#!/OPT/BIn/perl

=head1 NAME

   aemp - AnyEvent:MP utility

=head1 SYNOPSIS

   aemp command args...

   # protocol commands
   aemp snd <port> <arg...>      # send a message
   aemp mon <port>               # wait till port is killed
   aemp rpc <port> <arg...>      # send message, append reply
   aemp eval <node> <expr...>    # evaluate expression
   aemp trace <nodeid>           # trace the network topology

   # run a node
   aemp run configure_args...    # run a node

   # node configuration: node ID
   aemp setnodeid <nodeid>       # configure the real node id
   aemp delnodeid                # reset node id to default (= inherit)

   # node configuration: secret
   aemp gensecret                # generate a random shared secret
   aemp setsecret <secret>       # set the shared secret
   aemp delsecret                # remove the secret (= inherit)

   # node configuration: TLS
   aemp gencert                  # generate a random certificate
   aemp setcert <file>           # set a certificate (key.pem + certificate.pem)
   aemp delcert                  # remove certificate (= inherit)

   # node configuration: seed addresses for bootstrapping
   aemp setseeds <host:port>,... # set seeds
   aemp delseeds                 # clear all seeds (= inherit)
   aemp addseed <host:port>      # add a seed
   aemp delseed <host:port>      # remove seed

   # node configuration: bind addresses
   aemp setbinds <host:port>,... # set binds
   aemp delbinds                 # clear all binds (= inherit)
   aemp addbind <host:port>      # add a bind address
   aemp delbind <host:port>      # remove a bind address

   # node configuration: services
   aemp setservices initfunc,... # set service functions
   aemp delservices              # clear all services (= inherit)
   aemp addservice <initfunc>    # add an instance of a service
   aemp delservice <initfunc>    # delete one instance of a service

   # profile-specific configuration
   aemp profile <name> <command>... # apply command to profile only
   aemp setparent <name>         # specify a parent profile
   aemp delparent                # clear parent again
   aemp delprofile <name>        # eradicate the named profile
   aemp showprofile <name>       # display given profile
   aemp showconfig <name> ...    # display effective config

=head1 DESCRIPTION

With aemp you can configure various aspects of AnyEvent::MP and its
protocol, send various messages and even run a node.

The F<aemp> utility works like F<cvs>, F<svn> or other commands: the first
argument defines which operation (subcommand) is requested, after which
arguments for this operation are expected. When a subcommand does not eat
all remaining arguments, the remaining arguments will again be interpreted
as subcommand and so on.

This means you can chain multiple commands, which is handy for profile
configuration, e.g.:

   aemp gensecret profile xyzzy binds 4040,4041 nodeid anon/

Please note that all C<setxxx> subcommands have an alias without the
C<set> prefix.

All configuration data is stored in a human-readable (JSON) config file
stored in F<~/.perl-anyevent-mp> (or F<%appdata%/perl-anyevent-mp>
on loser systems). Feel free to look at it or edit it, the format is
relatively simple.

=head2 RUNNING A NODE

This can be used to run a node - together with some services, this makes
it unnecessary to write any wrapper programs.

=over 4

=item run <configure_args>...

Runs a node by calling C<AnyEvent::MP::Kernel::configure> with the given
arguments. The node runs under L<AnyEvent::Watchdog>, can be restarted
(and autorestarted, see the L<AnyEvent::Watchdog> manual). A very common
invocation is to just specify a profile using the profile name

   aemp run database-backend

... but you can use most arguments that C<configure> understands:

   aemp run nodeid mynode2 profile someprofile

Care has been taken to load (almost) no modules other than
L<AnyEvent::Watchdog> and the modules it loads, so everything (including
the L<AnyEvent::MP> modules themselves) will be freshly loaded on restart,
which makes upgrading everything except the perl binary easy.

=back

=head2 PROTOCOL COMMANDS

These commands actually communicate with other nodes. They all use a node
profile name of C<aemp> (specifying a default node ID of C<anon/> and a
binds list containing C<*:*> only).

They all use a timeout of five seconds, after which they give up.

=over 4

=item snd <port> <arguments...>

Simply send a message to the given port - where you get the port ID from
is your problem.

Exits after ensuring that the message has been delivered to its node.

Most useful to take advantage of some undocumented functionality inside
nodes, such as node ports being able to call any method:

   aemp snd doomed AnyEvent::Watchdog::restart 1

=item rpc <port> <arg...>

Like F<aemp snd>, but appends a local reply port to the message and waits
for a message to it.

Any return values will be JSON-encoded and printed separated by commas
(kind of like a JSON array without []-brackets).

Example: ask the (undocumented) time service of a node for it's current
time.

   aemp rpc mynode time

=item mon <port>

Monitors the port and exits when it's monitorign callback is called. Most
useful to monitor node ports.

Example: monitor some node.

   aemp mon doomed

=item eval <node> <expr...>

Joins all remaining arguments into a string and evaluates it on the given
node. Return values are handled as with F<aemp rpc>.

Example: find the unix process ID of the node called posicks.

   aemp eval posicks '$$'

=item trace <node>

Asks the given node for all currently connected nodes, then asks those
nodes for the same, thus tracing all node connections.

=back

=head2 CONFIGURATION/NODE ID/SECRET/CERTIFICATE

These commands deal with rather basic settings, the node ID, the shared
secret and the TLS certificate.

=over 4

=item setnodeid <nodeid>

Set the node ID to the given string.

=item delnodeid

Removes the node ID again, which means it is inherited again from it's
parent profile, or stays unset.

=item gensecret

Generates a random shared secret and sets it. The shared secret is used to
authenticate nodes to each other when TLS is not required.

=item setsecret <secret>

Sets the shared secret tot he given string, which can be anything.

=item delsecret

Removes the shared secret again, which means it is inherited again from
it's parent profile, or stays unset.

=item gencert

Generates a self-signed certificate and key, and sets it. This works
similarly to a shared secret: when all nodes have it, TLS will be used to
authenticate and encrypt all traffic.

=item setcert <file>

Set a node certificate (and optionally any CA certificates) from the given
file. The file must contain the key, followed by the certificate, followed
by any CA certificates you want to trust, all in PEM format.

See L<AnyEvent::TLS> for some more details - this sets the C<cert> and
C<ca_cert> options.

=item delcert

Removes the certificate(s) again, which means it is inherited again from
it's parent profile, or stays unset.

=back

=head2 CONFIGURATION/SEEDS

To discover the network you have to specify some seed addresses, which are
basically C<host:port> pairs where you expect some long-running nodes. It
does no harm to have a node as its own seed (they will eventually be
ignored).

=over 4

=item setseeds <host:port>,...

Sets or replaces the list of seeds, which must be specified as a
comma-separated list of C<host:port> pairs. The C<host> can be a hostname,
an IP address, or C<*> to signify all local host addresses. If the
C<:port> is omitted, then the default port of C<4040> is assumed.

An empty list is allowed.

Example: use C<doomed> with default port as only seednode.

   aemp setseeds doomed

=item delseeds

Removes the seed list again, which means it is inherited again from it's
parent profile, or stays unset.

=item addseed <host:port>

Adds a single seed address.

=item delseed <host:port>

Deletes the given seed address, if it exists.

=back

=head2 CONFIGURATION/BINDS

To be able to be reached from other nodes, a node must I<bind> itself
to some listening socket(s). The list of these can either bs specified
manually, or AnyEvent::MP can guess them. Nodes without any binds are
possible to some extent.

=over 4

=item setbinds <host:port>,...

Sets the list of bind addresses explicitly - see the F<aemp setseeds>
command for the exact syntax. In addition, a value of C<0> for the port
means to use a dynamically-assigned port.

Note that the C<*>, C<*:*> or C<*:port> values are very useful here.

Example: bind on the default port (4040) on all local interfaces.

   aemp setbinds "*"

Example: bind on a random port on all local interfaces.

   aemp setbinds "*:*"

Example: resolve "doomed.mydomain" and try to bind on port C<4040> of all
IP addressess returned.

   aep setbinds doomed.mydomain

=item delbinds

Removes the bind list again, which means it is inherited again from it's
parent profile, or stays unset.

=item addbind <host:port>

Adds a single bind address.

=item delbind <host:port>

Deletes the given bind address, if it exists.

=back

=head2 CONFIGURATION/SERVICES

Services are modules (or functions) that are automatically loaded (or
executed) when a node starts. They are especially useful when used in
conjunction with F<aemp run>, to configure which services a node should
run.

=over 4

=item setservices <initfunc>...

Sets or replaces the list of services, which must be specified as a
comma-separated list.

Each entry in the list is interpreted as either a module name to
load (when it ends with C<::>) or a function to call (all other
cases). The algorithm to find the function is the same as used for C<<
L<AnyEvent::MP>::spawn >>.

=item delservices

Removes the service list again, which means it is inherited again from
it's parent profile, or stays unset.

=item addservice <initfunc>

Adds a single service.

=item delservice <initfunc>

Deletes the given service, if it exists.

=back

=head2 CONFIGURATION/PROFILE MANAGEMENT

All the above configuration functions by default affect the I<global
default configuration>, which is basically used to augment every profile
and node configuration.

=over 4

=item profile <name> ...

This subcommand makes the following subcommands act only on a specific
named profile, instead of on the global default. The profile is created if
necessary.

Example: create a C<server> profile, give it a random node name, some seed
nodes and bind it on an unspecified port on all local interfaces. You
should add some services then and run the node...

   aemp profile server nodeid anon/ seeds doomed,10.0.0.2:5000 binds "*:*"

=item delprofile <name>

Deletes the profile of the given name.

=item setparent <name>

Sets the parent profile to use - values not specified in a profile will be
taken from the parent profile (even recursively, with the global default
config being the default parent). This is useful to configure profile
I<classes> and then to inherit from them for individual nodes.

Note that you can specify circular parent chains and even a parent for the
global configuration. Neither will do you any good, however.

Example: inherit all values not specified in the C<doomed> profile from
the C<server> profile.

   aemp profile doomed setparent server

=item delparent

Removes the parent again from the profile, if any was set, so the profile
inherits directly from the global default config again.

=item showprofile <name>

Shows the values of the given profile, and only those, no inherited
values.

=item showconfig <name> <key value...>

Shows the I<effective> config, i.e. the values as used by a node started
with the given profile name. Any additional key-value pairs specified
augment the configuration, just as with C<configure>.

If all arguments are omitted, show the global default config.

=back

=cut

use common::sense;

# should come before anything else, so all modules
# will be loaded on each restart
BEGIN {
   if ($ARGV[0] eq "run") {
      shift;

      # d'oh
      require AnyEvent::Watchdog;
      # now we can load extra modules

      require AnyEvent::Watchdog::Util;
      AnyEvent::Watchdog::Util::autorestart (1);
      AnyEvent::Watchdog::Util::heartbeat (300);

      require AnyEvent;
      require AnyEvent::MP::Kernel;
      AnyEvent::MP::Kernel::configure (@ARGV);

      AnyEvent::detect () eq "AnyEvent::Impl::EV"
         ? EV::loop ()
         : AE::cv ()->recv;
   }
}

use Carp ();

use JSON::XS;

use AnyEvent;
use AnyEvent::Util;

use AnyEvent::MP;
use AnyEvent::MP::Config;

sub my_run_cmd {
   my ($cmd) = @_;

   my $cv = &run_cmd;
   my $status = $cv->recv;

   $status
      and die "@$cmd: command failed with exit status $status.";
}

sub gen_cert {
   my_run_cmd [qw(openssl req 
                     -new -nodes -x509 -days 3650
                     -newkey rsa:2048 -keyout /dev/fd/3
                     -batch -subj /CN=AnyEvent::MP
              )],
      "<", "/dev/null",
      ">" , \my $cert,
      "3>", \my $key,
      "2>", "/dev/null";

   "$cert$key"
}

sub init {
   configure profile => "aemp", nodeid => "anon/";
}

our $cfg     = AnyEvent::MP::Config::config;
our $profile = $cfg;

sub trace {
   my ($node) = @_;
   my $cv = AE::cv;
   my %seen;

   my $to = AE::timer 15, 0, sub { exit 1 };

   init;

   my $reply = port {
      my ($node, @neigh) = @_;

      @neigh = grep $_ ne $NODE, @neigh;

      print +(join " ", $node, @neigh), "\n";

      for (@neigh) {
         unless ($seen{$_}++) {
            $cv->begin;
            snd $_, up_nodes => $SELF => $_;
         }
      }

      $cv->end;
   };

   $cv->begin;
   snd $reply, seed => $node;

   $cv->recv;
}

sub docmd;

our %CMD = (
   snd => sub {
      my $port = shift @ARGV;
      init;

      snd $port, @ARGV; @ARGV = ();

      my $cv = AE::cv;
      my $to = AE::timer 5, 0, sub { exit 1 };
      mon $port, $cv;
      my $reply = port sub { &$cv };
      snd node_of $port, snd => $reply, "message sent successfully";

      print join " ", $cv->recv, "\n";
   },

   rpc => sub {
      my $port = shift @ARGV;
      init;

      my $cv = AE::cv;
      my $to = AE::timer 5, 0, sub { exit 1 };
      snd $port, @ARGV, port { &$cv }; @ARGV = ();
      mon $port, $cv;

      print +(substr JSON::XS->new->encode ([$cv->recv]), 1, -1), "\n";
   },

   mon => sub {
      my $port = shift @ARGV;
      init;

      mon $port, my $cv = AE::cv;
      print join " ", $cv->recv, "\n";
   },

   eval => sub {
      my $node = node_of shift @ARGV;
      my $expr = join " ", @ARGV; @ARGV = ();
      init;

      my $cv = AE::cv;
      my $to = AE::timer 5, 0, sub { exit 1 };
      AnyEvent::MP::Kernel::eval_on $node, $expr, port { &$cv };
      mon $node, $cv;

      my ($err, @res) = $cv->recv;

      die $err if length $err;

      print +(substr JSON::XS->new->encode (\@res), 1, -1), "\n";
   },

   trace => sub {
      @ARGV >= 1
         or die "node id missing\n";

      trace shift @ARGV;
   },

   setnodeid => sub {
      @ARGV >= 1
         or die "shared secret missing\n";

      $profile->{nodeid} = shift @ARGV;
      ++$cfg->{dirty};
   },
   delnodeid => sub {
      delete $profile->{nodeid};
      ++$cfg->{dirty};
   },

   setsecret => sub {
      @ARGV >= 1
         or die "shared secret missing\n";

      $profile->{secret} = shift @ARGV;
      ++$cfg->{dirty};
   },
   gensecret => sub {
      $profile->{secret} = AnyEvent::MP::Kernel::alnumbits AnyEvent::MP::Kernel::nonce 64;
      ++$cfg->{dirty};
   },
   delsecret => sub {
      delete $profile->{secret};
      ++$cfg->{dirty};
   },

   setcert => sub {
      @ARGV >= 1
         or die "key+certificate pem filename missing\n";

      open my $fh, "<", $ARGV[0]
         or die "$ARGV[0]: $!";

      local $/;
      $profile->{cert} = <$fh>;
      ++$cfg->{dirty};
   },
   gencert => sub {
      $profile->{cert} = gen_cert;
      ++$cfg->{dirty};
   },
   delcert => sub {
      delete $profile->{cert};
      ++$cfg->{dirty};
   },

   setbinds => sub {
      @ARGV >= 1
         or die "bind addresses missing\n";
      $profile->{binds} = [split /,/, shift @ARGV];
      ++$cfg->{dirty};
   },
   delbinds => sub {
      delete $profile->{binds};
      ++$cfg->{dirty};
   },
   addbind => sub {
      @ARGV >= 1
         or die "bind address missing\n";
      my $bind = shift @ARGV;

      @{ $profile->{binds} } = grep $_ ne $bind, @{ $profile->{binds} };
      push @{ $profile->{binds} }, $bind;
      ++$cfg->{dirty};
   },
   delbind => sub {
      @ARGV >= 1
         or die "bind address missing\n";
      my $bind = shift @ARGV;

      @{ $profile->{binds} } = grep $_ ne $bind, @{ $profile->{binds} };
      ++$cfg->{dirty};
   },

   setseeds => sub {
      @ARGV >= 1
         or die "seed addresses missing\n";
      $profile->{seeds} = [split /,/, shift @ARGV];
      ++$cfg->{dirty};
   },
   delseeds => sub {
      delete $profile->{seeds};
      ++$cfg->{dirty};
   },
   addseed => sub {
      @ARGV >= 1
         or die "seed address missing\n";
      my $seed = shift @ARGV;

      @{ $profile->{seeds} } = grep $_ ne $seed, @{ $profile->{seeds} };
      push @{ $profile->{seeds} }, $seed;
      ++$cfg->{dirty};
   },
   delseed => sub {
      @ARGV >= 1
         or die "seed address missing\n";
      my $seed = shift @ARGV;

      @{ $profile->{seeds} } = grep $_ ne $seed, @{ $profile->{seeds} };
      ++$cfg->{dirty};
   },

   setservices => sub {
      @ARGV >= 1
         or die "service specifications missing\n";
      $profile->{services} = [split /,/, shift @ARGV];
      ++$cfg->{dirty};
   },
   delservices => sub {
      delete $profile->{services};
      ++$cfg->{dirty};
   },
   addservice => sub {
      @ARGV >= 1
         or die "service specification missing\n";
      my $service = shift @ARGV;
      push @{ $profile->{services} }, $service;
      ++$cfg->{dirty};
   },
   delservice => sub {
      @ARGV >= 1
         or die "service specification missing\n";
      my $service = shift @ARGV;
      for (0 .. $#{ $profile->{services} }) {
         next unless $profile->{services}[$_] eq $service;
         splice @{ $profile->{services} }, $_, 1;
         last;
      }
      ++$cfg->{dirty};
   },

   profile => sub {
      @ARGV >= 1
         or die "profile name is missing\n";
      my $name = shift @ARGV;

      $profile = $cfg->{profile}{$name} ||= {};
      ++$cfg->{dirty};
   },
   delprofile => sub {
      @ARGV >= 1
         or die "profile name is missing\n";
      my $name = shift @ARGV;

      delete $cfg->{profile}{$name};
      ++$cfg->{dirty};
   },
   setparent => sub {
      @ARGV >= 1
         or die "profile name is missing\n";

      $profile->{parent} = shift @ARGV;
      ++$cfg->{dirty};
   },
   delparent => sub {
      delete $profile->{parent};
      ++$cfg->{dirty};
   },
   showprofile => sub {
      @ARGV >= 1
         or die "profile name is missing\n";
      my $name = shift @ARGV;

      print JSON::XS->new->pretty->encode ($cfg->{profile}{$name} || {});
   },
   showconfig => sub {
      my $name = @ARGV ? shift @ARGV : AnyEvent::MP::Kernel::_nodename;

      my $profile = AnyEvent::MP::Config::find_profile $name, @ARGV;
      @ARGV = ();

      # make it look nicer:
      delete $profile->{profile};
      delete $profile->{parent};

      print JSON::XS->new->pretty->encode ($profile);
   },

   # undocumented
   _resolve => sub {
      print +(join ",", (AnyEvent::MP::Kernel::_resolve shift @ARGV)->recv), "\n";
   },
);

for (keys %CMD) {
   $CMD{$1} = $CMD{$_} if /^set(.*)$/;
}

sub docmd {
   my $cmd = shift @ARGV;

   $CMD{$cmd}
      or die "$cmd: no such aemp command (try perldoc aemp, or man aemp)";

   $CMD{$cmd}();
}

@ARGV
   or die "Usage: aemp subcommand ... (try perldoc aemp, or man aemp)\n";

docmd while @ARGV;