Failed to load zones or crashes on queries

[SivaKesava1]

Hi,

I built erldns using make and then added the following file as erldns.config.

[
  {erldns,[
      {servers, [
        [{name, inet_localhost_1}, {address, "127.0.0.1"}, {port, 53}, {family, inet}]
      ]},

      {use_root_hints, false},
      {catch_exceptions, false},
      {zones, "priv/campus.json"}
    ]},
  {lager, [
      {error_logger_redirect, false}
    ]}
].

I have placed the following campus.json file in priv directory.

[
  {
    "name": "campus.edu",
    "records": [
      {
        "name": "campus.edu",
        "type": "SOA",
        "ttl": 3600,
        "data": {
          "mname": "ns1.campus.edu",
          "rname": "root.campus.edu",
          "serial": 3,
          "refresh": 86400,
          "retry": 7200,
          "expire": 604800,
          "minimum": 300
        }
      },
      {
        "name": "campus.edu",
        "type": "NS",
        "ttl": "500",
        "data": {
          "dname": "ns1.outside.edu"
        }
      },
      {
        "name": "*.e.campus.edu",
        "type": "A",
        "ttl": "500",
        "data": {
          "ip": "1.1.1.1"
        }
      },
      {
        "name": "t.e.campus.edu",
        "type": "A",
        "ttl": "500",
        "data": {
          "ip": "2.2.2.2"
        }
      }
    ]
  }
]

Then I ran ./rebar3 release . Though there were some out of date warnings, it successfully assembled it. Then I ran ./_build/default/rel/erldns/bin/erldns foreground which gave the error Failed to load zones (module: erldns_zone_loader, event: read_file_error, reason: enoent). Whatever I did and wherever I placed the file, it gave the same error. I finally tried naming the file as example.zone.json, and it successfully loaded it!! I am not sure what the problem here is, and any help would be useful.

The logs while loading the file were:

09:33:01.061 [info] Loaded zones (count: 1)
09:33:01.061 [info] Notifying servers to start
09:33:01.061 [info] Starting the UDP and TCP supervisor
09:33:01.061 [info] Starting UDP server (family: inet, address: {127,0,0,1}, port: 53)
09:33:01.061 [info] UDP server (family: inet, address: {127,0,0,1}, socket: #Port<0.10>)
09:33:01.062 [info] Starting TCP server for inet on address {127,0,0,1} port 53

Then I queried it using dig @127.0.0.1 +norecurse t.e.campus.edu, which resulted in a huge crash report message. Some parts of that message are:

=ERROR REPORT==== 5-Nov-2020::09:35:40.091530 ===
** Generic server <0.771.0> terminating
** Last message in was {process,
                           {dns_message,46922,false,0,false,false,true,false,
                               ....
** When Server state == {state}
** Reason for termination ==
** {badarg,
       [{dns,encode_message_rec,3,
           ....

=CRASH REPORT==== 5-Nov-2020::09:35:40.092258 ===
  crasher:
    initial call: erldns_worker_process:init/1
    pid: <0.771.0>
    registered_name: []
    exception error: bad argument
      in function  dns:encode_message_rec/3 (/erldns/_build/default/lib/dns_erlang/src/dns.erl, line 590)
      in call from dns:encode_message_rec_list/5 (/erldns/_build/default/lib/dns_erlang/src/dns.erl, line 557)
      in call from dns:encode_message_d_req/5 (/erldns/_build/default/lib/dns_erlang/src/dns.erl, line 423)
      in call from dns:encode_message_def

09:35:50.093 [error] Error handling UDP query (module: erldns_worker, event: handle_udp_query_error, error: {error,{exit,{{badarg,.....
{dns_message,46922,false,0,false,false,true,false,true,false,0,1,0,0,1,[{dns_query,<<"t.e.campus.edu">>,1,1}],[],[],..

System:
OS: Ubuntu bionic (actually a docker image)
Erlang installed using the steps mentioned here as the apt install erlang gave errors for the make.

I am not used to Erlang, so I did not try much to find the root cause. Thanks for any help in advance

[san983]

Hi @SivaKesava1, I'm showing that the JSON you've pasted specifies the TTLs as strings ("500") not integers. I was able to reproduce the error, and also to successfully load/query the zone switching the TTL to integers

[SivaKesava1]

Thanks, @san983 for the reply. I, now run into JSON issues with the release command. I have the following Dockerfile to run ErlDNS:

FROM ubuntu:jammy

RUN apt-get update 
RUN apt-get -y upgrade 
RUN apt-get install -y \
    make \
    curl \
    erlang \
    git \
    gnupg \
    python3 \
    rebar3 \
    vim \
    wget \
    dnsutils 
 
ENV TZ=US/Pacific
RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone

RUN git clone https://github.com/dnsimple/erldns.git
RUN cd erldns && \
    make

COPY Erldns/erldns.config erldns/
RUN cd erldns && rebar3 release

# Run eternal loop
CMD ["/bin/bash", "-c", "while :; do sleep 10; done"]

where I have also added the above erldns.config and the fixed JSON.

When I run rebar3 release now, I get JSON errors:

===> Assembling release erldns-3.0.0...
===> There are missing function calls in the release.
===> Make sure all applications needed at runtime are included in the release.
===> erldns_storage:load_zones/1 calls undefined function json:decode/3
===> erldns_zone_encoder:json_encode_kw_list/1 calls undefined function json:encode/2
===> erldns_zone_encoder:json_encode_term/2 calls undefined function json:encode_key_value_list/2
===> erldns_zone_encoder:json_encode_term/2 calls undefined function json:encode_value/2
===> erldns_zone_loader:load_zones/0 calls undefined function json:decode/3

I saw that this commit 08f1a8a#diff-427d8ddce21ccc4fae24fb547c7a82c2a793ed57208d8343e519e0aec8119ff7 updated to the default JSON module. However, I am still seeing issues on Ubuntu:Jammy.

[san983]

@SivaKesava1 I'm showing that your Dockerfile actually installs erlang v24.x which is EOL already. The current version of main actually works on erlang 27+

root@c14a951b1dd4:/erldns# apt-cache policy erlang
erlang:
  Installed: 1:24.2.1+dfsg-1ubuntu0.1
  Candidate: 1:24.2.1+dfsg-1ubuntu0.1
  Version table:
 *** 1:24.2.1+dfsg-1ubuntu0.1 500
        500 http://ports.ubuntu.com/ubuntu-ports jammy-updates/universe arm64 Packages
        500 http://ports.ubuntu.com/ubuntu-ports jammy-security/universe arm64 Packages
        100 /var/lib/dpkg/status
     1:24.2.1+dfsg-1 500
        500 http://ports.ubuntu.com/ubuntu-ports jammy/universe arm64 Packages