xpload provides a library and a CLI tool to communicate with and manage conditions databases with externally stored payloads. A conditions database supports retrievals of version-controlled payload data for specific time intervals requested by a client.

Prerequisites

• C++17, gcc 8.5
• CMake 3.20
• libcurl 7.79.1
• python 3.8

Quick Start

Get the code

git clone https://github.com/bnlnpps/xpload.git

Configure and build the package

cmake -S xpload -B build -DCMAKE_INSTALL_PREFIX=<install_prefix>
cmake --build build

Install the package

cmake --install build

Usage

CLI tool

The entries in the database can be managed with a command line utility xpl. Let's say you would like to add two payload files payload1.data and payload2.data which belong to two groups associated with some subsystems or running conditions that we will refer to as domain1 and domain2 respectively. In turn, the both of the domains can be associated with a label which we will call tag1 in this example. Assigning a tag will make it easy to fetch multiple payloads for various subsystems associated with it.

xpl add tag tag1 --type tag1_type --status tag1_status --domains domain1 domain2
xpl add pil tag1 domain1 /tmp/payload1.data --start 11 --end 33
xpl add pil tag1 domain2 /tmp/payload2.data --start 22 --end 33
xpl push

Existing entries can be listed with the following commands:

xpl show tags
xpl show domains

Finally, we can query the database with a specific time to see if there is a payload file available for the matching interval:

xpl fetch tag1
xpl fetch tag1 --domain domain2
xpl fetch tag1 --treq 15 --domain domain2
xpl fetch tag1 --treq 15 --domain domain1

In a C++ client

We provide a basic example implementing a C++ client that can be found in example/xclient.cpp. Assuming the installation steps for the xpload package were followed in the Quick start section one can simply compile the example from the source directory:

cd example
cmake -S . -B build
cmake --build build
./build/xclient

Configuration

A number of configuration files with database connection details can be found in the config/ subdirectory. The users can modify the existing ones or provide their own. It is easy to switch between different configuration files using their base name and the -c option. For example, to use dev.json or test.json one can respectively specify the command line arguments as:

xpl -c dev show tags
xpl -c test fetch sometag

Similarly, with the C++ interface one pass a name to the Configurator class as:

xpload::Configurator config("test");

When the xpload package is installed it looks for a configuration file in <install_prefix> which is the preferred behavior in production environment. For testing and debugging purposes this can be overridden by placing a configuration file in the current directory or by setting the XPLOAD_CONFIG_DIR environment variable to where your configuration files reside.