MongoDB Query Exporter

Prometheus exporter for MongoDB queries. Extract metrics from mongoDB queries results.

Build and Run

Bash

make build
./bin/mongodb_exporter configuration.yaml

Docker

docker run -v /local/path/to/configuration.yaml:/configuration.yaml -e CONFIG=/configuration.yaml ppussar/mongodb_exporter

Run Demo Application

(Requires docker)

Start mongodb and application container.

make start-demo
curl localhost:9090/prometheus

Stop mongodb and application container.

make stop-demo

Configuration

The exporter is configured via YAML file and can be overridden with environment variables.

HTTP Endpoints

Prometheus

Prometheus scrapes its monitored applications regularly via a provided http endpoint. The configuration below opens a http endpoint on http://localhost:9090/prometheus

Liveliness

Liveliness-Endpoint returns http status code 204 - [No Content] as soon as the exporter is started. An HTTP error status code indicates that the application is in bad condition and should be restarted.
The configuration below opens a http endpoint on http://localhost:9090/live

Health

Health-Endpoint returns http status code 200 as soon as the exporter is ready to serve user request. An HTTP error status code indicates that the application is currently not able to collect db metrics. The configuration below opens a http endpoint on http://localhost:9090/health

http:
  port: 9090
  prometheus: /prometheus
  health: /health
  liveliness: /live

HTTPS is currently not supported.

MongoDB Connection

MongoDB connection-string

mongodb:
  uri: mongodb://localhost:27017

Environment Variable Overrides

Configuration values can be overridden using environment variables:

Environment Variable	Config Field	Description
HTTP_PORT	http.port	HTTP server port
HTTP_PROMETHEUS	http.prometheus	Prometheus endpoint path
HTTP_HEALTH	http.health	Health endpoint path
HTTP_LIVELINESS	http.liveliness	Liveness endpoint path
MONGODB_URI	mongodb.uri	MongoDB connection URI

Example:

HTTP_PORT=8080 MONGODB_URI=mongodb://prod:27017 ./mongodb_exporter config.yaml

Metric Queries

metrics:
  - name: my.metric.name
    help: "Description of the metric"
    db: mydb
    collection: mycollection
    tags:
      myTag: "abc"
      bla: "blub"
    aggregate: '[{"$group": { "_id": "$version", "count": { "$sum": 1 }}}]'
    metricsAttribute: count
    tagAttributes:
      version: "_id"
  - name: another.metric.name
    ...

key	description	example	reference
name	Metric name (must follow Prometheus naming conventions)	my_metric_name	https://prometheus.io/docs/concepts/metric_types/
help	Metric help value on prometheus scrape page	Yet another metric
db	MongoDB DB instance, which should be used.	myDB
collection	MongoDB collection, which becomes queried.	myCollection
tags	Map of static tags. Will be added to all resulting metrics.	tagKey: tagValue
aggregate	MongoDB aggregation query (JSON array as string).	'[{"$group": { "_id": "$version", "count": { "$sum": 1 }}}]'	https://docs.mongodb.com/manual/reference/method/db.collection.aggregate/
find	MongoDB find query (JSON object as string).	'{}'	https://docs.mongodb.com/manual/reference/method/db.collection.find/
metricsAttribute	Attribute of the query result, which will be taken as gauge value.	count
tagAttributes	Map of attributes of the query result, which will be taken as additional tags.	tagKey: resultFieldName

Note: Either find or aggregate must be specified, but not both.

Internal Metrics

The exporter provides internal metrics about its own operation:

• mongodb_exporter_query_duration_seconds - Duration of MongoDB queries
• mongodb_exporter_query_errors_total - Total number of query errors by type
• mongodb_exporter_active_queries - Number of currently active queries
• mongodb_exporter_connection_status - MongoDB connection status (1=connected, 0=disconnected)
• mongodb_exporter_metrics_collected_total - Total number of metrics successfully collected

Example Configuration

Given Collection 'fruits'

[
  { "_id": "apples", "qty": 5, "deliverer" : "Fruit Express"},
  { "_id": "bananas", "qty": 7, "deliverer" : "Bananas Daily" },
  { "_id": "oranges", "qty": 12, "deliverer" : "Fruit Express"},
  { "_id": "avocados", "qty": 14, "deliverer" : "Fruit Marked" }
]

Configuration with adapted prometheus endpoint port

version: 1.0
http:
  port: 9090
  prometheus: /prometheus
mongodb:
  uri: mongodb://localhost:27017
metrics:
  - name: fruitstore_stock
    help: "Shows the current stock"
    db: fruitstore
    collection: fruits
    tags:
      provider: mongodb_exporter
    find: "{}"
    metricsAttribute: qty
    tagAttributes:
      type: _id
  - name: fruitstore_total
    db: fruitstore
    collection: fruits
    tags:
      provider: mongodb_exporter
    aggregate: '[{"$group": { "_id": "$deliverer", "pieces": {"$sum": "$qty"}}}]'
    metricsAttribute: pieces
    tagAttributes:
      type: _id

scrape

curl http://localhost:9090/prometheus

Output

# HELP Shows the current stock
# TYPE fruitstore_stock gauge
fruitstore_stock{provider="mongodb_exporter",type="avocados",} 14.0
fruitstore_stock{provider="mongodb_exporter",type="oranges",} 12.0
fruitstore_stock{provider="mongodb_exporter",type="apples",} 5.0
fruitstore_stock{provider="mongodb_exporter",type="bananas",} 7.0
# HELP fruitstore_total
# TYPE fruitstore_total gauge
fruitstore_total{provider="mongodb_exporter",type="Fruit Express",} 17.0
fruitstore_total{provider="mongodb_exporter",type="Bananas Daily",} 7.0
fruitstore_total{provider="mongodb_exporter",type="Fruit Marked",} 14.0