>
These test both graph shape consistency and single value outputs.
Eventually we want to make the graph shape tests more precise, and also
verify specific outputs how it used to be. For now, this is okay.
Co-authored-by: Samuel Gélineau <gelisam@gmail.com>
This adds a new implementation of the function engine that runs the DAG
function graph. This version is notable in that it can run a graph that
changes shape over time. To make changes to the same of the graph, you
must use the new transaction (Txn) system. This system implements a
simple garbage collector (GC) for scheduled removal of nodes that the
transaction system "reverses" out of the graph.
Special thanks to Samuel Gélineau <gelisam@gmail.com> for his help
hacking on and debugging so much of this concurrency work with me.
We should check this for safety. An error is better than a panic. If we
try to set an unexported field, this would panic. We should prevent
being able to even type unify that though!
This returns the type with the arg names we'll actually use. This is
helpful so we can pass values to the right places. We have named edges
so you can actually see what's going on.
Co-authored-by: Samuel Gélineau <gelisam@gmail.com>
This plumbs through the new Output method signature that accepts a table
of function pointers to values and relies on the previous storing of the
function pointers to be used for the lookup right now. This has the
elegant side-effect that Output generation could run in parallel with
the graph engine, as the engine only needs to pause to take a snapshot
of the current values tables.
Co-authored-by: Samuel Gélineau <gelisam@gmail.com>
The Graph signature changes are needed for future function work, and it
also fits in nicely with the need for storing the value pointer for each
function node. These are used to later extract values during the Output
stage.
Sam deserves all of the credit for realizing both of these points and
convincing me to make the change! It worked out great, cheers!
Co-authored-by: Samuel Gélineau <gelisam@gmail.com>
This makes some of the Graph sig changes to prepare the code for proper
functions. The remaining bits will happen later.
Co-authored-by: Samuel Gélineau <gelisam@gmail.com>
If our machine has that pipe busy, don't panic the test. (We do want it
to fail though!)
We're also more careful to check nil object just as a convenience to
help programmers.
A back poke is the deferral or delay of a Process/CheckApply. This is
because we notice that we're not truly ready to CheckApply due to some
timestamp issue. When Process errors, we should accept that, but not
treat it as a success.
The retry and limit "satellite" event loops didn't allow pausing or
resuming, and instead you needed to wait until either was done before
you could pause.
The downside of this patch is that for very fast graph transitions, we
wouldn't be really obeying the limits anymore, however now that we have
per resource kind+name uid, we can persist the limits across graph swaps
if we want to.
Most importantly, this allows us to exit entirely when we're stuck in
one of these satellite loops.
This adds a meta state store that is preserved between graph switches if
the kind and name match. This is useful so that rapid graph changes
don't necessarily reset their retry count if they've only changed one
resource field.
