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https://issues.apache.org/jira/browse/QUARKS-195?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Dale LaBossiere updated QUARKS-195:
-----------------------------------
Description:
Add `TStream.peek(Peek<T>)` and change `Metrics.counter(TStream)` and
`Metrics.rateMeter(TStream)` to use it instead of `pipe()`.
The author of CounterOp and RateMeter implemented the functionality as Peek
Oplets not as Consumer functions. Lacking a TStream.peek(Peek), TStream.pipe()
must be used to add the Peek oplets to the topology.
The runtime treats TStream.peek(Consumer) generated Peek oplets rather
differently than pipe related oplets (added via pipe() or indirectly via
pipe-ish functional methods): see Connector.connect() vs Connector.peek(), and
TStream.peek() returns "this" whereas the addition of pipe oplets returns a new
TStream.
The use of pipe() in this case is partially responsible for the effect reported
in QUARKS-189.
Adding TStream.peek(Peek) enables users/authors of Peek oplets to get the same
peek-ish behavior as their functional peeker brethen. It continues to flesh
out the general ability of API clients to implement and add oplets to the
topology.
The growing number of "oplet" based analogs to the "function" based methods
makes me wonder if the oplet ones should be broken out into another interface
that TStream implements (`OpletTStream`?). It would contain the current
`pipe(Pipe)`, `fanin(FanIn,List)`, `sink(Sink)`, and the new `peek(Peek)`, and
any others that may be needed in the future - e.g., a `split(Split)` and/or
one that can handle multiple iports and oports.
Instead, TStream.pipe() (ConnectorStream.pipe()) could be modified to deal with
Pipe oplet args in the desired manner and document that Pipe oplets receive
this special treatment and that pipe() returns "this" for them instead of a new
TStream. Adding TStream.peek(Peek) seems like a clearer alternative, and
perhaps oplet.core.Peek should not extend Pipe?
was:
Add `TStream.peek(Peek<T>)` and change `Metrics.counter(TStream)` and
`Metrics.rateMeter(TStream)` to use it instead of `pipe()`.
Using pipe() isn't appropriate as these are Peek ops and it's partially
responsible for the effect reported in QUARKS-189. Changing to peek() will
eliminate one of the two extra injected CounterOp and will eliminate the single
extra StreamScope.
The growing number of "oplet" based analogs to the "function" based methods
makes me wonder if the oplet ones should be broken out into another interface
that TStream implements (`OpletTStream`?). It would contain the current
`pipe(Pipe)`, `fanin(FanIn,List)`, `sink(Sink)`, and the new `peek(Peek)`, and
any others that may be needed in the future - e.g., a `split(Split)` and/or
one that can handle multiple iports and oports.
> Metrics.{counter,rateMeter}() shouldn't use TStream.pipe()
> ----------------------------------------------------------
>
> Key: QUARKS-195
> URL: https://issues.apache.org/jira/browse/QUARKS-195
> Project: Quarks
> Issue Type: Bug
> Components: API
> Reporter: Dale LaBossiere
> Assignee: Dale LaBossiere
> Priority: Minor
>
> Add `TStream.peek(Peek<T>)` and change `Metrics.counter(TStream)` and
> `Metrics.rateMeter(TStream)` to use it instead of `pipe()`.
> The author of CounterOp and RateMeter implemented the functionality as Peek
> Oplets not as Consumer functions. Lacking a TStream.peek(Peek),
> TStream.pipe() must be used to add the Peek oplets to the topology.
> The runtime treats TStream.peek(Consumer) generated Peek oplets rather
> differently than pipe related oplets (added via pipe() or indirectly via
> pipe-ish functional methods): see Connector.connect() vs Connector.peek(),
> and TStream.peek() returns "this" whereas the addition of pipe oplets returns
> a new TStream.
> The use of pipe() in this case is partially responsible for the effect
> reported in QUARKS-189.
> Adding TStream.peek(Peek) enables users/authors of Peek oplets to get the
> same peek-ish behavior as their functional peeker brethen. It continues to
> flesh out the general ability of API clients to implement and add oplets to
> the topology.
> The growing number of "oplet" based analogs to the "function" based methods
> makes me wonder if the oplet ones should be broken out into another interface
> that TStream implements (`OpletTStream`?). It would contain the current
> `pipe(Pipe)`, `fanin(FanIn,List)`, `sink(Sink)`, and the new `peek(Peek)`,
> and any others that may be needed in the future - e.g., a `split(Split)`
> and/or one that can handle multiple iports and oports.
> Instead, TStream.pipe() (ConnectorStream.pipe()) could be modified to deal
> with Pipe oplet args in the desired manner and document that Pipe oplets
> receive this special treatment and that pipe() returns "this" for them
> instead of a new TStream. Adding TStream.peek(Peek) seems like a clearer
> alternative, and perhaps oplet.core.Peek should not extend Pipe?
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