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

### Unit testing

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

```
POSTGRES_PASS=yourpasswordhere; sudo docker run --rm --name hermez-db-test -p 5432:5432 -e POSTGRES_DB=hermez -e POSTGRES_USER=hermez -e POSTGRES_PASSWORD="$POSTGRES_PASS" -d postgres
```

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

```
POSTGRES_PASS=yourpasswordhere go test -p 1 ./...
```

NOTE: `-p 1` forces execution of package test in serial.  Otherwise they may be
executed in paralel and the test may find unexpected entries in the SQL databse
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. This will be removed once the API can be properly initialized,
with data from the synchronizer and so on. To use this, run:

```
FAKE_SERVER=yes POSTGRES_PASS=yourpasswordhere go test -timeout 0  ./api -p 1 -count 1 -v`
```

### Lint

All Pull Requests need to pass the configured linter.

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

```
golangci-lint run --timeout=5m -E whitespace -E gosec -E gci -E misspell -E gomnd -E gofmt -E goimports -E golint --exclude-use-default=false --max-same-issues 0
```

## Usage

### Node

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

### Proof Server

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

Usage of `test/proofserver/cli`:

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

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

### `/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 unecessary reads an 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
```