eth, internal/web3ext: add optional first and last arguments to the admin_exportChain RPC.

[ryanschneider]

I was playing w/ the block importing/exporting logic today to get a better understanding of how it worked, and realized that the only way currently to export blocks is to use admin_exportChain (which exports the entire chain) or geth export (which requires the node to be stopped since only one process can have access to the leveldb).

So, this simply adds a new admin_exportBlocks RPC that takes the same arguments as geth export but can be done while the node is running.

[karalabe]

I don't see a reason for adding a new method for this. You can add 2 more optional parameters to the existing admin_exportChain (*uint64 types). If they are nil, you default to the current behavior, if not, use the specified range.

[ryanschneider]

Ah ok I didn’t realize that pointers were interpreted as optionals. Do I need to do anything special in web3ext to support this?

…

On Thu, Sep 26, 2019 at 4:47 AM Péter Szilágyi ***@***.***> wrote: I don't see a reason for adding a new method for this. You can add 2 more optional parameters to the existing admin_exportChain (*uint64 types). — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#20107?email_source=notifications&email_token=AAANCEBHFCWFK5FEHQBD663QLSOMRA5CNFSM4IY3K5WKYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOD7VJC5A#issuecomment-535466356>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAANCEBKHOCRZXUFZLRAKCDQLSOMRANCNFSM4IY3K5WA> .

[ryanschneider]

Ok @karalabe I've force pushed 353347c which adds the first and last as arguments to the admin_exportChain RPC. As far as I can tell I don't need to do anything special to support them as optional arguments, all cases worked as expected for me with the console:

$ ~/go/src/github.com/ethereum/go-ethereum/build/bin/geth attach /Users/ryans/Library/Ethereum/goerli/geth.ipc
Welcome to the Geth JavaScript console!

instance: Geth/v1.9.6-unstable-93ea2c70-20190920/darwin-amd64/go1.13
at block: 1396301 (Tue, 01 Oct 2019 13:51:27 PDT)
 datadir: /Users/ryans/Library/Ethereum/goerli
 modules: admin:1.0 clique:1.0 debug:1.0 eth:1.0 miner:1.0 net:1.0 personal:1.0 rpc:1.0 txpool:1.0 web3:1.0

> admin.exportChain("/tmp/all.gz", 1)
Error: first and last must be included or omitted as a pair
    at web3.js:3143:20
    at web3.js:6347:15
    at web3.js:5081:36
    at <anonymous>:1:1

> admin.exportChain("/tmp/all.gz", 5,2)
Error: export failed: first (5) is greater than last (2)
    at web3.js:3143:20
    at web3.js:6347:15
    at web3.js:5081:36
    at <anonymous>:1:1

> admin.exportChain("/tmp/1332997.gz", 1332997, 1333000)
true

[karalabe]

Why not let only the first be specified and from that point onward export the entire chain till head? Seems more robust to me.

[ryanschneider]

You mean when first is set and last is nil? Ya, I can see that being useful. I'll update the PR to support that.

[ryanschneider]

Ok, force pushed 947c62b which supports this behavior:

> admin.exportChain("/tmp/1332997.gz", 1332997, 1333000)
true
> admin.exportChain("/tmp/latest.gz", 1724972)
true
> admin.exportChain("/tmp/bad.gz", null, 1333000)
Error: last cannot be specified without first
    at web3.js:3143:20
    at web3.js:6347:15
    at web3.js:5081:36
    at <anonymous>:1:1