ipld-eth-server/README.md

# Vulcanize DB

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## About

Vulcanize DB is a set of tools that make it easier for developers to write application-specific indexes and caches for dapps built on Ethereum.

## Dependencies
 - Go 1.11+
 - Postgres 10.6
 - Ethereum Node
   - [Go Ethereum](https://ethereum.github.io/go-ethereum/downloads/) (1.8.23+)
   - [Parity 1.8.11+](https://github.com/paritytech/parity/releases)

## Project Setup

Using Vulcanize for the first time requires several steps be done in order to allow use of the software. The following instructions will offer a guide through the steps of the process:

1. Fetching the project
2. Installing dependencies
3. Configuring shell environment
4. Database setup
5. Configuring synced Ethereum node integration
6. Data syncing

### Installation

In order to fetch the project codebase for local use or modification, install it to your `GOPATH` via:

`go get github.com/vulcanize/vulcanizedb`
`go get gopkg.in/DataDog/dd-trace-go.v1/ddtrace`

Once fetched, dependencies can be installed via `go get` or (the preferred method) at specific versions via `golang/dep`, the prototype golang pakcage manager. Installation instructions are [here](https://golang.github.io/dep/docs/installation.html).

In order to install packages with `dep`, ensure you are in the project directory now within your `GOPATH` (default location is `~/go/src/github.com/vulcanize/vulcanizedb/`) and run:

`dep ensure`

After `dep` finishes, dependencies should be installed within your `GOPATH` at the versions specified in `Gopkg.toml`.

Because we are working with a modified version of the go-ethereum accounts/abi package, after running `dep ensure` you will need to run `git checkout vendor/github.com/ethereum/go-ethereum/accounts/abi` to checkout the modified dependency

Lastly, ensure that `GOPATH` is defined in your shell. If necessary, `GOPATH` can be set in `~/.bashrc` or `~/.bash_profile`, depending upon your system. It can be additionally helpful to add `$GOPATH/bin` to your shell's `$PATH`.

### Setting up the Database
1. Install Postgres
1. Create a superuser for yourself and make sure `psql --list` works without prompting for a password.
1. `createdb vulcanize_public`
1. `cd $GOPATH/src/github.com/vulcanize/vulcanizedb`
1.  Run the migrations: `make migrate HOST_NAME=localhost NAME=vulcanize_public PORT=5432`
    - To rollback a single step: `make rollback NAME=vulcanize_public`
    - To rollback to a certain migration: `make rollback_to MIGRATION=n NAME=vulcanize_public`
    - To see status of migrations: `make migration_status NAME=vulcanize_public`

    * See below for configuring additional environments

### Create a migration file
1. `make new_migration NAME=add_columnA_to_table1`
    - This will create a new timestamped migration file in `db/migrations`
1. Write the migration code in the created file, under the respective `goose` pragma
    - Goose automatically runs each migration in a transaction; don't add `BEGIN` and `COMMIT` statements.

### Configuration
- To use a local Ethereum node, copy `environments/public.toml.example` to
  `environments/public.toml` and update the `ipcPath` and `levelDbPath`.
  - `ipcPath` should match the local node's IPC filepath:
      - For Geth:
        - The IPC file is called `geth.ipc`.
        - The geth IPC file path is printed to the console when you start geth.
        - The default location is:
          - Mac: `<full home path>/Library/Ethereum`
          - Linux: `<full home path>/ethereum/geth.ipc`

      - For Parity:
        - The IPC file is called `jsonrpc.ipc`.
        - The default location is:
          - Mac: `<full home path>/Library/Application\ Support/io.parity.ethereum/`
          - Linux: `<full home path>/local/share/io.parity.ethereum/`

  - `levelDbPath` should match Geth's chaindata directory path.
      - The geth LevelDB chaindata path is printed to the console when you start geth.
      - The default location is:
          - Mac: `<full home path>/Library/Ethereum/geth/chaindata`
          - Linux: `<full home path>/ethereum/geth/chaindata`
      - `levelDbPath` is irrelevant (and `coldImport` is currently unavailable) if only running parity.

- See `environments/infura.toml` to configure commands to run against infura, if a local node is unavailable.
- Copy `environments/local.toml.example` to `environments/local.toml` to configure commands to run against a local node such as [Ganache](https://truffleframework.com/ganache) or [ganache-cli](https://github.com/trufflesuite/ganache-clihttps://github.com/trufflesuite/ganache-cli).

### Start syncing with postgres
Syncs VulcanizeDB with the configured Ethereum node, populating blocks, transactions, receipts, and logs.
This command is useful when you want to maintain a broad cache of what's happening on the blockchain.
1. Start Ethereum node (**if fast syncing your Ethereum node, wait for initial sync to finish**)
1. In a separate terminal start VulcanizeDB:
    - `./vulcanizedb sync --config <config.toml> --starting-block-number <block-number>`

### Alternatively, sync from Geth's underlying LevelDB
Sync VulcanizeDB from the LevelDB underlying a Geth node.
1. Assure node is not running, and that it has synced to the desired block height.
1. Start vulcanize_db
   - `./vulcanizedb coldImport --config <config.toml>`
1. Optional flags:
    - `--starting-block-number <block number>`/`-s <block number>`: block number to start syncing from
    - `--ending-block-number <block number>`/`-e <block number>`: block number to sync to
    - `--all`/`-a`: sync all missing blocks

### Alternatively, sync in "light" mode
Syncs VulcanizeDB with the configured Ethereum node, populating only block headers.
This command is useful when you want a minimal baseline from which to track targeted data on the blockchain (e.g. individual smart contract storage values).
1. Start Ethereum node
1. In a separate terminal start VulcanizeDB:
    - `./vulcanizedb lightSync --config <config.toml> --starting-block-number <block-number>`

## Start full environment in docker by single command

### Geth Rinkeby

make command        | description
------------------- | ----------------
rinkeby_env_up      | start geth, postgres and rolling migrations, after migrations done starting vulcanizedb container
rinkeby_env_deploy  | build and run vulcanizedb container in rinkeby environment
rinkeby_env_migrate | build and run rinkeby env migrations
rinkeby_env_down    | stop and remove all rinkeby env containers

Success run of the VulcanizeDB container require full geth state sync,
attach to geth console and check sync state:

```bash
$ docker exec -it rinkeby_vulcanizedb_geth geth --rinkeby attach
...
> eth.syncing
false
```

If you have full rinkeby chaindata you can move it to `rinkeby_vulcanizedb_geth_data` docker volume to skip long wait of sync.

## Running the Tests
- `createdb vulcanize_private` will create the test db
- `make migrate NAME=vulcanize_private` will run the db migrations
- `make test` will run the unit tests and skip the integration tests
- `make integrationtest` will run the just the integration tests

## Deploying
1. you will need to make sure you have ssh agent running and your ssh key added to it. instructions [here](https://developer.github.com/v3/guides/using-ssh-agent-forwarding/#your-key-must-be-available-to-ssh-agent)
1. `go get -u github.com/pressly/sup/cmd/sup`
1. `sup staging deploy`

## Contract Watchers
Contract watchers work with a light or full sync vDB to fetch raw ethereum data and execute a set of transformations over them, persisting the output.    

A watcher is composed of at least a fetcher and a transformer or set of transformers, where a fetcher is an interface for retrieving raw Ethereum data from some source (e.g. eth_jsonrpc, IPFS)
and a transformer is an interface for filtering through that raw Ethereum data to extract, process, and persist data for specific contracts or accounts. 

### omniWatcher
The `omniWatcher` command is a built-in generic contract watcher. It can watch any and all events for a given contract provided the contract's ABI is available. 
It also provides some state variable coverage by automating polling of public methods, with some restrictions.

This command requires a pre-synced (full or light) vulcanizeDB (see above sections) and currently requires the contract ABI be available on etherscan or provided by the user.   

To watch all events of a contract using a light synced vDB:
    - Execute `./vulcanizedb omniWatcher --config <path to config.toml> --contract-address <contract address>`

Or if you are using a full synced vDB, change the mode to full:
    - Execute `./vulcanizedb omniWatcher --mode full --config <path to config.toml> --contract-address <contract address>`

To watch contracts on a network other than mainnet, use the network flag:
    - Execute `./vulcanizedb omniWatcher --config <path to config.toml> --contract-address <contract address> --network <ropsten, kovan, or rinkeby>`  

To watch events starting at a certain block use the starting block flag:
    - Execute `./vulcanizedb omniWatcher --config <path to config.toml> --contract-address <contract address> --starting-block-number <#>`

To watch only specified events use the events flag:
    - Execute `./vulcanizedb omniWatcher --config <path to config.toml> --contract-address <contract address> --events <EventName1> --events <EventName2>`  

To watch events and poll the specified methods with any addresses and hashes emitted by the watched events utilize the methods flag:  
    - Execute `./vulcanizedb omniWatcher --config <path to config.toml> --contract-address <contract address> --methods <methodName1> --methods <methodName2>`  

To watch specified events and poll the specified method with any addresses and hashes emitted by the watched events:
    - Execute `./vulcanizedb omniWatcher --config <path to config.toml> --contract-address <contract address> --events <EventName1> --events <EventName2> --methods <methodName>`  

To turn on method piping so that values returned from previous method calls are cached and used as arguments in subsequent method calls:  
    - Execute `./vulcanizedb omniWatcher --config <path to config.toml> --piping true --contract-address <contract address> --events <EventName1> --events <EventName2> --methods <methodName>`  

To watch all types of events of the contract but only persist the ones that emit one of the filtered-for argument values:
    - Execute `./vulcanizedb omniWatcher --config <path to config.toml> --contract-address <contract address> --event-args <arg1> --event-args <arg2>`  

To watch all events of the contract but only poll the specified method with specified argument values (if they are emitted from the watched events):  
    - Execute `./vulcanizedb omniWatcher --config <path to config.toml> --contract-address <contract address> --methods <methodName> --method-args <arg1> --method-args <arg2>`  

#### omniWatcher output

Transformed events and polled method results are committed to Postgres in schemas and tables generated according to the contract abi.      

Schemas are created for each contract using the naming convention `<sync-type>_<lowercase contract-address>`
Under this schema, tables are generated for watched events as `<lowercase event name>_event` and for polled methods as `<lowercase method name>_method`  
The 'method' and 'event' identifiers are tacked onto the end of the table names to prevent collisions between methods and events of the same lowercase name    

Example:

Running `./vulcanizedb omniWatcher --config <path to config> --starting-block-number=5197514 --contract-address=0x8dd5fbce2f6a956c3022ba3663759011dd51e73e --events=Transfer --events=Mint --methods=balanceOf` 
watches Transfer and Mint events of the TrueUSD contract and polls its balanceOf method using the addresses we find emitted from those events    

It produces and populates a schema with three tables:

`light_0x8dd5fbce2f6a956c3022ba3663759011dd51e73e.transfer_event`
`light_0x8dd5fbce2f6a956c3022ba3663759011dd51e73e.mint_event`
`light_0x8dd5fbce2f6a956c3022ba3663759011dd51e73e.balanceof_method`

Column ids and types for these tables are generated based on the event and method argument names and types and method return types, resulting in tables such as:

Table "light_0x8dd5fbce2f6a956c3022ba3663759011dd51e73e.transfer_event"

|  Column    |         Type          | Collation | Nullable |                                           Default                                           | Storage  | Stats target | Description  
|:----------:|:---------------------:|:---------:|:--------:|:-------------------------------------------------------------------------------------------:|:--------:|:------------:|:-----------:|
| id         | integer               |           | not null | nextval('light_0x8dd5fbce2f6a956c3022ba3663759011dd51e73e.transfer_event_id_seq'::regclass) | plain    |              |             |
| header_id  | integer               |           | not null |                                                                                             | plain    |              |             |
| token_name | character varying(66) |           | not null |                                                                                             | extended |              |             |
| raw_log    | jsonb                 |           |          |                                                                                             | extended |              |             |
| log_idx    | integer               |           | not null |                                                                                             | plain    |              |             |
| tx_idx     | integer               |           | not null |                                                                                             | plain    |              |             |
| from_      | character varying(66) |           | not null |                                                                                             | extended |              |             |
| to_        | character varying(66) |           | not null |                                                                                             | extended |              |             |
| value_     | numeric               |           | not null |                                                                                             | main     |              |             |


Table "light_0x8dd5fbce2f6a956c3022ba3663759011dd51e73e.balanceof_method"

|   Column   |         Type          | Collation | Nullable |                                            Default                                            | Storage  | Stats target | Description |
|:----------:|:---------------------:|:---------:|:--------:|:-------------------------------------------------------------------------------------------:|:--------:|:------------:|:-----------:|
| id         | integer               |           | not null | nextval('light_0x8dd5fbce2f6a956c3022ba3663759011dd51e73e.balanceof_method_id_seq'::regclass) | plain    |              |             |
| token_name | character varying(66) |           | not null |                                                                                               | extended |              |             |
| block      | integer               |           | not null |                                                                                               | plain    |              |             |
| who_       | character varying(66) |           | not null |                                                                                               | extended |              |             |
| returned   | numeric               |           | not null |                                                                                               | main     |              |             |
  
The addition of '_' after table names is to prevent collisions with reserved Postgres words

### composeAndExecute
The `composeAndExecute` command is used to compose and execute over an arbitrary set of custom transformers.
This is accomplished by generating a Go pluggin which allows our `vulcanizedb` binary to link to external transformers, so
long as they abide by our standard [interfaces](https://github.com/vulcanize/maker-vulcanizedb/tree/compose_and_execute/libraries/shared/transformer).   

This command requires Go 1.11+ and [Go plugins](https://golang.org/pkg/plugin/) only work on Unix based systems.

#### Writing custom transformers
Storage Transformers
   * [Guide](https://github.com/vulcanize/maker-vulcanizedb/blob/compose_and_execute/libraries/shared/factories/storage/README.md)   
   * [Example](https://github.com/vulcanize/maker-vulcanizedb/blob/compose_and_execute/libraries/shared/factories/storage/EXAMPLE.md)   

Event Transformers
   * Guide
   * Example

#### composeAndExecute configuration
A .toml config file is specified when executing the command:
`./vulcanizedb composeAndExecute --config=./environments/config_name.toml`

The config provides information for composing a set of transformers:

```toml
[database]
    name     = "vulcanize_public"
    hostname = "localhost"
    user     = "vulcanize"
    password = "vulcanize"
    port     = 5432

[client]
    ipcPath  = "http://kovan0.vulcanize.io:8545"

[exporter]
    home     = "github.com/vulcanize/vulcanizedb"
    name     = "exampleTransformerExporter"
    save     = false
    transformerNames = [
        "transformer1",
        "transformer2",
        "transformer3",
        "transformer4",
    ]
    [exporter.transformer1]
        path = "path/to/transformer1"
        type = "eth_event"
        repository = "github.com/account/repo"
        migrations = "db/migrations"
    [exporter.transformer2]
        path = "path/to/transformer2"
        type = "eth_event"
        repository = "github.com/account/repo"
        migrations = "db/migrations"
    [exporter.transformer3]
        path = "path/to/transformer3"
        type = "eth_event"
        repository = "github.com/account/repo"
        migrations = "db/migrations"
    [exporter.transformer4]
        path = "path/to/transformer4"
        type = "eth_storage"
        repository = "github.com/account2/repo2"
        migrations = "to/db/migrations"
```
- `home` is the name of the package you are building the plugin for, in most cases this is github.com/vulcanize/vulcanizedb
- `name` is the name used for the plugin files (.so and .go)   
- `save` indicates whether or not the user wants to save the .go file instead of removing it after .so compilation. Sometimes useful for debugging/trouble-shooting purposes.
- `transformerNames` is the list of the names of the transformers we are composing together, so we know how to access their submaps in the exporter map
- `exporter.<transformerName>`s are the sub-mappings containing config info for the transformers
    - `repository` is the path for the repository which contains the transformer and its `TransformerInitializer`
    - `path` is the relative path from `repository` to the transformer's `TransformerInitializer` directory (initializer package).
        - Transformer repositories need to be cloned into the user's $GOPATH (`go get`)
    - `type` is the type of the transformer; indicating which type of watcher it works with (for now, there are only two options: `eth_event` and `eth_storage`)
        - `eth_storage` indicates the transformer works with the [storage watcher](https://github.com/vulcanize/maker-vulcanizedb/blob/compose_and_execute/libraries/shared/watcher/storage_watcher.go)
         that fetches state and storage diffs from an ETH node (instead of, for example, from IPFS)
        - `eth_event` indicates the transformer works with the [event watcher](https://github.com/vulcanize/maker-vulcanizedb/blob/compose_and_execute/libraries/shared/watcher/event_watcher.go)
         that fetches event logs from an ETH node
    - `migrations` is the relative path from `repository` to the db migrations directory for the transformer
- Note: If any of the imported transformers need additional config variables those need to be included as well

This information is used to write and build a Go plugin which exports the configured transformers.
These transformers are loaded onto their specified watchers and executed.

Transformers of different types can be run together in the same command using a single config file or in separate instances using different config files   

The general structure of a plugin .go file, and what we would see built with the above config is shown below

```go
package main

import (
	interface1 "github.com/vulcanize/vulcanizedb/libraries/shared/transformer"
	transformer1 "github.com/account/repo/path/to/transformer1"
	transformer2 "github.com/account/repo/path/to/transformer2"
	transformer3 "github.com/account/repo/path/to/transformer3"
	transformer4 "github.com/account2/repo2/path/to/transformer4"
)

type exporter string

var Exporter exporter

func (e exporter) Export() []interface1.TransformerInitializer, []interface1.StorageTransformerInitializer {
	return []interface1.TransformerInitializer{
		transformer1.TransformerInitializer,
		transformer2.TransformerInitializer,
		transformer3.TransformerInitializer,
	},     []interface1.StorageTransformerInitializer{
		transformer4.StorageTransformerInitializer,
    }
}
```

#### Preparing transformer(s) to work as pluggins for composeAndExecute
To plug in an external transformer we need to:

* Create a [package](https://github.com/vulcanize/mcd_transformers/blob/staging/transformers/bite/initializer/initializer.go) 
that exports a variable `TransformerInitializer` or `StorageTransformerInitializer` that are of type [TransformerInitializer](https://github.com/vulcanize/maker-vulcanizedb/blob/compose_and_execute/libraries/shared/transformer/event_transformer.go#L33)
or [StorageTransformerInitializer](https://github.com/vulcanize/maker-vulcanizedb/blob/compose_and_execute/libraries/shared/transformer/storage_transformer.go#L31), respectively   
* Design the transformers to work in the context of their [event](https://github.com/vulcanize/maker-vulcanizedb/blob/compose_and_execute/libraries/shared/watcher/event_watcher.go#L83)
or [storage](https://github.com/vulcanize/maker-vulcanizedb/blob/compose_and_execute/libraries/shared/watcher/storage_watcher.go#L53) watchers
* Create db migrations to run against vulcanizeDB so that we can store the transformer output
    * Specify migration locations for each transformer in the config with the `exporter.transformer.migrations` fields
    * Do not `goose fix` the transformer migrations

To update a plugin repository with changes to the core vulcanizedb repository, replace the vulcanizedb vendored in the plugin repo (`plugin_repo/vendor/github.com/vulcanize/vulcanizedb`)
with the newly updated version
* The entire vendor lib within the vendored vulcanizedb needs to be deleted (`plugin_repo/vendor/github.com/vulcanize/vulcanizedb/vendor`)
* These complications arise due to this [conflict](https://github.com/golang/go/issues/20481) between `dep` and Go plugins