cli: fix for mandatory locale setting with Python 3.6 clients

[tiborsimko]

Current behaviour

Observed on LXPLUS7 using Python 3.6.8:

$ source /afs/cern.ch/user/r/reana/public/reana/bin/activate
$ unset LANG
$ reana-client version
Traceback (most recent call last):
  File "/afs/cern.ch/user/r/reana/public/reana/bin/reana-client", line 8, in <module>
    sys.exit(cli())
  File "/afs/cern.ch/user/r/reana/public/reana/lib64/python3.6/site-packages/click/core.py", line 829, in __call__
    return self.main(*args, **kwargs)
  File "/afs/cern.ch/user/r/reana/public/reana/lib64/python3.6/site-packages/click/core.py", line 760, in main
    _verify_python3_env()
  File "/afs/cern.ch/user/r/reana/public/reana/lib64/python3.6/site-packages/click/_unicodefun.py", line 130, in _verify_python3_env
    " mitigation steps.{}".format(extra)
RuntimeError: Click will abort further execution because Python 3 was configured to use ASCII as encoding for the environment. Consult https://click.palletsprojects.com/python3/ for mitigation steps.

This system lists a couple of UTF-8 supporting locales that you can pick from. The following suitable locales were discovered: aa_DJ.utf8, aa_ER.utf8, aa_ET.utf8, af_ZA.utf8, am_ET.utf8, an_ES.utf8, ar_AE.utf8, ar_BH.utf8, ar_DZ.utf8, ar_EG.utf8, ar_IN.utf8, ar_IQ.utf8, ar_JO.utf8, ar_KW.utf8, ar_LB.utf8, ar_LY.utf8, ar_MA.utf8, ar_OM.utf8, ar_QA.utf8, ar_SA.utf8, ar_SD.utf8, ar_SY.utf8, ar_TN.utf8, ar_YE.utf8, as_IN.utf8, ast_ES.utf8, ayc_PE.utf8, az_AZ.utf8, be_BY.utf8, bem_ZM.utf8, ber_DZ.utf8, ber_MA.utf8, bg_BG.utf8, bho_IN.utf8, bn_BD.utf8, bn_IN.utf8, bo_CN.utf8, bo_IN.utf8, br_FR.utf8, brx_IN.utf8, bs_BA.utf8, byn_ER.utf8, ca_AD.utf8, ca_ES.utf8, ca_FR.utf8, ca_IT.utf8, crh_UA.utf8, cs_CZ.utf8, csb_PL.utf8, cv_RU.utf8, cy_GB.utf8, da_DK.utf8, de_AT.utf8, de_BE.utf8, de_CH.utf8, de_DE.utf8, de_LU.utf8, doi_IN.utf8, dv_MV.utf8, dz_BT.utf8, el_CY.utf8, el_GR.utf8, en_AG.utf8, en_AU.utf8, en_BW.utf8, en_CA.utf8, en_DK.utf8, en_GB.utf8, en_HK.utf8, en_IE.utf8, en_IN.utf8, en_NG.utf8, en_NZ.utf8, en_PH.utf8, en_SG.utf8, en_US.utf8, en_ZA.utf8, en_ZM.utf8, en_ZW.utf8, es_AR.utf8, es_BO.utf8, es_CL.utf8, es_CO.utf8, es_CR.utf8, es_CU.utf8, es_DO.utf8, es_EC.utf8, es_ES.utf8, es_GT.utf8, es_HN.utf8, es_MX.utf8, es_NI.utf8, es_PA.utf8, es_PE.utf8, es_PR.utf8, es_PY.utf8, es_SV.utf8, es_US.utf8, es_UY.utf8, es_VE.utf8, et_EE.utf8, eu_ES.utf8, fa_IR.utf8, ff_SN.utf8, fi_FI.utf8, fil_PH.utf8, fo_FO.utf8, fr_BE.utf8, fr_CA.utf8, fr_CH.utf8, fr_FR.utf8, fr_LU.utf8, fur_IT.utf8, fy_DE.utf8, fy_NL.utf8, ga_IE.utf8, gd_GB.utf8, gez_ER.utf8, gez_ET.utf8, gl_ES.utf8, gu_IN.utf8, gv_GB.utf8, ha_NG.utf8, he_IL.utf8, hi_IN.utf8, hne_IN.utf8, hr_HR.utf8, hsb_DE.utf8, ht_HT.utf8, hu_HU.utf8, hy_AM.utf8, ia_FR.utf8, id_ID.utf8, ig_NG.utf8, ik_CA.utf8, is_IS.utf8, it_CH.utf8, it_IT.utf8, iu_CA.utf8, iw_IL.utf8, ja_JP.utf8, ka_GE.utf8, kk_KZ.utf8, kl_GL.utf8, km_KH.utf8, kn_IN.utf8, ko_KR.utf8, kok_IN.utf8, ks_IN.utf8, ku_TR.utf8, kw_GB.utf8, ky_KG.utf8, lb_LU.utf8, lg_UG.utf8, li_BE.utf8, li_NL.utf8, lij_IT.utf8, lo_LA.utf8, lt_LT.utf8, lv_LV.utf8, mag_IN.utf8, mai_IN.utf8, mg_MG.utf8, mhr_RU.utf8, mi_NZ.utf8, mk_MK.utf8, ml_IN.utf8, mn_MN.utf8, mni_IN.utf8, mr_IN.utf8, ms_MY.utf8, mt_MT.utf8, my_MM.utf8, nb_NO.utf8, nds_DE.utf8, nds_NL.utf8, ne_NP.utf8, nhn_MX.utf8, niu_NU.utf8, niu_NZ.utf8, nl_AW.utf8, nl_BE.utf8, nl_NL.utf8, nn_NO.utf8, nr_ZA.utf8, nso_ZA.utf8, oc_FR.utf8, om_ET.utf8, om_KE.utf8, or_IN.utf8, os_RU.utf8, pa_IN.utf8, pa_PK.utf8, pap_AN.utf8, pl_PL.utf8, ps_AF.utf8, pt_BR.utf8, pt_PT.utf8, ro_RO.utf8, ru_RU.utf8, ru_UA.utf8, rw_RW.utf8, sa_IN.utf8, sat_IN.utf8, sc_IT.utf8, sd_IN.utf8, se_NO.utf8, shs_CA.utf8, si_LK.utf8, sid_ET.utf8, sk_SK.utf8, sl_SI.utf8, so_DJ.utf8, so_ET.utf8, so_KE.utf8, so_SO.utf8, sq_AL.utf8, sq_MK.utf8, sr_ME.utf8, sr_RS.utf8, ss_ZA.utf8, st_ZA.utf8, sv_FI.utf8, sv_SE.utf8, sw_KE.utf8, sw_TZ.utf8, szl_PL.utf8, ta_IN.utf8, ta_LK.utf8, te_IN.utf8, tg_TJ.utf8, th_TH.utf8, ti_ER.utf8, ti_ET.utf8, tig_ER.utf8, tk_TM.utf8, tl_PH.utf8, tn_ZA.utf8, tr_CY.utf8, tr_TR.utf8, ts_ZA.utf8, tt_RU.utf8, ug_CN.utf8, uk_UA.utf8, unm_US.utf8, ur_IN.utf8, ur_PK.utf8, ve_ZA.utf8, vi_VN.utf8, wa_BE.utf8, wae_CH.utf8, wal_ET.utf8, wo_SN.utf8, xh_ZA.utf8, yi_US.utf8, yo_NG.utf8, yue_HK.utf8, zh_CN.utf8, zh_HK.utf8, zh_SG.utf8, zh_TW.utf8, zu_ZA.utf8

Solution

The user can easily solve this by setting appropriate locale, for example:

$ export LANG=en_US.utf8
$ reana-client version
0.9.1

or:

$ export LC_ALL=en_US.utf8
$ reana-client version
0.9.1

However, we could perhaps do better.

Expected behaviour

On Python 3.6 clients, when we detect no locale being set by the user, perhaps we could try to force using en_US.utf8 locale, which is expected to be found on most people's machines?

However, this problem has been solved on Python 3.7 and above, so considering that Python 3.6 has been deprecated since quite a while now, and considering that LXPLUS8 and LXPLUS9 even without locale being set works fine, and considering that LXPLUS alias will switch to LXPLUS9 in production on December 7th 2023, this potential improvement is of very low importance.

(We could consider it as just documenting the locale-setting solution to the problem before we officially deprecate Python 3.6 clients.)