Fix friendbot 500 errors

[tomquisel]

Occasionally, friendbot responds with 500 errors. Some were fixed by #1511, but there are others that @accordeiro identified below. Let's fix those.

[accordeiro]

It seems like fixing #1511 got rid of most errors, but I've found two others that are still relatively frequent:

Error 1: invalid URL escape

It seems like providing an invalid URL causes a 500:

Example 1.1

Request

time=“2019-07-30T08:19:47.697Z” level=info msg=“finished request” bytes=444 duration=“53.107µs” method=GET path=“/?addr=%s” pid=15931 req=frontend-friendbot-001a/HlNPxBapp5-053399 status=500 subsys=http

Response

time=“2019-07-30T08:19:47.697Z” level=error msg=“invalid URL escape \”%s\”” pid=15931 stack=unknown

Error 2: result_xdr not populated

This will probably require some deeper digging.

Example 2.1

Request

time="2019-07-30T10:38:59.343Z" level=info msg="finished request" bytes=444 duration=30.690100736s method=GET path="/?addr=GCLO3KDICPIBYCDOZGBJYBVGKRD2L2G5DENJFJFBRD5BJOK24X5LD42M" pid=15931 req=frontend-friendbot-001a/HlNPxBapp5-054563 status=500 subsys=http

Response

time=“2019-07-30T10:38:59.343Z” level=error msg=“submitting tx to minion: submitting tx to horizon: error getting horizon error code: result_xdr not populated” pid=15931 stack=“[main.go:43 minion.go:52 asm_amd64.s:1333]”

Example 2.2

Request

time=“2019-07-30T05:18:50.886Z” level=info msg=“finished request” bytes=444 duration=30.404681807s method=GET path=“/?addr=GBHFUQUN5BGKU7G5I2FAFHLMR3VXXYFGMEZHWU2UJE4E2CHZOD7DMILN” pid=15931 req=frontend-friendbot-001a/HlNPxBapp5-051987 status=500 subsys=http

Response

time=“2019-07-30T05:18:50.886Z” level=error msg=“submitting tx to minion: submitting tx to horizon: error getting horizon error code: result_xdr not populated” pid=15931 stack=“[main.go:43 minion.go:52 asm_amd64.s:1333]”

[accordeiro]

@tomquisel I've created a PR (#1612) to address Error 1.

Error 2 seems trickier to reproduce since it seems to be an error between Friendbot <> Horizon, rather than between Client <> Friendbot – but I'll keep investigating.

[leighmcculloch]

Error 2 isn't occurring for me now in both examples above. Given this was related to Friendbot => Horizon is it possible something changed in Horizon that subsequently fixed these cases?

$ curl 'https://friendbot.stellar.org/?addr=GCLO3KDICPIBYCDOZGBJYBVGKRD2L2G5DENJFJFBRD5BJOK24X5LD42M'
{
  "_links": {
    "transaction": {
      "href": "https://horizon-testnet.stellar.org/transactions/59741f42e2d5fd92bf9b9367fe85751e6761699e509b0461cc510f50966f9099"
    }
  },
  "hash": "59741f42e2d5fd92bf9b9367fe85751e6761699e509b0461cc510f50966f9099",
  "ledger": 860917,
  "envelope_xdr": "AAAAAMBaBqzOwbbQH5aFMkY7zPrIMj6IA88VmwPzp4JllbxBAAGGoAAHBfUAAAC6AAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAQAAAAEAAAAAEH3Rayw4M0iCLoEe96rPFNGYim8AVHJU0z4ebYZW4JwAAAAAAAAAAJbtqGgT0BwIbsmCnAamVEel6N0ZGpKkoYj6FLla5fqxAAAAF0h26AAAAAAAAAAAAmWVvEEAAABAuqnfhgJftmx6ckJubkvnFqG9vhjRHTfzlxMwHkkvoQI9nlmUEv42aabL/4FJRsmULHT6eNX5zHdZZO/dnmOfBoZW4JwAAABARMrKYdQfoHbeLzHChyn1H9Tae8Ynq9Dwfz5gazNxH9M6wwMzCcSD7Uq0LON2EPTuyjdZKkC5XG9LRFQYthe1BQ==",
  "result_xdr": "AAAAAAAAAGQAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAA=",
  "result_meta_xdr": "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"
}%

$ curl 'https://friendbot.stellar.org/?addr=GBHFUQUN5BGKU7G5I2FAFHLMR3VXXYFGMEZHWU2UJE4E2CHZOD7DMILN' 
{
  "_links": {
    "transaction": {
      "href": "https://horizon-testnet.stellar.org/transactions/8dafa8b6d86d94deb7a0d89e3dc57bda31bacb99bb4a1e2fec18d34b5528c1ce"
    }
  },
  "hash": "8dafa8b6d86d94deb7a0d89e3dc57bda31bacb99bb4a1e2fec18d34b5528c1ce",
  "ledger": 860927,
  "envelope_xdr": "AAAAAPlCtJAvCuJZf+v2596U31MClKJtWWqv7e3JJ8D/kwf6AAGGoAAHBfUAAAC6AAAAAQAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAQAAAAEAAAAAEH3Rayw4M0iCLoEe96rPFNGYim8AVHJU0z4ebYZW4JwAAAAAAAAAAE5aQo3oTKp83UaKAp1sjut74KZhMntTVEk4TQj5cP42AAAAF0h26AAAAAAAAAAAAv+TB/oAAABA6PT0W2/SBuJ7EyTq6CVTLuay9i0IhZZZen2nuPQck5QuUrYd5kU/pRqKshESqvdDBiuDEC1tTPQfjltlTdKmAYZW4JwAAABAEA+pddQRmPEXr89uHLf5PvgqciKKKS0dFaYOi4HSWC28kXWv/wIYrwKwOJwBXwlQvsz8WgZ3wql3BnCU/5I1Dg==",
  "result_xdr": "AAAAAAAAAGQAAAAAAAAAAQAAAAAAAAAAAAAAAAAAAAA=",
  "result_meta_xdr": "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"
}%