  We present TXPipe, a modular, automated and reproducible pipeline for
ingesting catalog data and performing all the calculations required to obtain
quality-assured two-point measurements of lensing and clustering, and their
covariances, with the metadata necessary for parameter estimation. The pipeline
is developed within the Rubin Observatory Legacy Survey of Space and Time
(LSST) Dark Energy Science Collaboration (DESC), and designed for cosmology
analyses using LSST data. In this paper, we present the pipeline for the
so-called 3x2pt analysis -- a combination of three two-point functions that
measure the auto- and cross-correlation between galaxy density and shapes. We
perform the analysis both in real and harmonic space using TXPipe and other
LSST-DESC tools. We validate the pipeline using Gaussian simulations and show
that it accurately measures data vectors and recovers the input cosmology to
the accuracy level required for the first year of LSST data under this
simplified scenario. We also apply the pipeline to a realistic mock galaxy
sample extracted from the CosmoDC2 simulation suite (Korytov et al. 2019).
TXPipe establishes a baseline framework that can be built upon as the LSST
survey proceeds. Furthermore, the pipeline is designed to be easily extended to
science probes beyond the 3x2pt analysis.
