hermez-node/README.md

# hermez-node [![Go Report Card](https://goreportcard.com/badge/github.com/hermeznetwork/hermez-node)](https://goreportcard.com/report/github.com/hermeznetwork/hermez-node) [![Test Status](https://github.com/hermeznetwork/hermez-node/workflows/Test/badge.svg)](https://github.com/hermeznetwork/hermez-node/actions?query=workflow%3ATest) [![Lint Status](https://github.com/hermeznetwork/hermez-node/workflows/Lint/badge.svg)](https://github.com/hermeznetwork/hermez-node/actions?query=workflow%3ALint) [![GoDoc](https://godoc.org/github.com/hermeznetwork/hermez-node?status.svg)](https://godoc.org/github.com/hermeznetwork/hermez-node)

Go implementation of the Hermez node.

## Developing

### Go version

The `hermez-node` has been tested with go version 1.14

### Build

Build the binary and check the current version:

```shell
$ make build
$ bin/node version
```

### Run

First you must edit the default/template config file into [cli/node/cfg.buidler.toml](cli/node/cfg.buidler.toml), 
there are more information about the config file into [cli/node/README.md](cli/node/README.md)

After setting the config, you can build and run the Hermez Node as a synchronizer:

```shell
$ make run-node
```

Or build and run as a coordinator, and also passing the config file from other location:

```shell
$ MODE=sync CONFIG=cli/node/cfg.buidler.toml make run-node
```

To check the useful make commands:

```shell
$ make help
```

### Unit testing

Running the unit tests requires a connection to a PostgreSQL database.  You can
run PostgreSQL with docker easily this way (where `yourpasswordhere` should
be your password):

```shell
$ POSTGRES_PASS="yourpasswordhere" make run-database-container
```

Afterward, run the tests with the password as env var:

```shell
$ POSTGRES_PASS="yourpasswordhere" make test
```

NOTE: `-p 1` forces execution of package test in serial. Otherwise, they may be
executed in parallel, and the test may find unexpected entries in the SQL database
because it's shared among all tests.

There is an extra temporary option that allows you to run the API server using the 
Go tests. It will be removed once the API can be properly initialized with data 
from the synchronizer. To use this, run:

```shell
$ POSTGRES_PASS="yourpasswordhere" make test-api-server
```

### Lint

All Pull Requests need to pass the configured linter.

To run the linter locally, first, install [golangci-lint](https://golangci-lint.run).  
Afterward, you can check the lints with this command:

```shell
$ make gocilint
```

## Usage

### Node

See [cli/node/README.md](cli/node/README.md)

### Proof Server

The node in mode coordinator requires a proof server (a server capable of 
calculating proofs from the zkInputs). There is a mock proof server CLI 
at `test/proofserver/cli` for testing purposes.

Usage of `test/proofserver/cli`:

```shell
USAGE:
    go run ./test/proofserver/cli OPTIONS

OPTIONS:
  -a string
        listen address (default "localhost:3000")
  -d duration
        proving time duration (default 2s)
```

Also, the Makefile commands can be used to run and stop the proof server 
in the background:

```shell
$ make run-proof-mock
$ make stop-proof-mock
```

### `/tmp` as tmpfs

For every processed batch, the node builds a temporary exit tree in a key-value
DB stored in `/tmp`.  It is highly recommended that `/tmp` is mounted as a RAM
file system in production to avoid unnecessary reads a writes to disk.  This
can be done by mounting `/tmp` as tmpfs; for example, by having this line in
`/etc/fstab`:
```
tmpfs			/tmp		tmpfs		defaults,noatime,mode=1777	0 0
```