add proxysql service monitoring plugin (netdata#703)

README.md

@@ -81,6 +81,7 @@ Go.d.plugin is shipped with Netdata.
 | [postgres](https://github.com/netdata/go.d.plugin/tree/master/modules/postgres)                     |          PostgreSQL           |
 | [powerdns](https://github.com/netdata/go.d.plugin/tree/master/modules/powerdns)                     | PowerDNS Authoritative Server |
 | [powerdns_recursor](https://github.com/netdata/go.d.plugin/tree/master/modules/powerdns_recursor)   |       PowerDNS Recursor       |
+| [proxysql](https://github.com/netdata/go.d.plugin/tree/master/modules/proxysql)                     |           ProxySQL            |
 | [pulsar](https://github.com/netdata/go.d.plugin/tree/master/modules/portcheck)                      |         Apache Pulsar         |
 | [rabbitmq](https://github.com/netdata/go.d.plugin/tree/master/modules/rabbitmq)                     |           RabbitMQ            |
 | [redis](https://github.com/netdata/go.d.plugin/tree/master/modules/redis)                           |             Redis             |

config/go.d/proxysql.conf

@@ -0,0 +1,102 @@
+# netdata go.d.plugin configuration for proxysql
+#
+# This file is in YAML format. Generally the format is:
+#
+# name: value
+#
+# There are 2 sections:
+#  - GLOBAL
+#  - JOBS
+#
+#
+# [ GLOBAL ]
+# These variables set the defaults for all JOBs, however each JOB may define its own, overriding the defaults.
+#
+# The GLOBAL section format:
+# param1: value1
+# param2: value2
+#
+# Currently supported global parameters:
+#  - update_every
+#    Data collection frequency in seconds. Default: 1.
+#
+#  - autodetection_retry
+#    Re-check interval in seconds. Attempts to start the job are made once every interval.
+#    Zero means not to schedule re-check. Default: 0.
+#
+#  - priority
+#    Priority is the relative priority of the charts as rendered on the web page,
+#    lower numbers make the charts appear before the ones with higher numbers. Default: 70000.
+#
+#
+# [ JOBS ]
+# JOBS allow you to collect values from multiple sources.
+# Each source will have its own set of charts.
+#
+# IMPORTANT:
+#  - Parameter 'name' is mandatory.
+#  - Jobs with the same name are mutually exclusive. Only one of them will be allowed running at any time.
+#
+# This allows autodetection to try several alternatives and pick the one that works.
+# Any number of jobs is supported.
+#
+# The JOBS section format:
+#
+# jobs:
+#   - name: job1
+#     param1: value1
+#     param2: value2
+#
+#   - name: job2
+#     param1: value1
+#     param2: value2
+#
+#   - name: job2
+#     param1: value1
+#
+#
+# [ List of JOB specific parameters ]:
+#  - dsn
+#    Data Source Name.
+#    Format: [username[:password]@][protocol[(address)]]/
+#    Full description: https://github.com/go-sql-driver/mysql#dsn-data-source-name
+#    Syntax:
+#     dsn: stats:stats@tcp(127.0.0.1:6032)/
+#
+#  - my.cnf
+#    Specifies my.cnf file to read connection parameters from under the [client] section
+#    Syntax:
+#     my.cnf: '/etc/my.cnf'
+#
+#  - timeout
+#    Query timeout in seconds. Default 1 second.
+#    Syntax:
+#      timeout: 1
+#
+#
+# [ JOB defaults ]:
+#  No parameters
+#
+#
+# [ JOB mandatory parameters ]:
+#  - name
+#  - dsn
+# ------------------------------------------------MODULE-CONFIGURATION--------------------------------------------------
+
+# update_every: 1
+# autodetection_retry: 0
+# priority: 70000
+# timeout: 1
+
+jobs:
+  # my.cnf
+  - name: local
+    my.cnf: '/etc/my.cnf'
+
+  # stats
+  - name: local
+    dsn: stats:stats@tcp(127.0.0.1:6032)/
+
+  - name: local
+    dsn: stats:stats@tcp([::1]:6032)/
+

modules/init.go

@@ -53,6 +53,7 @@ import (
 	_ "github.com/netdata/go.d.plugin/modules/powerdns"
 	_ "github.com/netdata/go.d.plugin/modules/powerdns_recursor"
 	_ "github.com/netdata/go.d.plugin/modules/prometheus"
+	_ "github.com/netdata/go.d.plugin/modules/proxysql"
 	_ "github.com/netdata/go.d.plugin/modules/pulsar"
 	_ "github.com/netdata/go.d.plugin/modules/rabbitmq"
 	_ "github.com/netdata/go.d.plugin/modules/redis"

modules/proxysql/README.md

@@ -0,0 +1,105 @@
+<!--
+title: "ProxySQL monitoring with Netdata"
+description: "Monitor connections, slow queries, lagging, backends status and more with zero configuration and per-second metric granularity."
+custom_edit_url: https://github.com/netdata/go.d.plugin/edit/master/modules/proxysql/README.md
+sidebar_label: "ProxySQL"
+-->
+
+# ProxySQL monitoring with Netdata
+
+[`ProxySQL`](https://www.proxysql.com/) is an open-source proxy for mySQL.
+
+This module monitors one or more `ProxySQL` servers, depending on your configuration.
+
+## Requirements
+
+Executed queries:
+
+- `SELECT Variable_Name, Variable_Value FROM global_variables;`
+- `SELECT Variable_Name, Variable_Value FROM stats_memory_metrics;`
+- `SELECT * FROM stats_mysql_commands_counters;`
+- `SELECT Variable_Name, Variable_Value FROM stats_mysql_global;`
+- `SELECT * FROM stats_mysql_users;`
+
+
+Netdata uses `stats` username and password which is enabled by default
+
+## Charts
+
+It produces the following charts:
+
+- Uptime in `seconds`
+- Questions in `questions`
+- Active transactions in `transanctions`
+- Slow queries in `queries`
+- Backend lagging during query in `backends`
+- Backend offline during query in `backends`
+- Generated error packets in `packets/s`
+- Max connection timeouts in `connections`
+- Client connections in `connections`
+- Server connections in `connections`
+- Query time in `nanoseconds`
+- ProxySQL commands in `commands`
+- Connection  pool requests in `connections`
+- Connection  pool connections in `connections`
+- Mysql monitor threads in `threads`
+- Mysql thread workers in `workers`
+- Network in `bytes/s`
+- Query cache in `number of entries`
+- Prepared statements in `prepared statements`
+- MySQL max allowed packet in `bytes`
+- Memory in `bytes`
+- Jemalloc memory in `bytes`
+- MySQL command counts in `commands`
+- MySQL user connections in `connections` 
+
+
+## Configuration
+
+Edit the `go.d/proxysql.conf` configuration file using `edit-config` from the
+Netdata [config directory](https://learn.netdata.cloud/docs/configure/nodes), which is typically at `/etc/netdata`.
+
+```bash
+cd /etc/netdata # Replace this path with your Netdata config directory
+sudo ./edit-config go.d/proxysql.conf
+```
+
+[DSN syntax in details](https://github.com/go-sql-driver/mysql#dsn-data-source-name).
+
+```yaml
+jobs:
+  - name: local
+    dsn: '[username[:password]@][protocol[(address)]]/'
+    # username:password@protocol(address)/
+    # Examples:
+    # - name: remote
+    #   dsn: stats:stats@localhost/
+```
+
+For all available options see
+module [configuration file](https://github.com/netdata/go.d.plugin/blob/master/config/go.d/proxysql.conf).
+
+## Troubleshooting
+
+To troubleshoot issues with the `proxysql` collector, run the `go.d.plugin` with the debug option enabled. The output
+should give you clues as to why the collector isn't working.
+
+- Navigate to the `plugins.d` directory, usually at `/usr/libexec/netdata/plugins.d/`. If that's not the case on
+  your system, open `netdata.conf` and look for the `plugins` setting under `[directories]`.
+
+  ```bash
+  cd /usr/libexec/netdata/plugins.d/
+  ```
+
+- Switch to the `netdata` user.
+
+  ```bash
+  sudo -u netdata -s
+  ```
+
+- Run the `go.d.plugin` to debug the collector:
+
+  ```bash
+  ./go.d.plugin -d -m proxysql
+  ```
+