Create workflow for pushing mayastor images to dockerhub (CAS-450)

This commit does a couple of things:
* ci/cd tests are run only for pull requests and develop (see below)
* schedules nightly builds of develop every day at 2am
* nightly job on develop pushes images to dockerhub
* a commit to master/release branch pushes images to dockerhub
* new script for building & pushing imgs usable even w/o jenkins

Jenkinsfile

@@ -1,16 +1,39 @@
 pipeline {
   agent none
+  triggers {
+    cron('0 2 * * *')
+  }
 
   stages {
     stage('linter') {
       agent { label 'nixos-mayastor' }
+      when {
+        beforeAgent true
+        anyOf {
+          branch 'PR-*'
+          allOf {
+            branch 'develop'
+            triggeredBy 'TimerTrigger'
+          }
+        }
+      }
       steps {
         sh 'nix-shell --run "cargo fmt --all -- --check"'
         sh 'nix-shell --run "cargo clippy --all-targets -- -D warnings"'
         sh 'nix-shell --run "./scripts/js-check.sh"'
       }
     }
     stage('test') {
+      when {
+        beforeAgent true
+        anyOf {
+          branch 'PR-*'
+          allOf {
+            branch 'develop'
+            triggeredBy 'TimerTrigger'
+          }
+        }
+      }
       parallel {
         stage('rust unit tests') {
           agent { label 'nixos-mayastor' }
@@ -49,14 +72,41 @@ pipeline {
             }
           }
         }
+        stage('dev images') {
+          agent { label 'nixos-mayastor' }
+          steps {
+            sh 'nix-build --no-out-link -A images.mayastor-dev-image'
+            sh 'nix-build --no-out-link -A images.mayastor-csi-dev-image'
+            sh 'nix-build --no-out-link -A images.moac-image'
+            sh 'nix-store --delete /nix/store/*docker-image*'
+          }
+        }
       }
     }
-    stage('images') {
+    stage('push images') {
       agent { label 'nixos-mayastor' }
+      when {
+        beforeAgent true
+        anyOf {
+          branch 'master'
+          branch 'release/*'
+          allOf {
+            branch 'develop'
+            triggeredBy 'TimerTrigger'
+          }
+        }
+      }
       steps {
-        sh 'nix-build --no-out-link -A images.mayastor-dev-image'
-        sh 'nix-build --no-out-link -A images.mayastor-csi-dev-image'
-        sh 'nix-build --no-out-link -A images.moac-image'
+        withCredentials([usernamePassword(credentialsId: 'dockerhub', usernameVariable: 'USERNAME', passwordVariable: 'PASSWORD')]) {
+          sh 'echo $PASSWORD | docker login -u $USERNAME --password-stdin'
+        }
+        sh './scripts/release.sh'
+      }
+      post {
+        always {
+          sh 'docker logout'
+          sh 'docker image prune --all --force'
+        }
       }
     }
   }

doc/jenkins.md

@@ -70,7 +70,7 @@ for system configuration of nodes (as opposed to using ansible, salt, etc.).
    };
 
    environment.systemPackages = with pkgs; [
-     wget vim git
+     wget curl vim git
    ];
    }
    ```
@@ -144,6 +144,8 @@ for system configuration of nodes (as opposed to using ansible, salt, etc.).
    boot.kernelModules = [ "nbd" "xfs" "nvme_tcp" "kvm_intel" ];
    boot.extraModprobeConfig = "options kvm_intel nested=1";
 
+   virtualisation.docker.enable = true;
+
    networking.firewall.enable = false;
    networking.hostName = "ci-slave";
 
@@ -164,16 +166,16 @@ for system configuration of nodes (as opposed to using ansible, salt, etc.).
    # account is also possible.
    users.users.mayastor = {
      isNormalUser = true;
-     extraGroups = [ "wheel" ]; # Enable ‘sudo’ for the user.
+     extraGroups = [ "wheel" "docker" ]; # Enable ‘sudo’ for the user.
      password = "";
      openssh.authorizedKeys.keys = [ "ssh-rsa your-key ..." ];
    };
 
-   users.users.jenkins.extraGroups = [ "wheel" ];
+   users.users.jenkins.extraGroups = [ "wheel" "docker" ];
    users.users.jenkins.openssh.authorizedKeys.keys = [ "ssh-rsa key used by Jenkins master ..." ];
 
    environment.systemPackages = with pkgs; [
-     wget vim git jdk openiscsi nvme-cli
+     wget curl vim git jdk openiscsi nvme-cli
    ];
    }
    ```

scripts/release.sh

@@ -0,0 +1,88 @@
+#!/usr/bin/env bash
+
+# Build and upload mayastor docker images to dockerhub repository.
+# Use --dry-run to just see what would happen.
+# The script assumes that a user is logged on to dockerhub.
+
+set -euo pipefail
+
+docker_tag_exists() {
+  curl --silent -f -lSL https://index.docker.io/v1/repositories/$1/tags/$2 1>/dev/null 2>&1
+}
+
+get_tag() {
+  vers=`git tag --points-at HEAD`
+  if [ -z "$vers" ]; then
+    vers=`git rev-parse --short HEAD`
+  fi
+  echo -n $vers
+}
+
+DOCKER="docker"
+NIX_BUILD="nix-build"
+RM="rm"
+SCRIPTDIR=$(dirname "$0")
+IMAGES="mayastor mayastor-csi moac"
+TAG=`get_tag`
+BRANCH=`git rev-parse --abbrev-ref HEAD`
+UPLOAD=
+
+# Check if all needed tools are installed
+curl --version >/dev/null
+if [ $? -ne 0 ]; then
+  echo "Missing curl - install it and put it to your PATH"
+  exit 1
+fi
+$DOCKER --version >/dev/null
+if [ $? -ne 0 ]; then
+  echo "Missing docker - install it and put it to your PATH"
+  exit 1
+fi
+if [ "$#" -gt 0 ]; then
+  if [ "$1" == "--dry-run" ]; then
+    DOCKER="echo $DOCKER"
+    NIX_BUILD="echo $NIX_BUILD"
+    RM="echo $RM"
+  else
+    echo "Usage: release.sh [--dry-run]"
+  fi
+fi
+
+cd $SCRIPTDIR/..
+
+# Build all images first
+for name in $IMAGES; do
+  archive=${name}-image
+  image=mayadata/$name
+  if docker_tag_exists $image $TAG; then
+    echo "Skipping $image:$TAG that already exists"
+  else
+    echo "Building $image:$TAG ..."
+    $NIX_BUILD --out-link $archive --no-build-output -A images.$archive
+    $DOCKER load -i $archive
+    $RM $archive
+    UPLOAD="$UPLOAD $image"
+  fi
+done
+
+# Nothing to upload?
+[ -z "$UPLOAD" ] && exit 0
+
+# Upload them
+for img in $UPLOAD; do
+  echo "Uploading $img:$TAG to registry ..."
+  $DOCKER push $img:$TAG
+done
+
+# Create aliases
+if [ "$BRANCH" == "develop" ]; then
+  for img in $UPLOAD; do
+    $DOCKER tag $img:$TAG $img:develop
+    $DOCKER push $img:develop
+  done
+elif [ "$BRANCH" == "master" ]; then
+  for img in $UPLOAD; do
+    $DOCKER tag $img:$TAG $img:latest
+    $DOCKER push $img:latest
+  done
+fi