Source Code

The source code is openly available. It is programmed in Go 1.11+.

Dependencies

DGraph 1.1+ is a performant, developer-friendly graph database.

Repository

https://github.com/thehonestscoop/lemma-chain

Docker

A Docker image can be created using the Dockerfile.

It is designed to store DGraph data in an s3-compatible bucket.

You can run it with a command like this:

docker run --name lemma-chain -e AWS_ACCESS_KEY_ID=xxx_key -e AWS_SECRET_ACCESS_KEY=xxx_secret -e BUCKET_NAME=xxx_bucket_name --privileged -p 1323:1323 thehonestscoop/lemma-chain

Configuration

All configuration values are set via Environment Variables.

HASHID_SALT

A random string used to create unique identifiers. Once set in production, it must not be modified.

MAX_PAYLOAD_KB (default: 12)

Each reference can store associated custom JSON data. This parameter sets the maximum size of the payload in kilobytes.

BEHIND_PROXY (default: 0)

If the application sits behind a proxy, set to 1.

PORT (default: 1323)

The port used to listen for connections.

QUERY_TIMEOUT (default: 300ms)

To prevent abuse of the service, a timeout (in ms) can be set.

CACHE_DURATION (default: 15)

Results of GET endpoints are cached for a duration (in minutes) based on this setting.

RATE_LIMIT (default 4.0)

To prevent abuse of the service, a maximum number of requests per second per IP address can be set.

RECAPTCHA_SECRET

All POST requests require passing Google recaptcha validation. You can set your recaptcha secret here. The default value allows all requests to pass validation.

ACCOUNT VERIFICATION

If both GMAIL_ACCOUNT and GMAIL_PASSWORD are not set, all accounts will be created in a verified state.

WEBSITE_URL

The website url (if you create references and accounts via a website).

HOST_URL

The url of the lemma chain server application.

GMAIL_ACCOUNT

Gmail email address for account verification emails to be sent from.

GMAIL_PASSWORD

Gmail password for the above gmail account.

SMTP_HOST (default: “smtp.gmail.com”)

SMTP Host domain of your email server.

SMTP_PORT (default: 587)

SMTP Port of your email server.