Added new plugin type: PluginScoreLedger

[wolneykien]

With a PluginScoreLedger plugin it is now possible to replace the
default BitSwap decision logic with a different one. The plugin
support depends on the experimental BitSwap option WithScoreLedger
— see 80c1a81b63e5 and related commits in the go-bitswap project
and also ebf11a6556cc commit in the go-ipfs-config project.

A map of score ledgers and new RegisterScoreLedger function were
added to core/node/core.go in order to support score ledger
injection. The selection of the particular ledger is now possible with
enchanced OnlineExchange() function accepting the name of the
ledger ("" is used for the default behavior). It is configured with
Experimental.WithScoreLedger configuration option.

In order to check this modifications and plugin loading two new tests
were added to test/integration package: TestScoreLedgerNotLoaded
and TestScoreLedgerLoadStartStop. To minimize code duplication I've
decided to slightly modify the core/mock/mock.go adding new
NewMockNodeWithConfig() function there. The code that loads and
injects plugin objects is placed in the plugins_common_test.go to
help implementing other plugin tests.

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[wolneykien]

I've also issued ipfs/go-bitswap#430 — the corresponding modification to BitSwap and ipfs/go-ipfs-config#109 — the corresponding modification to the Config.

[wolneykien]

I see that 2 sharness tests have failed due to some expectations in stat0 and stat1 files. But I don't know how to see the actual content of that files.

[aschmahmann]

I see that 2 sharness tests have failed due to some expectations in stat0 and stat1 files. But I don't know how to see the actual content of that files.

If you run the individual sharness tests manually on your machine (e.g. run make test_sharness_deps in the go-ipfs folder, and then `./t0125-twonode -v [note, you can add -i to terminate the test on first error]) then when the test ends there should be a trash folder where you can examine the files.

Take a look at https://github.com/ipfs/go-ipfs/tree/master/test/sharness for more info

[wolneykien]

If you run the individual sharness tests manually on your machine (e.g. run make test_sharness_deps in the go-ipfs folder, and then `./t0125-twonode -v [note, you can add -i to terminate the test on first error]) then when the test ends there should be a trash folder where you can examine the files.

Thanks, @aschmahmann . The twonode test seems to be unstable: in the first run it said "failed 8 among 63", but "passed all 63 test(s)" in the second run.

[wolneykien]

Just have synced this branch with go-ipfs/master and it has passed sharness on my node.

[aschmahmann]

@wolneykien the currently supported plugins are:

• Datastore
• Tracer
• IPLD
• Daemon
• DaemonInternal

Adding a specific plugin for one option type in Bitswap seems like overkill to me, and would open the door to adding new plugins for many many more features. The ones we have so far have been useful for many community projects.

You could accomplish what you're looking for by just building go-ipfs as a library and passing in a custom Bitswap constructor now that your Bitswap PR has landed. You may also be able to get away with a DaemonInternal plugin.

If neither of the above options are suitable for your use case, then we can investigate what makes the most sense.

[wolneykien]

Adding a specific plugin for one option type in Bitswap seems like overkill to me,

May be you're right. Now, I'm not sure about a specific plugin type. However, I think it would be nice to have a way to pass that (and any other!) option to Bitswap from an ordinary plugin, say, from a Daemon plugin, isn't it?

You could accomplish what you're looking for by just building go-ipfs as a library

Thanks, that seems to be a good idea!

You may also be able to get away with a DaemonInternal plugin.

Yes. Anyway, for my current experiments I need to access the P2P Host interface that is inaccessible from CoreAPI.

[aschmahmann]

@wolneykien the DaemonInternal plugin gives you access to the *IpfsNode which has access to the libp2p host unlike the Daemon plugin which only gives you access to the CoreAPI.

I've also filed #7653 and #7652 which I think are relevant to the types of plugins you're asking for.

If you got the go-ipfs as a library route you might benefit from looking at #7602 which is probably the easiest way to get at Bitswap options until something like #7652 lands.

[wolneykien]

#7653 and #7652 sound great! Thanks.