It looks like citoid is logging garbage on certain errors in the form of "err_body_<number>: <number>" in its gelf / json logs. Additionally it looks like all HTTP response headers are also logged as key: value, e.g. `err_headers_x-app-status: 1`.
This can cause "fields explosion" problems in elasticsearch/logstash indices. See also T180051 for more context. One fix would be to use sth like `err_response: <whole http response>`, in other words using only one nested key/value pair as opposed to multiple key:value at top level.
```
{
"_index": "logstash-2019.11.12",
"_type": "citoid",
"_id": "AW5fRqjXKWrIH1QREwG7",
"_score": 1,
"_source": {
"err_body_192": 105,
"err_body_191": 97,
"err_body_190": 116,
"err_body_199": 116,
"err_body_198": 104,
"err_body_197": 46,
"err_body_196": 116,
"err_body_195": 110,
"err_body_194": 101,
"err_body_193": 109,
"err_body_29": 70,
"err_body_27": 69,
"err_body_28": 84,
"err_body_25": 47,
"err_body_26": 73,
"err_body_23": 45,
"err_body_24": 47,
"err_body_21": 32,
"err_body_22": 34,
"err_body_20": 67,
"version": "1.0",
"tags": [
"input-gelf-12201",
"deprecated-input",
"es",
"gelf",
"normalized_message_untrimmed"
],
"err_body_18": 76,
"err_headers_content-type": "text/html; charset=iso-8859-1",
"err_body_19": 73,
"err_body_16": 85,
"err_body_17": 66,
"err_body_14": 32,
"err_body_15": 80,
"err_body_12": 77,
"err_body_13": 76,
"err_body_10": 72,
"err_body_11": 84,
"err_body_2": 68,
"err_body_50": 10,
"err_body_1": 33,
"err_body_51": 60,
"err_body_0": 60,
"err_levelPath": "warn/scraper",
"err_body_49": 62,
"err_body_47": 78,
"err_body_9": 32,
"err_body_48": 34,
"err_body_8": 69,
"err_body_45": 47,
"err_body_7": 80,
"err_body_46": 69,
"err_body_6": 89,
"err_body_43": 48,
"err_body_5": 84,
"err_body_44": 47,
"err_body_4": 67,
"err_body_41": 50,
"err_body_3": 79,
"err_body_42": 46,
"err_body_40": 32,
"err_body_38": 77,
"err_body_39": 76,
"err_body_36": 72,
"err_body_37": 84,
"err_body_34": 68,
"err_body_35": 32,
"err_body_32": 68,
"err_body_33": 84,
"err_body_30": 47,
"err_body_31": 47,
"err_body_72": 48,
"err_body_73": 52,
"err_body_70": 62,
"err_body_71": 52,
"err_body_156": 112,
"err_body_155": 115,
"err_body_154": 47,
"err_body_153": 115,
"err_body_152": 112,
"err_body_151": 117,
"err_body_150": 111,
"err_body_159": 110,
"err_body_158": 110,
"err_body_157": 105,
"err_body_69": 101,
"err_body_67": 116,
"err_body_68": 108,
"err_body_65": 116,
"err_body_66": 105,
"err_body_63": 10,
"err_body_64": 60,
"err_body_61": 100,
"err_body_62": 62,
"err_body_60": 97,
"err_body_167": 99,
"err_body_166": 114,
"err_body_165": 97,
"err_body_164": 47,
"err_body_163": 114,
"err_body_162": 101,
"normalized_message": "404",
"err_body_161": 107,
"err_body_160": 97,
"err_body_169": 105,
"err_body_168": 104,
"err_body_58": 104,
"err_body_59": 101,
"err_body_56": 62,
"err_body_57": 60,
"err_body_54": 109,
"err_body_55": 108,
"err_body_52": 104,
"err_body_53": 116,
"err_body_94": 47,
"err_body_170": 118,
"err_body_95": 104,
"err_body_92": 10,
"err_body_93": 60,
"err_body_90": 101,
"err_body_91": 62,
"err_body_178": 47,
"err_body_177": 52,
"err_body_176": 48,
"err_body_175": 48,
"err_body_174": 50,
"err_body_173": 47,
"err_body_172": 115,
"err_body_171": 101,
"err_body_179": 48,
"gelf_level": "4",
"err_body_89": 108,
"err_headers_cache-control": "private",
"err_body_87": 105,
"err_body_88": 116,
"err_body_85": 47,
"err_body_86": 116,
"err_body_83": 100,
"err_body_181": 45,
"err_body_84": 60,
"err_body_180": 52,
"err_body_81": 117,
"err_body_82": 110,
"err_body_80": 111,
"err_body_189": 114,
"err_body_188": 101,
"err_body_187": 116,
"err_body_186": 110,
"message": "404",
"err_body_185": 101,
"err_body_184": 47,
"err_body_183": 52,
"err_body_182": 49,
"err_body_78": 32,
"err_body_79": 70,
"err_body_76": 111,
"err_body_77": 116,
"err_body_74": 32,
"err_body_75": 78,
"err_body_112": 111,
"err_body_233": 47,
"err_body_111": 78,
"err_body_232": 60,
"err_body_110": 62,
"err_body_231": 46,
"err_body_230": 114,
"type": "citoid",
"err_body_119": 100,
"err_body_118": 110,
"err_body_239": 98,
"err_body_117": 117,
"err_body_238": 47,
"err_body_116": 111,
"err_body_237": 60,
"err_body_115": 70,
"err_body_236": 10,
"err_body_114": 32,
"err_body_235": 62,
"err_body_113": 116,
"err_body_234": 112,
"err_headers_server": "Apache",
"err_body_123": 49,
"err_body_244": 60,
"err_body_122": 104,
"err_body_243": 62,
"err_body_121": 47,
"err_body_242": 121,
"err_body_120": 60,
"err_body_241": 100,
"err_body_240": 111,
"err_body_129": 84,
"err_body_128": 62,
"err_body_249": 108,
"err_body_127": 112,
"err_body_248": 109,
"err_body_126": 60,
"err_body_247": 116,
"err_body_125": 10,
"err_body_246": 104,
"err_body_124": 62,
"err_body_245": 47,
"err_body_98": 100,
"err_body_99": 62,
"err_body_96": 101,
"err_body_97": 97,
"err_body_134": 101,
"err_body_133": 114,
"err_body_132": 32,
"err_body_131": 101,
"err_body_130": 104,
"err_body_251": 10,
"err_body_250": 62,
"file": "/srv/service/node_modules/preq/index.js",
"err_body_139": 116,
"err_body_138": 115,
"err_body_137": 101,
"err_body_136": 117,
"err_body_135": 113,
"err_stack": "HTTPError: 404\n at request.then (/srv/service/node_modules/preq/index.js:212:23)\n at tryCatcher (/srv/service/node_modules/bluebird/js/release/util.js:16:23)\n at Promise._settlePromiseFromHandler (/srv/service/node_modules/bluebird/js/release/promise.js:517:31)\n at Promise._settlePromise (/srv/service/node_modules/bluebird/js/release/promise.js:574:18)\n at Promise._settlePromise0 (/srv/service/node_modules/bluebird/js/release/promise.js:619:10)\n at Promise._settlePromises (/srv/service/node_modules/bluebird/js/release/promise.js:699:18)\n at _drainQueueStep (/srv/service/node_modules/bluebird/js/release/async.js:138:12)\n at _drainQueue (/srv/service/node_modules/bluebird/js/release/async.js:131:9)\n at Async._drainQueues (/srv/service/node_modules/bluebird/js/release/async.js:147:5)\n at Immediate.Async.drainQueues (/srv/service/node_modules/bluebird/js/release/async.js:17:14)\n at runCallback (timers.js:672:20)\n at tryOnImmediate (timers.js:645:5)\n at processImmediate [as _immediateCallback] (timers.js:617:5)",
"err_body_145": 76,
"err_body_144": 82,
"err_body_143": 85,
"err_body_142": 32,
"err_body_141": 100,
"err_body_140": 101,
"@timestamp": "2019-11-12T11:01:36.448Z",
"err_body_149": 114,
"err_body_148": 103,
"err_name": "citoid",
"err_body_147": 47,
"err_body_146": 32,
"pid": 27,
"host": "citoid-production-699db9c4-4bbsx",
"source_host": "10.64.65.0",
"level": "WARNING",
"err_body_200": 109,
"err_body_208": 111,
"err_body_207": 110,
"err_body_206": 32,
"err_body_205": 115,
"err_body_204": 97,
"err_body_203": 119,
"err_body_202": 32,
"err_body_201": 108,
"err_body_209": 116,
"line": "212",
"err_body_211": 102,
"err_body_210": 32,
"err_message": "404",
"err_body_219": 32,
"err_body_218": 110,
"err_body_217": 111,
"err_body_216": 32,
"err_body_215": 100,
"err_body_214": 110,
"err_body_213": 117,
"err_body_212": 111,
"@version": "1",
"err_headers_cteonnt-length": "252",
"err_body_101": 98,
"err_body_222": 105,
"err_headers_connection": "close",
"err_body_100": 60,
"err_body_221": 104,
"err_body_220": 116,
"err_body_109": 49,
"err_body_108": 104,
"err_body_229": 101,
"err_body_107": 60,
"err_body_228": 118,
"err_body_106": 10,
"err_body_227": 114,
"err_body_105": 62,
"err_body_226": 101,
"err_body_104": 121,
"err_body_225": 115,
"err_body_103": 100,
"err_body_224": 32,
"err_body_102": 111,
"err_body_223": 115,
"err_status": 404,
"err_headers_date": "Tue, 12 Nov 2019 11:01:36 GMT"
},
"fields": {
"@timestamp": [
1573556496448
]
}
}
```