This module periodically fetches monitoring metrics from Google Cloud Platform using
https://cloud.google.com/monitoring/api/metrics_gcp[Stackdriver Monitoring API] for Google Cloud Platform services.

IMPORTANT: Extra GCP charges on Stackdriver Monitoring API requests may be
generated by this module. Please see <<gcp-api-requests,rough estimation of the number of API calls>>
for more details.

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== Module config and parameters
This is a list of the possible module parameters you can tune:

* *zone*: A single string with the zone you want to monitor like `us-central1-a`.
Or you can specific a partial zone name like `us-central1-` or `us-central1-*`,
which will monitor all zones start with `us-central1-`: `us-central1-a`,
`us-central1-b`, `us-central1-c` and `us-central1-f`.
Please see https://cloud.google.com/compute/docs/regions-zones#available[GCP zones]
for zones that are available in GCP.

* *region*: A single string with the region you want to monitor like `us-central1`.
This will enable monitoring for all zones under this region. Or you can specific
a partial region name like `us-east` or `us-east*`, which will monitor all regions start with
`us-east`: `us-east1` and `us-east4`. If both region and zone are configured,
only region will be used.
Please see https://cloud.google.com/compute/docs/regions-zones#available[GCP regions]
for regions that are available in GCP. If both `region` and `zone` are not
specified, metrics will be collected from all regions/zones.

* *project_id*: A single string with your GCP Project ID

* *credentials_file_path*: A single string pointing to the JSON file path
reachable by Metricbeat that you have created using IAM.

* *exclude_labels*: (`true`/`false` default `false`) Do not extract extra labels
and metadata information from metricsets and fetch metrics only. At the moment,
*labels and metadata extraction is only supported* in `compute` metricset.

* *period*: A single time duration specified for this module collection frequency.

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== Example configuration
* `compute` metricset is enabled to collect metrics from `us-central1-a` zone
in `elastic-observability` project.
+
[source,yaml]
----
- module: googlecloud
  metricsets:
    - compute
  zone: "us-central1-a"
  project_id: "elastic-observability"
  credentials_file_path: "your JSON credentials file path"
  exclude_labels: false
  period: 60s
----

* `compute` and `pubsub` metricsets are enabled to collect metrics from all zones
under `us-central1` region in `elastic-observability` project.
+
[source,yaml]
----
- module: googlecloud
  metricsets:
    - compute
    - pubsub
  region: "us-central1"
  project_id: "elastic-observability"
  credentials_file_path: "your JSON credentials file path"
  exclude_labels: false
  period: 60s
----

* `compute` metricset is enabled to collect metrics from all regions starts with
`us-west` in `elastic-observability` project, which includes all zones under
`us-west1`, `us-west2`, `us-west3` and `us-west4`.
+
[source,yaml]
----
- module: googlecloud
  metricsets:
    - compute
    - pubsub
  region: "us-west"
  project_id: "elastic-observability"
  credentials_file_path: "your JSON credentials file path"
  exclude_labels: false
  period: 60s
----

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== Authentication, authorization and permissions.
Authentication and authorization in Google Cloud Platform can be achieved in many ways. For the current version of the Google Cloud Platform module for Metricbeat, the only supported method is using Service Account JSON files. A typical JSON with a private key looks like this:

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=== Example Credentials
[source,json]
----
{
  "type": "service_account",
  "project_id": "your-project-id",
  "private_key_id": "a_private_key_id",
  "private_key": "-----BEGIN PRIVATE KEY-----your private key\n-----END PRIVATE KEY-----\n",
  "client_email": "some-email@your-project-id.iam.gserviceaccount.com",
  "client_id": "123456",
  "auth_uri": "https://accounts.google.com/o/oauth2/auth",
  "token_uri": "https://oauth2.googleapis.com/token",
  "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
  "client_x509_cert_url": "https://www.googleapis.com/robot/v1/metadata/x509/metricbeat-testing%40your-project-id.iam.gserviceaccount.com"
}
----

Generally, you have to create a Service Account and assign it the following roles or the permissions described on each role (applies to all metricsets):

* `Compute Viewer` (1 permission in use of 138):
- `monitoring.metricDescriptors.list`
- `monitoring.timeSeries.list`

* `Monitoring Viewer` (2 permissions in use of 13)
- `compute.instances.get`

You can play in IAM pretty much with your service accounts and Instance level access to your resources (for example, allowing that everything running in an Instance is authorized to use the Compute API). The module uses Google Cloud Platform libraries for authentication so many possibilities are open but the Module is only supported by using the method mentioned above.

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== Google Cloud Platform module: Under the hood

Google Cloud Platform offers the https://cloud.google.com/monitoring/api/metrics_gcp[Stackdriver Monitoring API] to fetch metrics from its services. *Those metrics are retrieved one by one*.

If you also want to *extract service labels* (by setting `exclude_labels` to false, which is the default state). You also make a new API check on the corresponding service. Service labels requires a new API call to extract those metrics. In the worst case the number of API calls will be doubled. In the best case, all metrics come from the same GCP entity and 100% of the required information is included in the first API call (which is cached for subsequent calls).

If `period` value is set to 5-minute and sample period of the metric type is 60-second, then this module will collect data from this metric type once every 5 minutes with aggregation.
GCP monitoring data has a up to 240 seconds latency, which means latest monitoring data will be up to 4 minutes old. Please see https://cloud.google.com/monitoring/api/v3/latency-n-retention[Latency of GCP Monitoring Metric Data] for more details.
In googlecloud module, metrics are collected based on this ingest delay, which is also obtained from ListMetricDescriptors API.

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[[gcp-api-requests]]
=== Rough estimation of the number of API calls
Google Cloud Platform pricing depends of the number of requests you do to their API's. Here you have some information that you can use to make an estimation of the pricing you should expect. For example, imagine that you have a Compute Metricset activated and you don't want to exclude labels. You have a total of 20 instances running in a particular GCP project, region and zone.

For example, if Compute Metricset fetches 14 metrics (which is the number of metrics fetched in the early beta version). Each of those metrics will attempt an API call to Compute API to retrieve also their metadata. Because you have 20 different instances, the total number of API calls that will be done on each refresh period are: 14 metrics + 20 instances = 34 API requests every 5 minutes if that is your current Period. 9792 API requests per day with one zone. If you add 2 zones more with the same amount of instances you'll have 19584 API requests per day (9792 on each zone) or around 587520 per month for the Compute Metricset. This maths must be done for each different Metricset with slight variations.

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== Metricsets
Currently, we have `billing`, `compute`, `loadbalancing`, `pubsub`, `metrics` and
`storage` metricset in `googlecloud` module.

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=== `billing`
This metricset fetches billing metrics from https://cloud.google.com/bigquery[GCP BigQuery]
Cloud Billing allows users to export billing data into BigQuery automatically
throughout the day. This metricset gets access to the daily cost detail table
periodically to export billing metrics for further analysis.

The `billing` metricset comes with a predefined dashboard:

image::./images/metricbeat-googlecloud-billing-overview.png[]

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=== `compute`
This metricset fetches metrics from https://cloud.google.com/compute/[Compute Engine]
Virtual Machines in Google Cloud Platform. The `compute` metricset contains some
of the metrics exported from the https://cloud.google.com/monitoring/api/metrics_gcp#gcp-compute[GCP Compute Monitoring API].
Extra labels and metadata are also extracted using the https://cloud.google.com/compute/docs/reference/rest/v1/instances/get[Compute API].
This is enough to get most of the info associated with a metric like compute
labels and metadata and metric specific Labels.

The `compute` metricset comes with a predefined dashboard:

image::./images/metricbeat-googlecloud-compute-overview.png[]

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=== `loadbalancing`
This metricset fetches metrics from https://cloud.google.com/load-balancing/[Load Balancing]
in Google Cloud Platform. The `loadbalancing` metricset contains all metrics
exported from the https://cloud.google.com/monitoring/api/metrics_gcp#gcp-loadbalancing[GCP Load Balancing Monitoring API].

The `loadbalancing` metricset comes with two predefined dashboards:

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==== HTTPS
For HTTPS load balancing:
image::./images/metricbeat-googlecloud-load-balancing-https-overview.png[]

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==== L3
For L3 load balancing:
image::./images/metricbeat-googlecloud-load-balancing-l3-overview.png[]

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==== TCP/SSL/Proxy
For TCP/SSL/Proxy load balancing:
image::./images/metricbeat-googlecloud-load-balancing-tcp-ssl-proxy-overview.png[]

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=== `pubsub`
This metricset fetches metrics from https://cloud.google.com/pubsub/[Pub/Sub]
topics and subscriptions in Google Cloud Platform. The `pubsub` metricset
contains all GA stage metrics exported from the
https://cloud.google.com/monitoring/api/metrics_gcp#gcp-pubsub[GCP PubSub Monitoring API].

The `pubsub` metricset comes with a predefined dashboard:

image::./images/metricbeat-googlecloud-pubsub-overview.png[]

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=== `metrics`
`metrics` metricset uses Google Cloud Operations/Stackdriver, which provides
visibility into the performance, uptime, and overall health of cloud-powered
applications. It collects metrics, events, and metadata from different services
from Google Cloud.
This metricset is to collect https://cloud.google.com/monitoring/api/metrics_gcp[monitoring metrics]
from Google Cloud using `ListTimeSeries` API.

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=== `storage`
This metricset fetches metrics from https://cloud.google.com/storage/[Storage]
in Google Cloud Platform. The `storage` metricset contains all GA metrics
exported from the https://cloud.google.com/monitoring/api/metrics_gcp#gcp-storage[GCP Storage Monitoring API].

We recommend users to define `period: 5m` for this metricset because in Google
Cloud, storage monitoring metrics are written every 5-minute sample period with
a 10-minute ingest delay.

The `storage` metricset comes with a predefined dashboard:

image::./images/metricbeat-googlecloud-storage-overview.png[]
