Document deployment with Gitlab

[jadams]

Summary

Document how to deploy Mattermost operator in conjunction with Gitlab (selfhosted) operator

Steps to reproduce

Attempt to deploy Mattermost operator with Gitlab operator in Kubernetes, search documentation only this page has information with both using helm charts

Expected behavior

Documentation explains how to deploy Mattermost with Gitlab operator

Observed behavior (that appears unintentional)

I had to figure it out, wasn't very difficult from having experience using Gitlab and Mattermost with helm charts but new users may have trouble.

Possible fixes

Add documentation

Example follows:

---
apiVersion: v1
kind: Secret
metadata:
  name: mm-postgres-connection
type: Opaque
data:
  DB_CONNECTION_STRING: "postgres://gitlab:<password_from_gitlab-postgresql-password_secret>@gitlab-postgresql:5432/mattermost-db?sslmode=disable&connect_timeout=10"
---
apiVersion: installation.mattermost.com/v1beta1
kind: Mattermost
metadata:
  name: mattermost-gitlab
spec:
  size: 100users
  ingress:
    enabled: true
    host: "mattermost.example.tld"
    tlsSecret: mattermost-tls
    annotations: {}
  version: 9.8.0
  image: mattermost/mattermost-team-edition
  licenseSecret: ""
  database:
    disableReadinessCheck: true
    external:
      secret: mm-postgres-connection
  fileStore:
    external:
      url: gitlab-minio-svc:9000
      bucket: mattermost-data
      secret: gitlab-minio-secret
  imagePullPolicy: IfNotPresent
  mattermostEnv:
    - name: MM_GITLABSETTINGS_ENABLE
      value: "true"
    - name: MM_GITLABSETTINGS_SECRET
      value: "<gitlab_mattermost_oauth_secret>"
    - name: MM_GITLABSETTINGS_ID
      value: "<gitlab_mattermost_oauth_application_id>"
    - name: MM_GITLABSETTINGS_SCOPE
      value: ""
    - name: MM_GITLABSETTINGS_AUTHENDPOINT
      value: "https://gitlab.example.tld/oauth/authorize"
    - name: MM_GITLABSETTINGS_TOKENENDPOINT
      value: "https://gitlab.example.tld/oauth/token"
    - name: MM_GITLABSETTINGS_USERAPIENDPOINT
      value: "https://gitlab.example.tld/api/v4/user"
    - name: MM_FILESETTINGS_AMAZONS3SSL
      value: "false"
  podExtensions:
    initContainers:
      - name: bootstrap-database
        image: "postgres:13"
        imagePullPolicy: IfNotPresent
        env:
          - name: POSTGRES_PASSWORD_GITLAB
            valueFrom:
              secretKeyRef:
                name: gitlab-postgresql-password
                key: postgresql-password
          - name: POSTGRES_USER_GITLAB
            value: gitlab
          - name: POSTGRES_HOST_GITLAB
            value: gitlab-postgresql
          - name: POSTGRES_PORT_GITLAB
            value: "5432"
          - name: POSTGRES_DB_NAME_MATTERMOST
            value: mattermost-db
        command:
          - sh
          - "-c"
          - |
            if PGPASSWORD=$POSTGRES_PASSWORD_GITLAB psql -h $POSTGRES_HOST_GITLAB -p $POSTGRES_PORT_GITLAB -U $POSTGRES_USER_GITLAB -lqt | cut -d \| -f 1 | grep -qw $POSTGRES_DB_NAME_MATTERMOST; then
            echo "database already exist, exiting initContainer"
            exit 0
            else
            echo "Database does not exist. creating...."
            PGPASSWORD=$POSTGRES_PASSWORD_GITLAB createdb -h $POSTGRES_HOST_GITLAB -p $POSTGRES_PORT_GITLAB -U $POSTGRES_USER_GITLAB $POSTGRES_DB_NAME_MATTERMOST
            echo "Done"
            fi
      - name: create-minio-bucket
        image: "minio/mc:latest"
        imagePullPolicy: IfNotPresent
        env:
          - name: MINIO_ENDPOINT
            value: gitlab-minio-svc
          - name: MINIO_PORT
            value: "9000"
          - name: MINIO_ACCESS_KEY
            valueFrom:
              secretKeyRef:
                name: gitlab-minio-secret
                key: accesskey
          - name: MINIO_SECRET_KEY
            valueFrom:
              secretKeyRef:
                name: gitlab-minio-secret
                key: secretkey
          - name: MATTERMOST_BUCKET_NAME
            value: mattermost-data
        command:
          - sh
          - "-c"
          - |
            echo "Connecting to Minio server: http://$MINIO_ENDPOINT:$MINIO_PORT"
            /usr/bin/mc config host add myminio http://$MINIO_ENDPOINT:$MINIO_PORT $MINIO_ACCESS_KEY $MINIO_SECRET_KEY
            /usr/bin/mc ls myminio
            echo $?
            /usr/bin/mc ls myminio/$MATTERMOST_BUCKET_NAME > /dev/null 2>&1
            if [ $? -eq 1 ] ; then
              echo "Creating bucket '$MATTERMOST_BUCKET_NAME'"
              /usr/bin/mc mb myminio/$MATTERMOST_BUCKET_NAME
            else
              echo "Bucket '$MATTERMOST_BUCKET_NAME' already exists."
              exit 0
            fi