TrueStreet

A read/write storage endpoint to allow Prometheus to use Google Cloud Spanner as a timeseries data store. Truestreet leverages Google Cloud Spanner database to store timeseries data, resulting in a fast and scalable monitoring system.

Building

Truestreet has migrated from go-dep to go modules to manage versioning and its dependencies.

To build a truestreet binary from source, first checkout the source code and then issue go build command inside the truestreet directory.

git clone https://github.com/google/truestreet.git

cd truestreet

go build

go test

A minimal docker image is produced by following command.

docker build -t truestreet .

Google Cloud Spanner setup

If you have not already, set up the Google Cloud SDK to use the command line interface. Make sure to configure the CLI to be on the correct GCP project.

Create an instance with the command

gcloud spanner instances create truestreet --config=regional-us-central1 --description="TrueStreet Instance" --nodes=1

Any of the arguments can be changed to your needs, just make sure to reflect the name of the instance in TrueStreet's command line arguments. Additionally, it is recommended to consider how heavy the load will be on Spanner, Kubernetes can provide automatic scaling of TrueStreet pods, but setting up the appropriate number of Spanner nodes is not determined by TrueStreet.

TrueStreet command line arguments

port       Port for serving TrueStreet (Default 1760)
project    Name of GCP project
instance   Name of Cloud Spanner instance
db         Name of database inside Cloud Spanner instance
new        Create new database if one does not already exist (Default true)
workers    Number of concurrent routines to write samples (Default 10)
help       Prints help text

For example, creating a database called 'truestreet-db' on the Spanner Instance 'truestreet' would require the flags

--project myProject --instance truestreet --db truestreet-db

By default, TrueStreet wil listen on port 1760. Using the provided project, instance and db name, TrueStreet will first attempt to connect to an existing database on the provided instance. If one is not found and the 'new' flag is set to true, it will create a database to run on the instance.

Prometheus Configuration

Add the following lines to your prometheus.yml to configure remote read and write. Additional configuration options are available and can be inspected here Two suggestions are that, for remote writes, the max samples per second can be increased from its default of 100 samples. If samples are being written en masse from Prometheus to TrueStreet, it's more efficient to batch them here as well, as there are fewer separate requests. TrueStreet batches them to Spanner anyway. A second suggestion is that, to see TrueStreet reading at work, Prometheus can be forced to read only from TrueStreet. This is helpful for testing if the connection is working, and also for retrieving data from other Prometheus instances that may also be writing to the same Spanner database.

remote_write:
    - url: http://<adapter-address>:1760/write
      queue_config:
        max_samples_per_send: 250

remote_read:
    - url: http://<adapter-address>:1760/read
      read_recent: true # Optional to test if read is working

TrueStreet also provides Prometheus metrics. These new metrics can be scraped by adding another target for Prometheus.

scrape_configs:
  - job_name: truestreet
    static_configs:
      - targets: ['localhost:1760']