使用grafana展示mongodb数据库时间序列内容
1. 概述
默认情况下，grafana是不支持显示mongodb数据库的内容。因为mongodb默认是没有时间字段，如果要想让grafana支持时间序列的展示，需要在插入数据时设置时间字段。
2. 设计架构
3. simplejson插件
grafana默认支持的datasource有Graphite, InfluxDB, OpenTSDB, Prometheus, Elasticsearch, CloudWatch。但是也有很多DataSource以插件的形式存在，由于mongodb是bson形式进行存储，所以我们使用simplejson作为DataSource插件，进行数据转换。
https://grafana.com/plugins/grafana-simple-json-datasource
安装方法：
grafana-cli plugins install grafana-simple-json-datasource
4. mongodb代理
mongodb-proxy需要实现simplejson插件必要的api。
/ 必须返回200 OK,创建datasource时测试。
/search 搜索能够进行查询的label。
/query 查询时间序列。
/annotations 返回注释。
/tag-keys 返回标签键。
/tag-values 返回标签值。
使用swagger生成服务端代码，直接查询数据库。
swagger文件
---
swagger: "2.0"
info:
description: This is a sample mongodb proxy server.
version: 1.0.0
title: Swagger of MongoDB for Grafana plugin
contact:
email: wind.kaisa@gmail.com
license:
name: MIT License
url: https://mit-license.org/
host: localhost:8080
basePath: /
consumes:
- application/json
produces:
- application/json
tags:
- name: SimpleJSON
description: Operations about SimpleJSON
schemes:
- http
paths:
/:
get:
tags:
- SimpleJSON
security: []
summary: test connection
description: should return 200 ok. Used for "Test connection" on the datasource config page.
operationId: TestDatasource
responses:
200:
description: connection successfully.
/search:
post:
tags:
- SimpleJSON
security: []
summary: find metric options
description: used by the find metric options on the query tab in panels.
operationId: MetricFindQuery
parameters:
- in: body
name: options
description: The options to query.
schema:
$ref: '#/definitions/Target'
responses:
200:
description: find metric options successfully.
schema:
type: object
/annotations:
post:
tags:
- SimpleJSON
security: []
summary: get annotations
description: used by dashboards to get annotations.
operationId: AnnotationQuery
parameters:
- in: body
name: options
description: The options to query.
schema:
$ref: '#/definitions/Target'
responses:
200:
description: get annotations successfully.
schema:
$ref: '#/definitions/Annotations'
/query:
post:
tags:
- SimpleJSON
security: []
summary: query data
description: used by panels to get data
operationId: Query
parameters:
- in: body
name: options
description: The options to query.
schema:
$ref: '#/definitions/Query'
responses:
200:
description: query data successfully.
schema:
$ref: '#/definitions/Timeseries'
definitions:
Query:
description: query data requests.
type: object
properties:
range:
$ref: '#/definitions/Range'
interval:
type: string
intervalMs:
type: integer
targets:
type: array
items:
$ref: '#/definitions/Target'
format:
type: string
enum:
- json
default: json
maxDataPoints:
type: integer
Target:
description: data target.
type: object
properties:
target:
type: string
refId:
type: string
type:
type: string
enum:
- timeserie
- table
default: timeserie
Annotations:
description: encodes the information provided by Grafana in its requests.
type: object
properties:
range:
$ref: '#/definitions/Range'
annotation:
$ref: '#/definitions/Annotation'
Range:
description: Range specifies the time range the request is valid for.
type: object
properties:
from:
type: string
format: date-time
to:
type: string
format: date-time
Annotation:
description: Annotation is the object passed by Grafana when it fetches annotations.
type: object
properties:
name:
type: string
datasource:
type: string
iconColor:
type: string
enable:
type: boolean
showLine:
type: boolean
query:
type: string
Timeseries:
description: Request object passed to datasource.query function
type: array
items:
$ref: '#/definitions/Timeserie'
Timeserie:
type: object
properties:
target:
type: string
datapoints:
type: array
items:
type: array
items:
type: object
5. mongodb聚合查询
查询数据库生成时间序列需要用到聚合查询
$match匹配要查询的时间段
$group聚合时间段的数据
$substract时间段相减，算出group的时间差
$mod取模
$project字段是否显示，不显示为0，显示为1
$sort排序
db.getCollection('products').aggregate([
{
'$match':{
'created_at': {'$gte': "2019-03-13T10:30:56Z", '$lte': "2019-03-14T09:25:50Z"}
}
},
{
'$group': {
'_id': {
'$subtract': [
{'$toDate': '$created_at'},
{
'$mod': [
{'$toLong': {'$toDate': '$created_at'}},
60 * 60 * 24 * 1000
]
}
]
},
'total': {'$sum': 1}
}
},
{
'$project': { '_id': 0, 'timestamp': '$_id', 'total': 1}
},
{
'$sort': { 'timestamp': 1 }
}
])
转载请注明来源，欢迎对文章中的引用来源进行考证，欢迎指出任何有错误或不够清晰的表达。可以在下面评论区评论，也可以邮件至 wind.kaisa@gmail.com
