psycopg2-binary should not be used.

[ns-iknox]

As discovered in Issue #185, we should not be using the binary package in a production codebase.
Currently both versions are required in setup.py.

[EMCP]

my installation fails even when I use the binary... unsure how to proceed

$ pip install psycopg2-binary
Requirement already satisfied: psycopg2-binary in /home/emcp/anaconda3/envs/meltano-/lib/python3.8/site-packages (2.9.1)
$ meltano add loader target-postgres
Loader 'target-postgres' already exists in your Meltano project
To add it to your project another time so that each can be configured differently,
add a new plugin inheriting from the existing one with its own unique name:
        meltano add loader target-postgres--new --inherit-from target-postgres

Installing loader 'target-postgres'...
Loader 'target-postgres' could not be installed: failed to install plugin 'target-postgres'.
    ERROR: Command errored out with exit status 1:
     command: /home/emcp/Dev/git/meltano--ib/.meltano/loaders/target-postgres/venv/bin/python -c 'import io, os, sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-wv16bb9e/psycopg2_f2eb0717b4694b6b9e37ca2684759aae/setup.py'"'"'; __file__='"'"'/tmp/pip-install-wv16bb9e/psycopg2_f2eb0717b4694b6b9e37ca2684759aae/setup.py'"'"';f = getattr(tokenize, '"'"'open'"'"', open)(__file__) if os.path.exists(__file__) else io.StringIO('"'"'from setuptools import setup; setup()'"'"');code = f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-pip-egg-info-io9muisp
         cwd: /tmp/pip-install-wv16bb9e/psycopg2_f2eb0717b4694b6b9e37ca2684759aae/
    Complete output (23 lines):
    running egg_info
    creating /tmp/pip-pip-egg-info-io9muisp/psycopg2.egg-info
    writing /tmp/pip-pip-egg-info-io9muisp/psycopg2.egg-info/PKG-INFO
    writing dependency_links to /tmp/pip-pip-egg-info-io9muisp/psycopg2.egg-info/dependency_links.txt
    writing top-level names to /tmp/pip-pip-egg-info-io9muisp/psycopg2.egg-info/top_level.txt
    writing manifest file '/tmp/pip-pip-egg-info-io9muisp/psycopg2.egg-info/SOURCES.txt'
    
    Error: pg_config executable not found.
    
    pg_config is required to build psycopg2 from source.  Please add the directory
    containing pg_config to the $PATH or specify the full executable path with the
    option:
    
        python setup.py build_ext --pg-config /path/to/pg_config build ...
    
    or with the pg_config option in 'setup.cfg'.
    
    If you prefer to avoid building psycopg2 from source, please install the PyPI
    'psycopg2-binary' package instead.
    
    For further information please check the 'doc/src/install.rst' file (also at
    <https://www.psycopg.org/docs/install.html>).
    
    ----------------------------------------
WARNING: Discarding https://files.pythonhosted.org/packages/a8/8f/1c5690eebf148d1d1554fc00ccf9101e134636553dbb75bdfef4f85d7647/psycopg2-2.8.5.tar.gz#sha256=f7d46240f7a1ae1dd95aab38bd74f7428d46531f69219954266d669da60c0818 (from https://pypi.org/simple/psycopg2/) (requires-python:>=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*). Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.
    ERROR: Command errored out with exit status 1:
     command: /home/emcp/Dev/git/meltano--ib/.meltano/loaders/target-postgres/venv/bin/python -c 'import io, os, sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-wv16bb9e/psycopg2_33c9ba163d364687b2cac5026a34af01/setup.py'"'"'; __file__='"'"'/tmp/pip-install-wv16bb9e/psycopg2_33c9ba163d364687b2cac5026a34af01/setup.py'"'"';f = getattr(tokenize, '"'"'open'"'"', open)(__file__) if os.path.exists(__file__) else io.StringIO('"'"'from setuptools import setup; setup()'"'"');code = f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-pip-egg-info-zgi8twhs
         cwd: /tmp/pip-install-wv16bb9e/psycopg2_33c9ba163d364687b2cac5026a34af01/
    Complete output (23 lines):
    running egg_info
    creating /tmp/pip-pip-egg-info-zgi8twhs/psycopg2.egg-info
    writing /tmp/pip-pip-egg-info-zgi8twhs/psycopg2.egg-info/PKG-INFO
    writing dependency_links to /tmp/pip-pip-egg-info-zgi8twhs/psycopg2.egg-info/dependency_links.txt
    writing top-level names to /tmp/pip-pip-egg-info-zgi8twhs/psycopg2.egg-info/top_level.txt
    writing manifest file '/tmp/pip-pip-egg-info-zgi8twhs/psycopg2.egg-info/SOURCES.txt'
    
    Error: pg_config executable not found.
    
    pg_config is required to build psycopg2 from source.  Please add the directory
    containing pg_config to the $PATH or specify the full executable path with the
    option:
    
        python setup.py build_ext --pg-config /path/to/pg_config build ...
    
    or with the pg_config option in 'setup.cfg'.
    
    If you prefer to avoid building psycopg2 from source, please install the PyPI
    'psycopg2-binary' package instead.
    
    For further information please check the 'doc/src/install.rst' file (also at
    <http://initd.org/psycopg/docs/install.html>).
    
    ----------------------------------------
WARNING: Discarding https://files.pythonhosted.org/packages/84/d7/6a93c99b5ba4d4d22daa3928b983cec66df4536ca50b22ce5dcac65e4e71/psycopg2-2.8.4.tar.gz#sha256=f898e5cc0a662a9e12bde6f931263a1bbd350cfb18e1d5336a12927851825bb6 (from https://pypi.org/simple/psycopg2/) (requires-python:>=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*). Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.
    ERROR: Command errored out with exit status 1:
     command: /home/emcp/Dev/git/meltano--ib/.meltano/loaders/target-postgres/venv/bin/python -c 'import io, os, sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-wv16bb9e/psycopg2_eeed467e937c43f3ada000a8efa72192/setup.py'"'"'; __file__='"'"'/tmp/pip-install-wv16bb9e/psycopg2_eeed467e937c43f3ada000a8efa72192/setup.py'"'"';f = getattr(tokenize, '"'"'open'"'"', open)(__file__) if os.path.exists(__file__) else io.StringIO('"'"'from setuptools import setup; setup()'"'"');code = f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-pip-egg-info-sd0q8id0
         cwd: /tmp/pip-install-wv16bb9e/psycopg2_eeed467e937c43f3ada000a8efa72192/
    Complete output (23 lines):
    running egg_info
    creating /tmp/pip-pip-egg-info-sd0q8id0/psycopg2.egg-info
    writing /tmp/pip-pip-egg-info-sd0q8id0/psycopg2.egg-info/PKG-INFO
    writing dependency_links to /tmp/pip-pip-egg-info-sd0q8id0/psycopg2.egg-info/dependency_links.txt
    writing top-level names to /tmp/pip-pip-egg-info-sd0q8id0/psycopg2.egg-info/top_level.txt
    writing manifest file '/tmp/pip-pip-egg-info-sd0q8id0/psycopg2.egg-info/SOURCES.txt'
    
    Error: pg_config executable not found.
    
    pg_config is required to build psycopg2 from source.  Please add the directory
    containing pg_config to the $PATH or specify the full executable path with the
    option:
    
        python setup.py build_ext --pg-config /path/to/pg_config build ...
    
    or with the pg_config option in 'setup.cfg'.
    
    If you prefer to avoid building psycopg2 from source, please install the PyPI
    'psycopg2-binary' package instead.
    
    For further information please check the 'doc/src/install.rst' file (also at
    <http://initd.org/psycopg/docs/install.html>).
    
    ----------------------------------------
WARNING: Discarding https://files.pythonhosted.org/packages/23/7e/93c325482c328619870b6cd09370f6dbe1148283daca65115cd63642e60f/psycopg2-2.8.2.tar.gz#sha256=5cacf21b6f813c239f100ef78a4132056f93a5940219ec25d2ef833cbeb05588 (from https://pypi.org/simple/psycopg2/) (requires-python:>=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*). Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.
    ERROR: Command errored out with exit status 1:
     command: /home/emcp/Dev/git/meltano--ib/.meltano/loaders/target-postgres/venv/bin/python -c 'import io, os, sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-wv16bb9e/psycopg2-binary_d92771c5e2334f4c9da8bce9d3602e91/setup.py'"'"'; __file__='"'"'/tmp/pip-install-wv16bb9e/psycopg2-binary_d92771c5e2334f4c9da8bce9d3602e91/setup.py'"'"';f = getattr(tokenize, '"'"'open'"'"', open)(__file__) if os.path.exists(__file__) else io.StringIO('"'"'from setuptools import setup; setup()'"'"');code = f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-pip-egg-info-u3myz4rg
         cwd: /tmp/pip-install-wv16bb9e/psycopg2-binary_d92771c5e2334f4c9da8bce9d3602e91/
    Complete output (23 lines):
    running egg_info
    creating /tmp/pip-pip-egg-info-u3myz4rg/psycopg2_binary.egg-info
    writing /tmp/pip-pip-egg-info-u3myz4rg/psycopg2_binary.egg-info/PKG-INFO
    writing dependency_links to /tmp/pip-pip-egg-info-u3myz4rg/psycopg2_binary.egg-info/dependency_links.txt
    writing top-level names to /tmp/pip-pip-egg-info-u3myz4rg/psycopg2_binary.egg-info/top_level.txt
    writing manifest file '/tmp/pip-pip-egg-info-u3myz4rg/psycopg2_binary.egg-info/SOURCES.txt'
    
    Error: pg_config executable not found.
    
    pg_config is required to build psycopg2 from source.  Please add the directory
    containing pg_config to the $PATH or specify the full executable path with the
    option:
    
        python setup.py build_ext --pg-config /path/to/pg_config build ...
    
    or with the pg_config option in 'setup.cfg'.
    
    If you prefer to avoid building psycopg2 from source, please install the PyPI
    'psycopg2-binary' package instead.
    
    For further information please check the 'doc/src/install.rst' file (also at
    <http://initd.org/psycopg/docs/install.html>).
    
    ----------------------------------------
WARNING: Discarding https://files.pythonhosted.org/packages/dd/56/c22da10f5a725d61c58a185ec0f803aa2d384646ee8eb83d8ce88ed5edb1/psycopg2-binary-2.7.7.tar.gz#sha256=b19e9f1b85c5d6136f5a0549abdc55dcbd63aba18b4f10d0d063eb65ef2c68b4 (from https://pypi.org/simple/psycopg2-binary/). Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.
    ERROR: Command errored out with exit status 1:
     command: /home/emcp/Dev/git/meltano--ib/.meltano/loaders/target-postgres/venv/bin/python -c 'import io, os, sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-wv16bb9e/psycopg2_fa517cec4ae1412895a4a728da0aeaf4/setup.py'"'"'; __file__='"'"'/tmp/pip-install-wv16bb9e/psycopg2_fa517cec4ae1412895a4a728da0aeaf4/setup.py'"'"';f = getattr(tokenize, '"'"'open'"'"', open)(__file__) if os.path.exists(__file__) else io.StringIO('"'"'from setuptools import setup; setup()'"'"');code = f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-pip-egg-info-bqn353eu
         cwd: /tmp/pip-install-wv16bb9e/psycopg2_fa517cec4ae1412895a4a728da0aeaf4/
    Complete output (23 lines):
    running egg_info
    creating /tmp/pip-pip-egg-info-bqn353eu/psycopg2.egg-info
    writing /tmp/pip-pip-egg-info-bqn353eu/psycopg2.egg-info/PKG-INFO
    writing dependency_links to /tmp/pip-pip-egg-info-bqn353eu/psycopg2.egg-info/dependency_links.txt
    writing top-level names to /tmp/pip-pip-egg-info-bqn353eu/psycopg2.egg-info/top_level.txt
    writing manifest file '/tmp/pip-pip-egg-info-bqn353eu/psycopg2.egg-info/SOURCES.txt'
    
    Error: pg_config executable not found.
    
    pg_config is required to build psycopg2 from source.  Please add the directory
    containing pg_config to the $PATH or specify the full executable path with the
    option:
    
        python setup.py build_ext --pg-config /path/to/pg_config build ...
    
    or with the pg_config option in 'setup.cfg'.
    
    If you prefer to avoid building psycopg2 from source, please install the PyPI
    'psycopg2-binary' package instead.
    
    For further information please check the 'doc/src/install.rst' file (also at
    <http://initd.org/psycopg/docs/install.html>).
    
    ----------------------------------------
WARNING: Discarding https://files.pythonhosted.org/packages/63/54/c039eb0f46f9a9406b59a638415c2012ad7be9b4b97bfddb1f48c280df3a/psycopg2-2.7.7.tar.gz#sha256=f4526d078aedd5187d0508aa5f9a01eae6a48a470ed678406da94b4cd6524b7e (from https://pypi.org/simple/psycopg2/). Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.
    ERROR: Command errored out with exit status 1:
     command: /home/emcp/Dev/git/meltano--ib/.meltano/loaders/target-postgres/venv/bin/python -c 'import io, os, sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-wv16bb9e/psycopg2_6754af545b67469c96e33d73ceab26f3/setup.py'"'"'; __file__='"'"'/tmp/pip-install-wv16bb9e/psycopg2_6754af545b67469c96e33d73ceab26f3/setup.py'"'"';f = getattr(tokenize, '"'"'open'"'"', open)(__file__) if os.path.exists(__file__) else io.StringIO('"'"'from setuptools import setup; setup()'"'"');code = f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-pip-egg-info-8m_hqan0
         cwd: /tmp/pip-install-wv16bb9e/psycopg2_6754af545b67469c96e33d73ceab26f3/
    Complete output (23 lines):
    running egg_info
    creating /tmp/pip-pip-egg-info-8m_hqan0/psycopg2.egg-info
    writing /tmp/pip-pip-egg-info-8m_hqan0/psycopg2.egg-info/PKG-INFO
    writing dependency_links to /tmp/pip-pip-egg-info-8m_hqan0/psycopg2.egg-info/dependency_links.txt
    writing top-level names to /tmp/pip-pip-egg-info-8m_hqan0/psycopg2.egg-info/top_level.txt
    writing manifest file '/tmp/pip-pip-egg-info-8m_hqan0/psycopg2.egg-info/SOURCES.txt'
    
    Error: pg_config executable not found.
    
    pg_config is required to build psycopg2 from source.  Please add the directory
    containing pg_config to the $PATH or specify the full executable path with the
    option:
    
        python setup.py build_ext --pg-config /path/to/pg_config build ...
    
    or with the pg_config option in 'setup.cfg'.
    
    If you prefer to avoid building psycopg2 from source, please install the PyPI
    'psycopg2-binary' package instead.
    
    For further information please check the 'doc/src/install.rst' file (also at
    <http://initd.org/psycopg/docs/install.html>).
    
    ----------------------------------------
WARNING: Discarding https://files.pythonhosted.org/packages/94/09/2f1fae36d83e2315b90ee91738d01baf8af8c945726bf4b4708fcec3256d/psycopg2-2.7.6.tar.gz#sha256=4a658550b0bcb259e97f77f2dc93ed6b108fe2eda963a9e6fc8b48040d542ec2 (from https://pypi.org/simple/psycopg2/). Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.
    ERROR: Command errored out with exit status 1:
     command: /home/emcp/Dev/git/meltano--ib/.meltano/loaders/target-postgres/venv/bin/python -c 'import io, os, sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-wv16bb9e/psycopg2-binary_958898d9f482472093f3b321dd306c42/setup.py'"'"'; __file__='"'"'/tmp/pip-install-wv16bb9e/psycopg2-binary_958898d9f482472093f3b321dd306c42/setup.py'"'"';f = getattr(tokenize, '"'"'open'"'"', open)(__file__) if os.path.exists(__file__) else io.StringIO('"'"'from setuptools import setup; setup()'"'"');code = f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-pip-egg-info-oj_f5uex
         cwd: /tmp/pip-install-wv16bb9e/psycopg2-binary_958898d9f482472093f3b321dd306c42/
    Complete output (23 lines):
    running egg_info
    creating /tmp/pip-pip-egg-info-oj_f5uex/psycopg2_binary.egg-info
    writing /tmp/pip-pip-egg-info-oj_f5uex/psycopg2_binary.egg-info/PKG-INFO
    writing dependency_links to /tmp/pip-pip-egg-info-oj_f5uex/psycopg2_binary.egg-info/dependency_links.txt
    writing top-level names to /tmp/pip-pip-egg-info-oj_f5uex/psycopg2_binary.egg-info/top_level.txt
    writing manifest file '/tmp/pip-pip-egg-info-oj_f5uex/psycopg2_binary.egg-info/SOURCES.txt'
    
    Error: pg_config executable not found.
    
    pg_config is required to build psycopg2 from source.  Please add the directory
    containing pg_config to the $PATH or specify the full executable path with the
    option:
    
        python setup.py build_ext --pg-config /path/to/pg_config build ...
    
    or with the pg_config option in 'setup.cfg'.
    
    If you prefer to avoid building psycopg2 from source, please install the PyPI
    'psycopg2-binary' package instead.
    
    For further information please check the 'doc/src/install.rst' file (also at
    <http://initd.org/psycopg/docs/install.html>).
    
    ----------------------------------------
WARNING: Discarding https://files.pythonhosted.org/packages/77/09/4991fcd9a8f4bea1ee3948e1729fa17c184d25bd10809bacc143626361b9/psycopg2-binary-2.7.4.tar.gz#sha256=de4f88f823037a71ea5ef3c1041d96b8a68d73343133edda684fd42f575bd9d7 (from https://pypi.org/simple/psycopg2-binary/). Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.
ERROR: Cannot install singer-target-postgres==0.1.0, singer-target-postgres==0.1.1, singer-target-postgres==0.1.10, singer-target-postgres==0.1.11, singer-target-postgres==0.1.2, singer-target-postgres==0.1.3, singer-target-postgres==0.1.4, singer-target-postgres==0.1.5, singer-target-postgres==0.1.6, singer-target-postgres==0.1.7, singer-target-postgres==0.1.8, singer-target-postgres==0.1.9, singer-target-postgres==0.2.0, singer-target-postgres==0.2.1, singer-target-postgres==0.2.2, singer-target-postgres==0.2.3 and singer-target-postgres==0.2.4 because these package versions have conflicting dependencies.
ERROR: ResolutionImpossible: for help visit https://pip.pypa.io/en/latest/user_guide/#fixing-conflicting-dependencies

Failed to install plugin(s)

EDIT: Found solution was #185 (comment)