Learn to implement microservices across a range of common tech stacks.

Scalability & System Design for Developers

In this module, we’ll look at some fundamental concepts for implementing microservices. Within each concept, learn about the different technologies used to implement it. The technologies include front-end integration with Edge Side Includes (ESI), asynchronous microservices with Kafka and REST feeds, synchronous microservices with the Netflix stack, and Consul, Docker, Kubernetes, Cloud Foundry. Each technology is described and then demonstrated with real code.

Microservice Architecture: Practical Implementation

# Introduction

For each microservice, Apache httpd must have an entry in its configuration file. For this,
[Consul Template](https://github.com/hashicorp/consul-template) can be
used. 

In the example, the `00-default.ctmpl` file is used as a
template to create the Apache httpd configuration. It is written in
the [Consul Templating Language](https://github.com/hashicorp/consul-template#templating-language).
For each microservice, it creates an entry that distributes the load
between the instances and redirects external requests to these
instances.



# The template

The essential part is:


~~~~~~~~
{{range services}}

<Proxy balancer://{{.Name}}>
{{range service .Name}}  BalancerMember http://{{.Address}}:{{.Port}}
{{end}}
</Proxy>
  ProxyPass        /{{.Name}} balancer://{{.Name}}
  ProxyPassReverse /{{.Name}} balancer://{{.Name}}

{{end}}
~~~~~~~~



- The Consul Template API functions are enclosed in `{{` and `}}`. 
- For
each service a configuration is generated with `{{range service}}`. 
- It contains a reverse proxy that is configured with the `<Proxy>` element and the `Name` of the microservice. 
- This element contains the microservice instances as `BalancerMember` with the `Address` and `Port` of each instance for distributing the load between the microservice instances.
- The end is formed by `ProxyPass` and `ProxyPassReverse` which, likewise, belong to the reverse proxy.

In this lesson, we'll discuss Consul Templates.
