This is a permanent fork of Database agnostic SQL exporter for Prometheus created by @free.
SQL Exporter is a configuration driven exporter that exposes metrics gathered from DBMSs, for use by the Prometheus monitoring system. Out of the box, it provides support for the following databases and compatible interfaces:
- MySQL
- PostgreSQL
- Microsoft SQL Server
- Clickhouse
- Snowflake
- Vertica
In fact, any DBMS for which a Go driver is available may be monitored after rebuilding the binary with the DBMS driver included.
The collected metrics and the queries that produce them are entirely configuration defined. SQL queries are grouped into collectors -- logical groups of queries, e.g. query stats or I/O stats, mapped to the metrics they populate. Collectors may be DBMS-specific (e.g. MySQL InnoDB stats) or custom, deployment specific (e.g. pricing data freshness). This means you can quickly and easily set up custom collectors to measure data quality, whatever that might mean in your specific case.
Per the Prometheus philosophy, scrapes are synchronous (metrics are collected on every /metrics
poll) but, in order to
keep load at reasonable levels, minimum collection intervals may optionally be set per collector, producing cached
metrics when queried more frequently than the configured interval.
Get Prometheus SQL Exporter, either as a packaged release, as a Docker image.
Use the -help
flag to get help information.
$ ./sql_exporter -help
Usage of ./sql_exporter:
-config.file string
SQL Exporter configuration file name. (default "sql_exporter.yml")
-web.listen-address string
Address to listen on for web interface and telemetry. (default ":9399")
-web.metrics-path string
Path under which to expose metrics. (default "/metrics")
[...]
Prerequisites:
- Go Compiler
- GNU Make
By default we produce a binary with all the supported drivers with the following command:
make build
It's also possible to reduce the size of the binary by only including specific set of drivers like Postgres, MySQL and
MSSQL. In this case we need to update drivers.go
. To avoid manual manipulation there is a helper code generator
available, so we can run the following commands:
make drivers-minimal
make build
The first command will regenerate drivers.go
file with a minimal set of imported drivers using drivers_gen.go
.
Running make drivers-all
will regenerate driver set back to the current defaults.
Feel free to revisit and add more drivers as required. There's also the custom
list that allows managing a separate
list of drivers for special needs.
If you run SQL Exporter from Windows, it might come in handy to register it as a service to avoid interactive sessions.
It is important to define --config.file
parameter to load the configuration file. The other settings can be added
as well. The registration itself is performed with Powershell or CMD (make sure you run it as Administrator):
Powershell:
New-Service -name "SqlExporterSvc" `
-BinaryPathName "%SQL_EXPORTER_PATH%\sql_exporter.exe --config.file %SQL_EXPORTER_PATH%\sql_exporter.yml" `
-StartupType Automatic `
-DisplayName "Prometheus SQL Exporter"
CMD:
sc.exe create SqlExporterSvc binPath= "%SQL_EXPORTER_PATH%\sql_exporter.exe --config.file %SQL_EXPORTER_PATH%\sql_exporter.yml" start= auto
%SQL_EXPORTER_PATH%
is a path to the SQL Exporter binary executable. This document assumes that configuration files
are in the same location.
SQL Exporter is deployed alongside the DB server it collects metrics from. If both the exporter and the DB
server are on the same host, they will share the same failure domain: they will usually be either both up and running
or both down. When the database is unreachable, /metrics
responds with HTTP code 500 Internal Server Error, causing
Prometheus to record up=0
for that scrape. Only metrics defined by collectors are exported on the /metrics
endpoint.
SQL Exporter process metrics are exported at /sql_exporter_metrics
.
The configuration examples listed here only cover the core elements. For a comprehensive and comprehensively documented
configuration file check out
documentation/sql_exporter.yml
.
You will find ready to use "standard" DBMS-specific collector definitions in the
examples
directory. You may contribute your
own collector definitions and metric additions if you think they could be more widely useful, even if they are merely
different takes on already covered DBMSs.
./sql_exporter.yml
# Global settings and defaults.
global:
# Subtracted from Prometheus' scrape_timeout to give us some headroom and prevent Prometheus from
# timing out first.
scrape_timeout_offset: 500ms
# Minimum interval between collector runs: by default (0s) collectors are executed on every scrape.
min_interval: 0s
# Maximum number of open connections to any one target. Metric queries will run concurrently on
# multiple connections.
max_connections: 3
# Maximum number of idle connections to any one target.
max_idle_connections: 3
# Maximum amount of time a connection may be reused to any one target. Infinite by default.
max_connection_lifetime: 10m
# The target to monitor and the list of collectors to execute on it.
target:
# Target name (optional). Setting this field enables extra metrics e.g. `up` and `scrape_duration` with
# the `target` label that are always returned on a scrape.
name: "prices_db"
# Data source name always has a URI schema that matches the driver name. In some cases (e.g. MySQL)
# the schema gets dropped or replaced to match the driver expected DSN format.
data_source_name: 'sqlserver:https://prom_user:[email protected]:1433'
# Collectors (referenced by name) to execute on the target.
# Glob patterns are supported (see <https://pkg.go.dev/path/filepath#Match> for syntax).
collectors: [pricing_data_freshness, pricing_*]
# In case you need to connect to a backend that only responds to a limited set of commands (e.g. pgbouncer) or
# a data warehouse you don't want to keep online all the time (due to the extra cost), you might want to disable `ping`
# enable_ping: true
# Collector definition files.
# Glob patterns are supported (see <https://pkg.go.dev/path/filepath#Match> for syntax).
collector_files:
- "*.collector.yml"
NOTE: The collectors
and collector_files
configurations support Glob pattern matching.
To match names with literal pattern terms in them, e.g. collector_*1*
, these must be escaped: collector_\*1\*
.
Collectors may be defined inline, in the exporter configuration file, under collectors
, or they may be defined in
separate files and referenced in the exporter configuration by name, making them easy to share and reuse.
The collector definition below generates gauge metrics of the form pricing_update_time{market="US"}
.
./pricing_data_freshness.collector.yml
# This collector will be referenced in the exporter configuration as `pricing_data_freshness`.
collector_name: pricing_data_freshness
# A Prometheus metric with (optional) additional labels, value and labels populated from one query.
metrics:
- metric_name: pricing_update_time
type: gauge
help: 'Time when prices for a market were last updated.'
key_labels:
# Populated from the `market` column of each row.
- Market
static_labels:
# Arbitrary key/value pair
portfolio: income
values: [LastUpdateTime]
# Static metric value (optional). Useful in case we are interested in string data (key_labels) only. It's mutually
# exclusive with `values` field.
# static_value: 1
query: |
SELECT Market, max(UpdateTime) AS LastUpdateTime
FROM MarketPrices
GROUP BY Market
To keep things simple and yet allow fully configurable database connections, SQL Exporter uses DSNs (like
sqlserver:https://prom_user:[email protected]:1433
) to refer to database instances.
Since v0.9.0 sql_exporter
relies on github.com/xo/dburl
package for parsing Data Source Names (DSN).
This can potentially affect your connection to certain databases like MySQL, so you might want to adjust your connection
string accordingly:
mysql:https://user:pass@localhost/dbname - for TCP connection
mysql:/var/run/mysqld/mysqld.sock - for Unix socket connection
If your DSN contains special characters in any part of your connection string (including passwords), you might need to
apply URL encoding (percent-encoding) to them.
For example, p@$$w0rd#abc
then becomes p%40%24%24w0rd%23abc
.
For additional details please refer to xo/dburl documentation.
If the database runs on AWS EC2 instance, this is a secure option to store the DSN without having it in the configuration file. To use this option:
- Create a secret in
key/value pairs format, specify Key
data_source_name
and then for Value enter the DSN value. For the secret name, enter a name for your secret, and pass that name in the configuration file as a value foraws_secret_name
item undertarget
. Secret json example:
{
"data_source_name": "sqlserver:https://prom_user:[email protected]:1433"
}
- Configuration file example:
...
target:
aws_secret_name: '<AWS_SECRET_NAME>'
...
- Allow read-only access from EC2 IAM role to the secret by attaching a resource-based policy to the secret. Policy example:
{
"Version" : "2012-10-17",
"Statement" : [
{
"Effect": "Allow",
"Principal": {"AWS": "arn:aws:iam::123456789012:role/EC2RoleToAccessSecrets"},
"Action": "secretsmanager:GetSecretValue",
"Resource": "*",
}
]
}
Currently, AWS Secret Manager integration is only available for a single target configuration.
It is possible to run a single exporter instance against multiple database connections. In this case we need to
configure jobs
list instead of the target
section as in the following example:
jobs:
- job_name: db_targets
collectors: [pricing_data_freshness, pricing_*]
enable_ping: true # Optional, true by default. Set to `false` in case you connect to pgbouncer or a data warehouse
static_configs:
- targets:
pg1: 'pg:https://[email protected]:25432/postgres?sslmode=disable'
pg2: 'pg:https://[email protected]:25432/testdb?sslmode=disable'
, where DSN strings are assigned to the arbitrary instance names (i.e. pg1 and pg2).
We can also define multiple jobs to run different collectors against different target sets.
SQL Exporter supports TLS and Basic Authentication. This enables better control of the various HTTP endpoints.
To use TLS and/or Basic Authentication, you need to pass a configuration file using the --web.config.file
parameter.
The format of the file is described in the
exporter-toolkit repository.
SQL Exporter started off as an exporter for Microsoft SQL Server, for which no reliable exporters exist. But what is the point of a configuration driven SQL exporter, if you're going to use it along with 2 more exporters with wholly different world views and configurations, because you also have MySQL and PostgreSQL instances to monitor?
A couple of alternative database agnostic exporters are available:
However, they both do the collection at fixed intervals, independent of Prometheus scrapes. This is partly a philosophical issue, but practical issues are not all that difficult to imagine:
- jitter;
- duplicate data points;
- collected but not scraped data points.
The control they provide over which labels get applied is limited, and the base label set spammy. And finally, configurations are not easily reused without copy-pasting and editing across jobs and instances.