local k = import 'ksonnet/ksonnet.beta.4/k.libsonnet';
local utils = import 'utils.libsonnet';

{
  _config+:: {
    namespace: 'monitoring',
    replicas: 1,

    versions+:: {
      elasticExporter: '1.0.2',
    },

    imageRepos+:: {
      elasticExporter: 'justwatch/elasticsearch_exporter',
    },

    prometheus+:: {
      namespaces+:: ['logging'],
    },

    // Add custom dashboards
    grafanaDashboards+:: {
      'elasticsearch-dashboard.json': (import 'grafana-dashboards/elasticsearch-dashboard.json'),
      'fluentd-dashboard.json': (import 'grafana-dashboards/fluentd-dashboard.json'),
    },
  },

  elasticExporter+:: {
    deployment:
      local deployment = k.apps.v1.deployment;
      local container = k.apps.v1.deployment.mixin.spec.template.spec.containersType;
      local containerPort = container.portsType;

      local podLabels = { 'k8s-app': 'elasticsearch-exporter' };
      local elasticExporter =
        container.new('elasticsearch-exporter',
                      $._config.imageRepos.elasticExporter + ':' + $._config.versions.elasticExporter) +
        container.withCommand([
          '/bin/elasticsearch_exporter',
          '-es.uri=http://elasticsearch.logging.svc:9200',
          '-es.timeout=60s',
          '-es.all=true',
        ]) +
        container.withPorts(containerPort.newNamed(9108, 'es-metrics')) +
        container.mixin.securityContext.capabilities.withDrop(['SETPCAP', 'MKNOD', 'AUDIT_WRITE', 'CHOWN', 'NET_RAW', 'DAC_OVERRIDE', 'FOWNER', 'FSETID', 'KILL', 'SETGID', 'SETUID', 'NET_BIND_SERVICE', 'SYS_CHROOT', 'SETFCAP']) +
        container.mixin.securityContext.withRunAsNonRoot(true) +
        container.mixin.securityContext.withRunAsUser(1000) +
        // container.mixin.securityContext.withReadOnlyRootFilesystem(true) +
        container.mixin.resources.withRequests({ memory: '64Mi', cpu: '25m' }) +
        container.mixin.resources.withLimits({ memory: '128Mi', cpu: '100m' }) +
        container.mixin.livenessProbe.httpGet.withPath('/health') +
        container.mixin.livenessProbe.httpGet.withPort(9108) +
        container.mixin.livenessProbe.withInitialDelaySeconds(30) +
        container.mixin.livenessProbe.withTimeoutSeconds(10) +

        container.mixin.readinessProbe.httpGet.withPath('/health') +
        container.mixin.readinessProbe.httpGet.withPort(9108) +
        container.mixin.readinessProbe.withInitialDelaySeconds(30) +
        container.mixin.readinessProbe.withTimeoutSeconds(10);

      local c = [elasticExporter];

      deployment.new('elasticsearch-exporter', $._config.replicas, c, podLabels) +
      deployment.mixin.metadata.withNamespace($._config.namespace) +
      deployment.mixin.metadata.withLabels(podLabels) +
      deployment.mixin.spec.selector.withMatchLabels(podLabels) +
      deployment.mixin.spec.strategy.withType('RollingUpdate') +
      deployment.mixin.spec.strategy.rollingUpdate.withMaxSurge(1) +
      deployment.mixin.spec.strategy.rollingUpdate.withMaxUnavailable(0) +
      deployment.mixin.spec.template.spec.withRestartPolicy('Always'),

    service:
      local service = k.core.v1.service;
      local servicePort = k.core.v1.service.mixin.spec.portsType;
      local elasticExporterPorts = servicePort.newNamed('es-metrics', 9108, 'es-metrics');

      service.new('elasticsearch-exporter', $.elasticExporter.deployment.spec.selector.matchLabels, elasticExporterPorts) +
      service.mixin.metadata.withNamespace($._config.namespace) +
      service.mixin.metadata.withLabels({ 'k8s-app': 'elasticsearch-exporter' }),

    serviceMonitorElastic:
      utils.newServiceMonitor(
        'elasticsearch',
        $._config.namespace,
        {'k8s-app': 'elasticsearch-exporter'},
        'monitoring',
        'es-metrics',
        'http'),

    serviceMonitorFluentd:
      utils.newServiceMonitor(
        'fluentd-es',
        $._config.namespace,
        {'k8s-app': 'fluentd-es'},
        'logging',
        'metrics',
        'http'),
  },
  // Add Prometheus monitoring rules for ElasticSearch
  prometheusRules+:: {
    groups+: [
      {
        name: 'elasticsearch-k8s-rules',
        rules: [
          {
            expr: '100 * (elasticsearch_filesystem_data_size_bytes - elasticsearch_filesystem_data_free_bytes) / elasticsearch_filesystem_data_size_bytes',
            record: 'elasticsearch_filesystem_data_used_percent',
          },
          {
            expr: '100 - elasticsearch_filesystem_data_used_percent',
            record: 'elasticsearch_filesystem_data_free_percent',
          },

          {
            expr: 'elasticsearch_cluster_health_number_of_nodes < 3',
            alert: 'ElasticsearchTooFewNodesRunning',
            'for': '5m',
            annotations: {
              message: 'There are only {{$value}} < 3 ElasticSearch nodes running',
              summary: 'ElasticSearch running on less than 3 nodes',
            },
            labels: {
              severity: 'critical',
            },
          },
          {
            expr: 'elasticsearch_jvm_memory_used_bytes{area="heap"} / elasticsearch_jvm_memory_max_bytes{area="heap"} > 0.9',
            alert: 'ElasticsearchHeapTooHigh',
            'for': '15m',
            annotations: {
              message: 'The heap usage is over 90% for 15m',
              summary: 'ElasticSearch node {{$labels.node}} heap usage is high',
            },
            labels: {
              severity: 'critical',
            },
          },
        ],
      },
    ],
  },
}