KubeMQ Targets

KubeMQ Targets connects KubeMQ Message Broker with external systems and cloud services.
KubeMQ Targets allows us to build a message-based microservices architecture on Kubernetes with minimal efforts and without developing connectivity interfaces between KubeMQ Message Broker and external systems such as databases, cache, messaging, and REST-base APIs.
Key Features:
Runs anywhere  - Kubernetes, Cloud, on-prem, anywhere
Stand-alone - small docker container / binary
Single Interface - One interface all the services
Any Service - Support all major services types (databases, cache, messaging, serverless, HTTP, etc.)
Plug-in Architecture Easy to extend, easy to connect
Middleware Supports - Logs, Metrics, Retries, and Rate Limiters
Easy Configuration - simple yaml file builds your topology
Concepts
KubeMQ Targets building blocks are:
Binding
Source
Target
Request/Response
Binding
Binding is a 1:1 connection between Source and Target. Every Binding runs independently.
binding
Target
Target is an external service that exposes an API allowing interacting and serve his functionalists with other services.
Targets can be Cache systems such as Redis and Memcached, SQL Databases such as Postgres and MySql, and even an HTTP generic Rest interface.
KubeMQ Targets integrate each one of the supported targets and service requests based on the request data.
Source
The source is a KubeMQ connection (in subscription mode), which listens to requests from services and route them to the appropriate target for action, and return a response if needed.
Request / Response
concept
Request
A request is an object that sends to a designated target with metadata and data fields, which contains the needed information to perform the requested data.
Request Object Structure
Field
Type
Description
metadata
string, string object
contains metadata information for action
data
bytes array
contains raw data for action
Example
Request to get a data from Redis cache for the key "log"
{
  "metadata": {
    "method": "get",
    "key": "log"
  },
  "data": null
}
Response
The response is an object that sends back as a result of executing an action in the target
Response Object Structure
Field
Type
Description
metadata
string, string object
contains metadata information result for action
data
bytes array
contains raw data result
is_error
bool
indicate if the action ended with an error
error
string
contains error information if any
Example
Response received on request to get the data stored in Redis for key "log"
{
  "metadata": {
    "result": "ok",
    "key": "log"
  },
  "data": "SU5TRVJUIElOVE8gcG9zdChJRCxUSVRMRSxDT05URU5UKSBWQUxVRVMKCSAgICAgICAgICAgICAgICAgICAgICA"
}
Middlewares
In bindings configuration, KubeMQ Bridges supports middleware setting for each pair of source and target bindings.
These properties contain middleware information settings as follows:
Logs Middleware
KubeMQ Bridges supports level based logging to console according to as follows:
Property
Description
Possible Values
log_level
log level setting
"debug","info","error"
​
​
"" - indicate no logging on this bindings
An example for only error level log to console:
bindings:
  - name: sample-binding 
    properties: 
      log_level: error
    sources:
    ......
Retry Middleware
KubeMQ Bridges supports Retries' target execution before reporting of error back to the source on failed execution.
Retry middleware settings values:
Property
Description
Possible Values
retry_attempts
how many retries before giving up on target execution
default - 1, or any int number
retry_delay_milliseconds
how long to wait between retries in milliseconds
default - 100ms or any int number
retry_max_jitter_milliseconds
max delay jitter between retries
default - 100ms or any int number
retry_delay_type
type of retry delay
"back-off" - delay increase on each attempt
​
​
"fixed" - fixed time delay
​
​
"random" - random time delay
An example for 3 retries with back-off strategy:
bindings:
  - name: sample-binding 
    properties: 
      retry_attempts: 3
      retry_delay_milliseconds: 1000
      retry_max_jitter_milliseconds: 100
      retry_delay_type: "back-off"
    sources:
    ......
Rate Limiter Middleware
KubeMQ Sources support a Rate Limiting of target executions.
Rate Limiter middleware settings values:
Property
Description
Possible Values
rate_per_second
how many executions per second will be allowed
0 - no limitation
​
​
1 - n integer times per second
An example for 100 executions per second:
bindings:
  - name: sample-binding 
    properties: 
      rate_per_second: 100
    source:
    ......

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KubeMQ Sources

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Rate Limiter Middleware