1. Classic LOCKSS Development

Note

This page is under construction.

The code base of the Classic LOCKSS system (version 1.x) is contained in a single Git repository, https://github.com/lockss/lockss-daemon.

1.1. Prerequisites

To do development work with the Classic LOCKSS system (version 1.x), you will need:

• Git

• Java 8 Development Kit (JDK 8), for example OpenJDK 8

• Apache Ant

• Python 3, invoked as python3

• Some scripts require Python 2.7, invoked as python2

• Some runtime contexts that process split Zip files and some unit tests require the zip program (zip and unzip are installed by default on most Linux systems).

1.1.1. Installing Git

You can check if Git is installed on your system by typing git --version at the command line and seeing if you get a valid response. If you need to install Git, select your operating system below and follow the instructions (as root, except for Homebrew on MacOS):

AlmaLinux OS

To install Git, run this Dnf command (as root):

dnf --assumeyes install git

Arch Linux

To install Git, run this Pacman command (as root):

pacman -Sy --noconfirm git

CentOS

CentOS Stream 8-9

To install Git, run this Dnf command (as root):

dnf --assumeyes install git

CentOS 8

To install Git, run this Dnf command (as root):

dnf --assumeyes install git

CentOS 7

To install Git, run this Yum command (as root):

yum --assumeyes install git

Debian

To install Git, run these Apt commands (as root):

apt update

apt install --assume-yes git

EuroLinux

EuroLinux 8-9

To install Git, run this Dnf command (as root):

dnf --assumeyes install git

EuroLinux 7

To install Git, run this Yum command (as root):

yum --assumeyes install git

Fedora Linux

To install Git, run this Dnf command (as root):

dnf --assumeyes install git

Linux Mint

To install Git, run these Apt commands (as root):

apt update

apt install --assume-yes git

MacOS

Homebrew

To install Git, run this Homebrew command:

brew install git

MacPorts

To install Git, run this MacPorts command (as root):

sudo port install git

OpenSUSE

OpenSUSE Leap 15

To install Git, run these Zypper commands (as root):

zypper refresh

zypper --non-interactive install git

OpenSUSE Tumbleweed

To install Git, run these Zypper commands (as root):

zypper refresh

zypper --non-interactive install git

Oracle Linux

Oracle Linux 8-9

To install Git, run this Dnf command (as root):

dnf --assumeyes install git

Oracle Linux 7

To install Git, run this Yum command (as root):

yum --assumeyes install git

RHEL

RHEL 7

To install Git, run this Yum command (as root):

yum --assumeyes install git

RHEL 8-9

To install Git, run this Dnf command (as root):

dnf --assumeyes install git

Rocky Linux

To install Git, run this Dnf command (as root):

dnf --assumeyes install git

Scientific Linux

To install Git, run this Yum command (as root):

yum --assumeyes install git

Ubuntu

To install Git, run these Apt commands (as root):

apt update

apt install --assume-yes git

1.1.2. Installing the Java Development Kit

1. You can check if a Java Development Kit (JDK) is installed on your system by typing javac -version at the command line and seeing if you get a valid response. (The version numbers output by Java 8 software sometimes use the notation 1.8, for example 1.8.0_382.)

   If you need to install a JDK, we recommend OpenJDK; select your operating system below and follow the instructions (as root, except for Homebrew on MacOS):

   AlmaLinux OS

   To install OpenJDK, run this Dnf command (as root):

   dnf --assumeyes install java-1.8.0-openjdk-devel
   

   Arch Linux

   To install OpenJDK, run this Pacman command (as root):

   pacman -Sy --noconfirm jdk8-openjdk
   

   CentOS

   CentOS Stream 8-9

   To install OpenJDK, run this Dnf command (as root):

   dnf --assumeyes install java-1.8.0-openjdk-devel
   

   CentOS 8

   To install OpenJDK, run this Dnf command (as root):

   dnf --assumeyes install java-1.8.0-openjdk-devel
   

   CentOS 7

   To install OpenJDK, run this Yum command (as root):

   yum --assumeyes install java-1.8.0-openjdk-devel
   

   Debian

   To install OpenJDK, run these Apt commands (as root):

   apt update
   
   apt install --assume-yes openjdk-8-jdk
   

   EuroLinux

   EuroLinux 8-9

   To install OpenJDK, run this Dnf command (as root):

   dnf --assumeyes install java-1.8.0-openjdk-devel
   

   EuroLinux 7

   To install OpenJDK, run this Yum command (as root):

   yum --assumeyes install java-1.8.0-openjdk-devel
   

   Fedora Linux

   To install OpenJDK, run this Dnf command (as root):

   dnf --assumeyes install java-1.8.0-openjdk-devel
   

   Linux Mint

   To install OpenJDK, run these Apt commands (as root):

   apt update
   
   apt install --assume-yes openjdk-8-jdk
   

   MacOS

   Homebrew

   To install OpenJDK, run this Homebrew command:

   brew install openjdk@8
   

   Note

   You may be directed to create symlinks and/or update your PATH to make OpenJDK visible to your system, for instance:

   For the system Java wrappers to find this JDK, symlink it with
     sudo ln -sfn /usr/local/opt/openjdk@8/libexec/openjdk.jdk /Library/Java/JavaVirtualMachines/openjdk-8.jdk
   
   openjdk@8 is keg-only, which means it was not symlinked into /usr/local,
   because this is an alternate version of another formula.
   
   If you need to have openjdk@8 first in your PATH, run:
     echo 'export PATH="/usr/local/opt/openjdk@8/bin:$PATH"' >> ~/.zshrc
   
   For compilers to find openjdk@8 you may need to set:
     export CPPFLAGS="-I/usr/local/opt/openjdk@8/include"
   

   MacPorts

   To install OPenJDK, run this MacPorts command (as root):

   sudo port install openjdk
   

   OpenSUSE

   OpenSUSE Leap 15

   To install OpenJDK, run these Zypper commands (as root):

   zypper refresh
   
   zypper --non-interactive install java-1_8_0-openjdk-devel
   

   OpenSUSE Tumbleweed

   To install OpenJDK, run these Zypper commands (as root):

   zypper refresh
   
   zypper --non-interactive install java-1_8_0-openjdk-devel
   

   Oracle Linux

   Oracle Linux 8-9

   To install OpenJDK, run this Dnf command (as root):

   dnf --assumeyes install java-1.8.0-openjdk-devel
   

   Oracle Linux 7

   To install OpenJDK, run this Yum command (as root):

   yum --assumeyes install java-1.8.0-openjdk-devel
   

   RHEL

   RHEL 8-9

   To install OpenJDK, run this Dnf command (as root):

   dnf --assumeyes install java-1.8.0-openjdk-devel
   

   RHEL 7

   To install OpenJDK, run this Yum command (as root):

   yum --assumeyes install java-1.8.0-openjdk-devel
   

   Rocky Linux

   To install OpenJDK, run this Dnf command (as root):

   dnf --assumeyes install java-1.8.0-openjdk-devel
   

   Scientific Linux

   To install OpenJDK, run this Yum command (as root):

   yum --assumeyes install java-1.8.0-openjdk-devel
   

   Ubuntu

   To install OpenJDK, run these Apt commands (as root):

   apt update
   
   apt install --assume-yes openjdk-8-jdk
   

2. Set the JAVA_HOME environment variable to the directory in which the JDK is installed, for example /usr/lib/jvm/java-8-openjdk or similar for Linux or /usr/local/opt/openjdk@8/libexec/openjdk.jdk/Home for MacOS with Homebrew. It is expected that the file $JAVA_HOME/lib/tools.jar exists.

1.1.3. Installing Apache Ant

You can check if Ant is installed on your system by typing ant -version at the command line and seeing if you get a valid response. If you need to install Ant, select your operating system below and follow the instructions (as root, except for Homebrew on MacOS):

AlmaLinux OS

To install Ant, run this Dnf command (as root):

dnf --assumeyes install ant

Arch Linux

To install Ant, run this Pacman command (as root):

pacman -Sy --noconfirm ant

CentOS

CentOS Stream 8-9

To install Ant, run this Dnf command (as root):

dnf --assumeyes install ant

CentOS 8

To install Ant, run this Dnf command (as root):

dnf --assumeyes install ant

CentOS 7

To install Ant, run this Yum command (as root):

yum --assumeyes install ant

Debian

To install Ant, run these Apt commands (as root):

apt update

apt install --assume-yes ant

EuroLinux

EuroLinux 8-9

To install Ant, run this Dnf command (as root):

dnf --assumeyes install ant

EuroLinux 7

To install Ant, run this Yum command (as root):

yum --assumeyes install ant

Fedora Linux

To install Ant, run this Dnf command (as root):

dnf --assumeyes install ant

Linux Mint

To install Ant, run these Apt commands (as root):

apt update

apt install --assume-yes ant

MacOS

Homebrew

To install Ant, run this Homebrew command:

brew install ant

MacPorts

To install Ant, run this MacPorts command (as root):

sudo port install apache-ant

OpenSUSE

OpenSUSE Leap 15

To install Ant, run these Zypper commands (as root):

zypper refresh

zypper --non-interactive install ant

OpenSUSE Tumbleweed

To install Ant, run these Zypper commands (as root):

zypper refresh

zypper --non-interactive install ant

Oracle Linux

Oracle Linux 8-9

To install Ant, run this Dnf command (as root):

dnf --assumeyes install ant

Oracle Linux 7

To install Ant, run this Yum command (as root):

yum --assumeyes install ant

RHEL

RHEL 8-9

To install Ant, run this Dnf command (as root):

dnf --assumeyes install ant

RHEL 7

To install Ant, run this Yum command (as root):

yum --assumeyes install ant

Rocky Linux

To install Ant, run this Dnf command (as root):

dnf --assumeyes install ant

Scientific Linux

To install Ant, run this Yum command (as root):

yum --assumeyes install ant

Ubuntu

To install Ant, run these Apt commands (as root):

apt update

apt install --assume-yes ant

1.1.4. Cloning the Git Repository

To clone the lockss-daemon repository from Git, use one of these commands:

# GitHub account with SSH key
git clone git@github.com:lockss/lockss-daemon

# Anonymous access
git clone https://github.com/lockss/lockss-daemon

This will create a lockss-daemon directory.

1.1.5. JUnit Prerequisites

JUnit 3.8.1 is included is included in the LOCKSS source distribution to run unit tests, but the Ant targets that invoke JUnit (test-xxx) require the JUnit JAR to be on Ant's CLASSPATH. The easiest way to do this is to copy lib/junit.jar (relative to the root of the lockss-daemon Git tree) into Ant's lib directory (relative to its installation directory on the system).

1.2. Tour of lockss-daemon

The main components of the lockss-daemon repository are as follows:

• build.xml is the Ant build file. Type ant -projecthelp (or ant -p) will output a list of available build targets. The lib directory contains Java (JAR) dependencies for the project at large.

• The src tree contains the source code of the LOCKSS system proper, and test/src its unit tests. The ant/src tree contains the source code for an ancillary prerequisite.

• The plugins/src tree contains the source code of plugins written by the LOCKSS Program to support the preservation activities of LOCKSS networks such as the Global LOCKSS Network (GLN) and the CLOCKSS Archive, and plugins/test/src the unit tests.

• The tools/src tree contains the source code of ancillary tools sometimes used in the context of LOCKSS development, and tools/test/src the unit tests.

• The tdb directory contains the archival unit (AU) inventory of content managed by the LOCKSS Program on behalf of various LOCKSS networks such as the GLN and CLOCKSS.

• The scripts and test/scripts directories contains scripts and tools used for TDB file processing, SOAP Web services, and more.

• The test/frameworks tree contains multiple testing frameworks, to bring up one or more instance of the (classic) LOCKSS system on the local machine for testing or development purposes.