Restructure project

We previously didn't really had any structure in our project apart
from creating a new folder for each package in our project root.
Now that we have accumulated some packages, we use the well-known
Golang project layout in order to clearly communicate our intent
with packages. See https://github.com/golang-standards/project-layout

deploy/api.tpl.nomad

@@ -0,0 +1,76 @@
+job "${NOMAD_SLUG}" {
+  datacenters = ["dc1"]
+  namespace = "${NOMAD_NAMESPACE}"
+
+  group "api" {
+    count = 1
+
+    update {
+      // https://learn.hashicorp.com/tutorials/nomad/job-rolling-update
+      max_parallel  = 1
+      min_healthy_time  = "30s"
+      healthy_deadline  = "5m"
+      progress_deadline = "10m"
+      auto_revert   = true
+    }
+
+    // Don't allow rescheduling to fail deployment and pipeline if task fails
+    reschedule {
+      attempts = 0
+      unlimited = false
+    }
+
+    // No restarts to immediately fail the deployment and pipeline on first task fail
+    restart {
+      attempts = 0
+    }
+
+    network {
+      mode = "bridge"
+
+      port "http" {
+        to     = 7200
+      }
+    }
+
+    service {
+      # urlprefix- tag allows Fabio to discover this service and proxy traffic correctly
+      tags = ["urlprefix-${HOSTNAME}:80/"]
+      name = "${NOMAD_SLUG}"
+      port = "http"
+
+      // Health check to let Consul know we are alive
+      check {
+        name = "health-check"
+        type = "http"
+        port = "http"
+        path = "/api/v1/health"
+        interval = "10s"
+        timeout  = "2s"
+        check_restart {
+          limit = 3  // auto-restart task when health check fails 3x in a row
+        }
+
+      }
+    }
+
+    task "api" {
+      driver = "docker"
+
+      config {
+        image = "${IMAGE_NAME_ENV}"
+      }
+
+      env {
+        POSEIDON_SERVER_ADDRESS = "${POSEIDON_LISTEN_ADDRESS}"
+        POSEIDON_NOMAD_ADDRESS =  "${NOMAD_SERVER_HOST}"
+        POSEIDON_NOMAD_NAMESPACE = "${NOMAD_NAMESPACE}"
+      }
+
+      resources {
+        memory = "100" // 100 MB RAM
+        cpu    = "100" // 100 MHz
+      }
+    }
+  }
+}

deploy/demo-job.tpl.nomad

@@ -0,0 +1,77 @@
+// This job is used by the e2e tests as a demo job.
+
+job "template-0" {
+  datacenters = ["dc1"]
+  type = "batch"
+  namespace = "${NOMAD_NAMESPACE}"
+
+  group "default-group" {
+    ephemeral_disk {
+      migrate = false
+      size    = 10
+      sticky  = false
+    }
+    count = 1
+    scaling {
+      enabled = true
+      max = 300
+    }
+    spread {
+      // see https://www.nomadproject.io/docs/job-specification/spread#even-spread-across-data-center
+      // This spreads the load evenly amongst our nodes
+      attribute = "${node.unique.name}"
+      weight = 100
+    }
+
+    task "default-task" {
+      driver = "docker"
+      kill_timeout = "0s"
+      kill_signal = "SIGKILL"
+
+      config {
+        image = "openhpi/co_execenv_python:3.8"
+        command = "sleep"
+        args = ["infinity"]
+      }
+
+      logs {
+        max_files     = 1
+        max_file_size = 1
+      }
+
+      resources {
+        cpu    = 40
+        memory = 40
+      }
+
+      restart {
+        delay = "0s"
+      }
+    }
+  }
+  group "config" {
+      // We want to store whether a task is in use in order to recover from a downtime.
+      // Without a separate config task, marking a task as used would result in a restart of that task,
+      // as the meta information is passed to the container as environment variables.
+      count = 0
+      task "config" {
+        driver = "exec"
+        config {
+          command = "true"
+        }
+        logs {
+          max_files     = 1
+          max_file_size = 1
+        }
+        resources {
+          // minimum values
+          cpu    = 1
+          memory = 10
+        }
+      }
+      meta {
+        used = "false"
+        prewarmingPoolSize = "0"
+      }
+    }
+}

deploy/docker-make/Dockerfile

@@ -0,0 +1,3 @@
+FROM docker:latest
+
+RUN apk update && apk add make

deploy/nomad-ci/Dockerfile

@@ -0,0 +1,37 @@
+# Simple image containing the Nomad binary to deploy Nomad jobs
+
+FROM golang:latest
+
+# Install prerequisites, gettext contains envsubst used in the CI
+RUN apt-get update && \
+    apt install -y \
+        unzip \
+        wget \
+        gettext \
+        apt-transport-https \
+        ca-certificates \
+        curl \
+        gnupg \
+        lsb-release && \
+    apt-get clean && \
+    rm -rf /var/lib/apt/lists
+
+RUN curl -fsSL https://download.docker.com/linux/debian/gpg | gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg
+RUN echo \
+      "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/debian \
+      $(lsb_release -cs) stable" | tee /etc/apt/sources.list.d/docker.list > /dev/null
+RUN apt-get update && \
+    apt-get install -y docker-ce docker-ce-cli containerd.io && \
+    rm -rf /var/lib/apt/lists
+
+# Download Nomad
+RUN wget "https://releases.hashicorp.com/nomad/1.1.1/nomad_1.1.1_linux_amd64.zip" && \
+    wget "https://releases.hashicorp.com/nomad/1.1.1/nomad_1.1.1_SHA256SUMS" && \
+    grep "nomad_1.1.1_linux_amd64.zip" nomad_1.1.1_SHA256SUMS | sha256sum -c - && \
+    unzip nomad_1.1.1_linux_amd64.zip
+
+# Install Nomad
+RUN mv nomad /usr/sbin/ && nomad -version
+
+COPY nomad-run-and-wait /usr/sbin/
+RUN chmod +x /usr/sbin/nomad-run-and-wait

deploy/nomad-ci/nomad-run-and-wait

@@ -0,0 +1,48 @@
+#!/bin/bash
+
+# Script that runs a Nomad job and watches the deployment status until it finished running
+# See https://github.com/hashicorp/nomad/issues/6818
+
+if [[ $# -eq 0 ]]; then
+  echo "Usage: $0 <path/to/job.nomad>"
+  exit 1
+fi
+
+output=$(nomad run $1 2>&1)
+
+if [[ $? -ne 0 ]]; then
+  echo $output
+  exit 1
+fi
+
+deployment=$(grep -oP "(?<=Evaluation within deployment: \").*(?=\")" <<<$output)
+
+echo "Monitoring deployment $deployment"
+
+timeout=300
+sleepDuration=4
+iterations=$((timeout / sleepDuration))
+
+for i in $(seq $iterations); do
+  if [[ $i -eq $iterations ]]; then
+    # timeout reached, fail deployment and exit
+    nomad deployment fail $deployment
+    exit 1
+  fi
+  output=$(nomad deployment status $deployment 2>&1)
+  grep -E "Status" <<<$output
+  running=$(grep -E "Status.*=.*running" <<<$output)
+  if [[ -z "$running" ]]; then
+    break
+  fi
+  sleep $sleepDuration
+done
+
+echo "#######"
+echo "$output"
+failed=$(grep -E "Status.*=.*failed" <<<$output)
+if [[ -n "$failed" ]]; then
+  exit 1
+fi
+
+exit 0

deploy/nomad-run-env-job.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+
+# This script substitutes environment variables in the given Nomad job and runs it afterwards.
+
+if [[ "$#" -ne 2 ]]; then
+  echo "Usage: $0 path/to/infile path/to/outfile"
+fi
+
+envsubst "$(env | sed -e 's/=.*//' -e 's/^/\$/g')" < $1 > $2
+nomad validate $2
+# nomad plan returns 1 if allocations are created or destroyed which is what we want here
+# https://www.nomadproject.io/docs/commands/job/plan#usage
+nomad plan     $2 || [ $? == 1 ]
+nomad run      $2

deploy/poseidon/Dockerfile

@@ -0,0 +1,8 @@
+FROM alpine:latest
+
+RUN adduser --disabled-password api
+USER api
+COPY poseidon /home/api/
+
+EXPOSE 7200
+CMD ["/home/api/poseidon"]