ipld-eth-server/documentation/seed-node.md

Seed node commands

Another way that Vulcanizedb can serve as a caching layer for Ethereum is through the use of the syncAndPublish and syncPublishScreenAndServe commands.

Setup

These commands work in conjunction with a state-diffing full Geth node and IPFS.

IPFS

To start, download and install IPFS

go get github.com/ipfs/go-ipfs

cd $GOPATH/src/github.com/ipfs/go-ipfs

make install

If we want to use Postgres as our backing datastore, we need to use the vulcanize fork of go-ipfs. This fork supports the Postgres datastore plugin and has been adjusted to use dep instead of Go modules since Go modules cannot work with un-versioned forks and we need to use an un-versioned fork of go-ipfs-config.

Start by adding the fork and switching over to it:

git remote add vulcanize https://github.com/vulcanize/go-ipfs.git

git fetch vulcanize

git checkout -b postgres_update vulcanize/postgres_update

Now install this fork of ipfs, first be sure to remove any previous installation. It is important to use the below command instead of using make install, as make install will default to using Go modules and this will wreck our dependencies since Go modules cannot work with un-versioned forks.

go install ./cmd/ipfs

Check that is installed properly by running

ipfs

You should see the CLI info/help output.

And now we initialize with the postgresds profile. If ipfs was previously initialized we will need to remove the old profile first. We also need to provide env variables for the postgres connection:

We can either set these manually, e.g.

export IPFS_PGHOST=
export IPFS_PGUSER=
export IPFS_PGDATABASE=
export IPFS_PGPORT=
export IPFS_PGPASSWORD=

And then run the ipfs command

ipfs init --profile=postgresds

Or we can use the pre-made script at GOPATH/src/github.com/ipfs/go-ipfs/misc/utility/ipfs_postgres.sh which has usage:

./ipfs_postgres.sh <IPFS_PGHOST> <IPFS_PGUSER> <IPFS_PGDATABASE>

and will ask us to enter the password, avoiding storing it to an ENV variable.

Once we have initialized ipfs, that is all we need to do with it- we do not need to run a daemon during the subsequent processes.

Geth

For Geth, we currently require a special fork, and we can set this up as follows:

Begin by downloading geth and switching to the vulcanize/rpc_statediffing branch

go get github.com/ethereum/go-ethereum

cd $GOPATH/src/github.com/ethereum/go-ethereum

git remote add vulcanize https://github.com/vulcanize/go-ethereum.git

git fetch vulcanize

git checkout -b rpc_statediffing vulcanize/rpc_statediffing

Now, install this fork of geth (make sure any old versions have been uninstalled/binaries removed first)

make geth

And run the output binary with statediffing turned on:

cd $GOPATH/src/github.com/ethereum/go-ethereum/build/bin

./geth --statediff --statediff.streamblock --ws --syncmode=full

Note: other CLI options- statediff specific ones included- can be explored with ./geth help

The output from geth should mention that it is Starting statediff service and block synchronization should begin shortly thereafter. Note that until it receives a subscriber, the statediffing process does essentially nothing. Once a subscription is received, this will be indicated in the output.

Also in the output will be the websocket url and ipc paths that we will use to subscribe to the statediffing process. The default ws url is "ws://127.0.0.1:8546" and the default ipcPath- on Darwin systems only- is "Users/user/Library/Ethereum/geth.ipc"

Vulcanizedb

There are two commands to choose from:

syncAndPublish

syncAndPublih performs the functions of the seed node- syncing data from Geth, converting them to IPLDs, publishing those IPLDs to IPFS, and creating a local Postgres index to relate their CIDS to useful metadata.

Usage:

./vulcanizedb syncAndPublish --config=<config_file.toml>

The config file for the syncAndPublish command looks very similar to the basic config file

[database]
    name     = "vulcanize_demo"
    hostname = "localhost"
    port     = 5432

[client]
    ipcPath  = "ws://127.0.0.1:8546"
    ipfsPath = "/Users/user/.ipfs"

With an additional field, client.ipcPath, that is either the ws url or the ipc path that Geth has exposed (the url and path output when the geth sync was started), and client.ipfsPath which is the path the ipfs datastore directory.

syncPublishScreenAndServe

syncPublishScreenAndServe does everythin th at syncAndPublish does, plut it opens up an RPC server which exposes an endpoint to allow transformers to subscribe to subsets of the sync-and-published data that are relevant to thier transformations

Usage:

./vulcanizedb syncPublishScreenAndServe --config=<config_file.toml>

The config file for the syncPublishScreenAndServe command has two additional fields and looks like:

[database]
    name     = "vulcanize_demo"
    hostname = "localhost"
    port     = 5432

[client]
    ipcPath  = "ws://127.0.0.1:8546"
    ipfsPath = "/Users/user/.ipfs"

[server]
    ipcPath = "/Users/user/.vulcanize/vulcanize.ipc"
    wsEndpoint = "127.0.0.1:2019"

The additional server.ipcPath and server.wsEndpoint fields are used to set what ipc endpoint and ws url the syncPublishScreenAndServe rpc server will expose itself to subscribing transformers over, respectively.

Subscribing

A transformer can subscribe to the syncPublishScreenAndServe service over its ipc or ws endpoints, when subscribing the transformer specifies which subsets of the synced data it is interested in and the server will forward only these data.

The streamSubscribe command serves as a simple demonstration/example of subscribing to the seed-node feed, it subscribes with a set of parameters defined in the loaded config file, and prints the streamed data to stdout. To build transformers that subscribe to and use seed-node data, the shared/libraries/streamer can be used.

Usage:

./vulcanizedb streamSubscribe --config=<config_file.toml>

The config for streamSubscribe has the subscribe set of parameters, for example:

[subscription]
    path = "ws://127.0.0.1:2019"
    backfill = true
    backfillOnly = false
    startingBlock = 0
    endingBlock = 0
    [subscription.headerFilter]
        off = false
        finalOnly = true
    [subscription.trxFilter]
        off = false
        src = [
            "0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe",
        ]
        dst = [
            "0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe",
        ]
    [subscription.receiptFilter]
        off = false
        topic0s = [
            "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef",
            "0x930a61a57a70a73c2a503615b87e2e54fe5b9cdeacda518270b852296ab1a377"
        ]
    [subscription.stateFilter]
        off = false
        addresses = [
           "0xde0B295669a9FD93d5F28D9Ec85E40f4cb697BAe"
       ]
       intermediateNodes = false
    [subscription.storageFilter]
        off = true
        addresses = [
            "",
            ""
        ]
        storageKeys = [
            "",
            ""
        ]
        intermediateNodes = false

subscription.path is used to define the ws url OR ipc endpoint we will subscribe to the seed-node over (the server.ipcPath or server.wsEndpoint that the seed-node has defined in their config file).

subscription.backfill specifies whether or not the seed-node should look up historical data in its cache and send that to the subscriber, if this is set to false then the seed-node only forwards newly synced/incoming data.

subscription.backfillOnly will tell the seed-node to only send historical data and not stream incoming data going forward.

subscription.startingBlock is the starting block number for the range we want to receive data in.

subscription.endingBlock is the ending block number for the range we want to receive data in; setting to 0 means there is no end/we will continue indefinitely.

subscription.headerFilter has two sub-options: off and finalOnly. Setting off to true tells the seed-node to not send any headers to the subscriber; setting finalOnly to true tells the seed-node to send only canonical headers.

subscription.trxFilter has three sub-options: off, src, and dst. Setting off to true tells the seed-node to not send any transactions to the subscriber; src and dst are string arrays which can be filled with ETH addresses we want to filter transactions for, if they have any addresses then the seed-node will only send transactions that were sent or received by the addresses contained in src and dst, respectively.

subscription.receiptFilter has two sub-options: off and topics. Setting off to true tells the seed-node to not send any receipts to the subscriber; topic0s is a string array which can be filled with event topics we want to filter for, if it has any topics then the seed-node will only send receipts that contain logs which have that topic0.

subscription.stateFilter has three sub-options: off, addresses, and intermediateNodes. Setting off to true tells the seed-node to not send any state data to the subscriber; addresses is a string array which can be filled with ETH addresses we want to filter state for, if it has any addresses then the seed-node will only send state leafs (accounts) corresponding to those account addresses. By default the seed-node only sends along state leafs, if we want to receive branch and extension nodes as well intermediateNodes can be set to true.

subscription.storageFilter has four sub-options: off, addresses, storageKeys, and intermediateNodes. Setting off to true tells the seed-node to not send any storage data to the subscriber; addresses is a string array which can be filled with ETH addresses we want to filter storage for, if it has any addresses then the seed-node will only send storage nodes from the storage tries at those state addresses. storageKeys is another string array that can be filled with storage keys we want to filter storage data for. It is important to note that the storageKeys are the actual keccak256 hashes, whereas the addresses in the addresses fields are the ETH addresses and not their keccak256 hashes that serve as the actual state keys. By default the seed-node only sends along storage leafs, if we want to receive branch and extension nodes as well intermediateNodes can be set to true.