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SonaType Nexus
=================

-> Nexus is an Open Source Software (OSS) & It is free.

-> It is used as Artifactory Repository server.

-> It is used to store & retrieve project build artifacts.

		ex : jar, war, docker images etc..

Note: Project artifacts will be stored in artifactory repository server for backup purpose.	

-> Nexus software developed using java language.

-> The current version of nexus is 3.x

Note : The alternate for nexus is JFrog.

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Q) What is difference between Nexus repo and GitHub repo ?
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-> Github is a SCM software which is used to store source code of the project.

-> Nexus is an Artifact Repository which is used to store build artifacts (jar / war)

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Q) When we should store project artifact into nexus ?
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-> After build and before deployment

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Nexus Setup
=============

https://github.com/ashokitschool/DevOps-Documents/blob/main/07-Nexus-Setup-Docker.md


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Working with Nexus Repository
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=> In nexus server, we can create 2 types of repositories to store project artifacts.

		1) snapshot repository

		2) release repository

-> If project is under development then that project build artifacts will be stored into snapshot repository.

-> If project development completed and released to production then that project build artifacts will be stored to release repository.


Note: Based on <version/> name available in project pom.xml file it will decide artifacts should be stored into which repository.

	<version>0.0.1-SNAPSHOT</version> => It will go to snapshot repository

	<version>RELEASE-1.0</version> => It will go release repository


-> Create Repositories by selecting "Maven 2 (Hosted)"

		- select policy

-> After repositories created note down repo urls like below

	Snapshot repo url : http://3.6.41.58:8081/repository/ashokit_snapshot_repo/

	Release repo url : http://3.6.41.58:8081/repository/ashokit_release_repo/


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Integrate Maven App with Nexus (Manual process)
==================================================

## Step-0 :  Clone git repository : https://github.com/ashokitschool/SB-REST-H2-DB-APP

## Step-1:  Nexus Repos details we will configure in project pom.xml  file like below

  <distributionManagement> 
		<repository>
			<id>nexus</id>
			<name>Ashok IT Releases Nexus Repo</name>
			<url>http://3.6.41.58:8081/repository/ashokit_release_repo/</url>
		</repository>
		
		<snapshotRepository>
			<id>nexus</id>
			<name>Ashok IT Snapshots Nexus Repo</name>
			<url>http://3.6.41.58:8081/repository/ashokit_snapshot_repo/</url>
		</snapshotRepository>	
  </distributionManagement>

## Step-2:  Nexus Server Credentials will be configured in Maven "settings.xml" file

	#### Maven setup in windows : https://www.youtube.com/watch?v=hV1OWzYpzxo

		Maven Location : C:\apache-maven-3.8.5\conf

-> In settings.xml file, under <servers> tag add below <server> tag

	<server>
		<id>nexus</id>
		<username>admin</username>
		<password>admin@123</password>
	</server>


## Step-3:  Once these details are configured then we can run below maven goal to upload build artifacts to Nexus Server

	$ mvn clean deploy

Note: When we execute maven deploy goal, internally it will execute 'compile + test + package + install + deploy' goals.

##################
Remote Repository 
##################

-> Remote repository used for maintaining shared libraries 
   (common jars required for multiple projects in the company)

-> If we want to use few jars files in multiple projects in the company then we will use Remote Repository to store those jars (libraries).

-> Remote repository is specific to our company projects.

-> Create remote repo in nexus and upload a jar file 

	-> Go to Repositories
	-> Create New Repository
	-> Choose Maven (Hosted) Repository
	-> Give a name for Repository (Ex: ashokit-remote-repository) & Complete the process


Note: With above steps Remote Repository got created.


Remote Repo URL : http://65.2.38.55:8081/repository/ashokit_remote_repo/	


-> Go to BrowseSection
-> Select Remote Repository (By default it is empty)
-> Click on Upload Component
-> Upload Jar file and give groupId, artifactId and Version		

	Note: Give extension as jar

	groupId : in.ashokit
	artifactId : pwd-utils
	version : RELEASE-1.0	

	-> Select generat pom file and give package type as pom

=> Take dependency details of uploaded shared library (jar file) and add it as a dependency in project pom.xml file	like below

<dependency>
  <groupId>in.ashokit</groupId>
  <artifactId>pwd-utils</artifactId>
  <version>RELEASE-1.0</version>
</dependency>

-> We need to add Remote Repository Details in pom.xml above <dependencies/> tag

		<repositories>
			<repository>
				<id>nexus</id>
				<url>http://15.206.128.43:8081/repository/ashokit-remote-repo/</url>
			</repository>
		</repositories>

-> After adding the remote repository details in pom.xml then execute maven package goal and see dependency is downloading from nexus repo or not.

		$ mvn clean package


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How to resolve HTTP Mirror Block Issue ?
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=> Make below change in Maven/conf/settings.xml

<mirror>
      <id>maven-default-http-blocker</id>
      <mirrorOf>dummy</mirrorOf>
      <name>Pseudo repository to mirror external repositories initially using HTTP.</name>
      <url>http://0.0.0.0/</url>
      <blocked>false</blocked>
</mirror>


===============
Nexus Summary
===============

1) What is Nexus and Why we need to go for Nexus ?

2) How to setup Nexus Server in Linux 

3) How to create Repositories in Nexus (snapshot & release)

4) How to upload build artifacts into Nexus Repositories

5) What are Shared Libraries ?

6) How to create Remote Repository ?

7) How to upload Shared Libraries into remote repository

8) How to configure remote repository in pom.xml file