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Essix runs an essential simple secure stable scalable stateless server for HTTP resources.
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Essix runs an essential simple secure stable scalable stateless server for HTTP resources.


$ go get -u

The essix command manages Essix apps, their server certificates (TLS/HTTPS), their backend databases (RethinkDB), and their infrastructure (Docker Swarm Mode).

Follow the Quickstart to get your first app running within minutes, on a swarm near you.

With $ essix init, a new Essix app package is inititialised, where you would add your own functionality. It includes the Profile example of how things can be done.



Essix basically provides just what you need for running a reliable web application.


Essix cuts out the cruft, and facilitates building directly on the excellent standards that created the web.

  • The server runs HTTP/2 with TLS (https).
  • $ essix cert generates self-signed TLS certificates, and trusted certficates for domains you own, through LetsEncrypt
  • Templates for HTML documents are defined with Ace, a Go version of Jade. Progressively enhance them with CSS styles, SVG graphics, and/or JavaScript behaviours as you like. Custom templates may override core templates.
  • Every path in <app>/resources/static/... is statically served as https://<host>/static/...
  • Request routes are declared with their method, URL, and handler function, e.g. router.GET("/account/activate", account.ActivateForm)
  • Business objects gain CRUD operations from the Entity base type, which manages their storage in a RethinkDB cluster.
  • Server and user errors are communicated through a customisable error template.
  • The Post/Redirect/Get pattern is a first class citizen.
  • HTML email is sent using the same Ace templates. Failed emails are queued automatically to send later.
  • Multi-language labels and text are managed through the simple definition of messages with keys and accompanying translations. Custom messages may override core messages.


Essix creates computing environments from scratch in a snap, scales transparently from a local laptop to a multi-continent cloud, and only knows how to run in fault tolerant mode.

  • $ essix nodes creates and manages Docker Swarm Mode swarms, either locally or in the cloud. See the blogpost for the ins and outs.
  • $ essix r installs a RethinkDB cluster on a swarm's nodes.
  • $ essix build compiles an Essix app's sources, and builds a Docker image for it.
  • $ essix run creates a service on the swarm that runs any number of replicas of the app's image.
  • $ essix jmeter runs distributed load tests and spins up any number of remote servers to share in the generated load.
  • The app server is stateless (resource data is kept in the database cluster, and user session data is kept client-side in a cookie), meaning each replica is the same as any of the others, every request can be handled by any of the replicas, and if one fails, the others continue to serve.


All communication between client and server is encrypted through TLS (https). User session tokens are stored as a secure cookie

  • HTTP PUT, POST, PATCH, and DELETE requests are protected from CSRF attacks automatically, using encrypted form tokens.
  • On sign up, the user's email address is verified before the new account is activated. User passwords are never stored; on sign in, the given password is verified through an encrypted hash value in the database. The processes for resetting the password, changing the email address, or suspending an account, include an email verification step.
  • Specific request routes can be declaratively shielded from unauthorised access, e.g. router.PUT("/account/email", secure.Handle(account.ChangeEmail))
  • Specific request routes can be declaratively rate limited (obsoleting the need for captchas) e.g. router.PUT("/session", ratelimit.Handle(account.LogIn))
  • A firewall is included for cloud nodes, opening only ports 80, and 443 for the app (80 redirects to 443), 2376, 2377, 7946, and 4789 for Docker Swarm Mode, and 22 for ssh. An ssh tunnel provides access to the RethinkDB admin site.


  1. Verify the Prerequisites.
  2. Install Essix: $ go get -u
  3. Initialise a new Essix app: $ essix init
  4. Create a self-signed TLS certificate: $ cd $GOPATH/src/, then: $ essix cert
  5. Create a local one-node Docker swarm: $ essix nodes -H -m 1 create dev
  6. Install RethinkDB on the swarm: $ essix r create dev
  7. Run your app on the swarm: $ cd $GOPATH/src/, then: $ essix -e build you 0.1 dev
  8. Point your browser to It'll complain about not trusting your self-signed certificate, but you can instruct it to accept it anyway. $ essix cert can generate officially trusted certificates as well.
  9. Configure the server's email account details.
  10. Put your app ($GOPATH/src/ under version control & get creative.

Run $ essix help for some more elaborate usage examples.


  1. Essix apps are built in the Go language.
  2. Do create a Go working directory & set the $GOPATH environment variable to point to it.
  3. The go get command relies on a version control system, e.g. GitHub.
  4. The essix command runs on bash, which should be present on Mac or Linux. For Windows, Git Bash should work.
  5. Deploying apps with the essix command, relies on Docker. Docker Machine & VirtualBox are normally included in the Docker installation.

Essix data is stored in a RethinkDB cluster, which the essix command completely manages within Docker, so not a prerequisite.

After installing Essix with $ go get -u, the essix command relies on the $GOPATH/src/ directory; leave it untouched.

Essix command


essix init PACKAGE
  Initialise a new essix app in the given new directory under $GOPATH.

essix cert DOMAIN [EMAIL]
  Generate a TLS certificate for the given domain.
  Certificate gets saved in ./resources/certificates
  Without EMAIL,
    a self-signed certificate is produced.
  With EMAIL,
    a trusted certificate is produced through LetsEncrypt.
    The current LetsEncrypt approach relies on a DNS configuration on DigitalOcean,
    and requires the DIGITALOCEAN_ACCESS_TOKEN environment variable.

  Create a Docker Swarm Mode swarm, and manage its nodes.
  Run 'essix nodes help' for more information.

  Create a RethinkDB cluster on a swarm, and/or start its web admin.
  Run 'essix r help' for more information.

essix [OPTIONS] build REPO TAG [SWARM]
  Format & compile go sources in the current directory, and build a Docker
  image named REPO/APP:TAG
  APP is the current directory's name, is also the service name.
  Without SWARM,
    the OPTIONS are ignored, and the image is built locally,
    then pushed to the repository. Default repository is Docker Hub.
  With SWARM,
    the image is built remotely on each of the swarm's nodes,
    and the service is run there, with the given OPTIONS.

  Run a service from an image on a swarm.
    -e key=value ...  environment variables
    -r replicas       number of replicas to run (default=1)

essix jmeter run JMX APP_SWARM LOAD_SWARM
  Run Apache JMeter load tests, generating a dashboard report under
  JMX         The path to the JMeter test plan definition .jmx file.
  APP_SWARM   The swarm running the app under test.
              Its nodes' IP addresses are set as environment variables
              NODE_0, NODE_1, ..., NODE_x
  LOAD_SWARM  The swarm that will run the test, distributing the
              generated load across its remote JMeter servers.
  Use `essix jmeter server start LOAD_SWARM` to create the remote servers.
  Use `essix jmeter perfmon start APP_SWARM` to install the PerfMon Server Agent.

essix jmeter server ACTION SWARM
  Provision the swarm's nodes with a remote JMeter "slave" server.
  ACTION  Either start, stop, or restart.

essix jmeter perfmon ACTION SWARM
  Provision the swarm's nodes with the PerfMon Server Agent.
  ACTION  Either start, stop or restart.

essix help
  Display this message.


  $ essix init
      Initialises a base structure for an Essix app in $GOPATH/src/

  $ essix cert
      Generates a self-signed TLS certificate for the given domain.

  $ export DIGITALOCEAN_ACCESS_TOKEN="94dt7972b863497630s73012n10237xr1273trz92t1"
  $ essix cert
      Generates a trusted TLS certificate for the given domain.

  $ essix nodes -m 1 -w 2 -H create dev
      Creates swarm dev on VirtualBox, with one manager node, and 2 worker
      nodes. Adds hostname to /etc/hosts, resolving to the
      manager node's ip address.

  $ export DIGITALOCEAN_ACCESS_TOKEN="94dt7972b863497630s73012n10237xr1273trz92t1"
  $ essix nodes -m 1 -d digitalocean -F create www
      Creates one-node swarm www on DigitalOcean, with a firewall enabled.
  $ export DIGITALOCEAN_REGION="ams3"
  $ essix nodes -w 1 -d digitalocean -F create www
      Adds an Amsterdam based worker node to swarm www.
  $ export DIGITALOCEAN_REGION="sgp1"
  $ essix nodes -w 1 -d digitalocean -F create www
      Adds a Singapore based worker node to swarm www.

  $ essix r create dev
      Creates a RethinkDB cluster on swarm dev, and opens the cluster's
      administrator web page.

  $ essix r dev
      Opens the dev swarm RethinkDB cluster's administrator web page.

  $ essix build essix 0.2
      Locally builds the essix/APP:0.2 image, and pushes it to the repository.
  $ essix run -e -r 6 essix 0.2 www
      Starts 6 replicas of the service on swarm www, using image essix/APP:0.2,
      which is downloaded from the repository, if not found locally.

  $ essix -e build essix 0.3 dev
      Builds image essix/APP:0.3 on swarm dev's nodes, and runs the service
      on dev, with the given DOMAIN environment variable set.

  $ essix nodes -m 3 create load
  $ essix jmeter server start load
      Creates and provisions a swarm of remote JMeter servers.
  $ essix jmeter perfmon start dev
      Installs the PerfMon Server Agent on swarm dev's nodes.
  $ essix jmeter run test_plan.jmx dev load
      Runs a distributed load test on the load swarm, targeting the dev swarm.

App directory and Profile example

The essix init command renders this directory structure:

Essix init directory structure


Entry point for the service to initialise and run the app.


Package defining messages and translations. Add custom messages (like example.go), and/or copy any of the default files to customise translations, or add translations for other languages (pull requests welcome).


Package defining business model data entities. The example defines a Profile entity, showing how to:

  • Define the type, embedding the entity Base type
  • Register the type as a data entity
  • Construct an instance of the type


Directory with resource files for the app, that gets added to the service image, after merging with the default resources.


Let's Encrypt account data, resulting from essix cert


Certificate files resulting from essix cert


Any data files the app needs. The Profile example includes a list of contries, and a list of time zones.


Any static files to serve. The example just relies on the defaults merged in on essix build.


The Ace templates for HTML documents. example contains the example Profile form template, and essix contains a customised version of the default home page content.


Package defining request routes and their handlers. example.go defines the Profile example routes, and the example package contains their handlers (profile.go) and the loading of country and time zone data (data.go)


The vendor directory is the place where the govendor tool keeps track of the app's package dependencies.


Trusted certificates

For how to prepare for generating trusted certificates with essix cert, see the blogpost.

Email configuration

The email function needs email server & account details configured in the database. $ essix r dev brings up the administrator site of the RethinkDB cluster (assuming you target the dev swarm). Navigate to the Data Explorer, and paste this command:

  EmailAddress: '',
  PWD: 'secret',
  PortNumber: '587',
  SmtpServer: ''

RethinkDB Essix email configuration Replace the values with what's appropriate for your account, then click the Run button. Restart the app server to read in the new config:

$ docker-machine ssh dev-manager-1 docker service scale myapp=0
myapp scaled to 0
$ docker-machine ssh dev-manager-1 docker service scale myapp=1
myapp scaled to 1

Note that should you choose to use a Gmail account, you need to turn on 'Allow Less Secure Apps to Access Account' in the account settings

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