3 # back-end trigger server for CouchDB monitoring changes feed:
5 # http://wiki.apache.org/couchdb/HTTP_database_API#Changes
7 # implements state machine using document which you cen put with:
9 # curl -X PUT http://localhost:5984/monitor/df -d '{"trigger":{"command":"df -P","format":"table"}}'
11 # DEFAULT TRIGGER EXECUTE SHELL COMMANDS. IT IS NOT SECURE IF YOUR COUCHDB ISN'T SECURE!
16 use lib 'common/mojo/lib';
20 use Time::HiRes qw(time);
21 use Data::Dump qw(dump);
23 my ( $url, $trigger_path ) = @ARGV;
25 $url ||= 'http://localhost:5984/monitor';
26 $trigger_path ||= 'trigger/shell.pm' ;
28 our $database = $1 if $url =~ m{/(\w+)/?$};
30 require $trigger_path if -e $trigger_path;
32 my $uid = `hostname -s`;
38 my $client = Mojo::UserAgent->new;
39 our $json = Mojo::JSON->new;
40 sub info { warn $_[0], " ",$json->encode($_[1]),$/ }
41 sub debug { info "# $_[0]", $_[1] }
44 $client->keep_alive_timeout(90); # couchdb timeout is 60s
48 my $changes_feed = "$url/_changes?feed=continuous;include_docs=true;since=$seq";
49 info 'GET' => $changes_feed;
50 my $tx = $client->build_tx( GET => $changes_feed );
52 my ( $content, $body ) = @_;
54 return if length($body) == 0; # empty chunk, heartbeat?
56 debug 'BODY' => $body;
58 foreach ( split(/\r?\n/, $body) ) { # we can get multiple documents in one chunk
60 my $change = $json->decode($_);
62 if ( exists $change->{error} ) {
64 } elsif ( exists $change->{last_seq} ) {
65 $seq = $change->{last_seq};
66 } elsif ( $change->{seq} <= $seq ) {
67 info "ERROR: stale" => $change;
68 } elsif ( exists $change->{changes} ) {
70 my $id = $change->{id} || warn "no id?";
71 my $rev = $change->{changes}->[0]->{rev} || warn "no rev?";
72 $seq = $change->{seq} || warn "no seq?";
74 debug 'change' => $change;
76 if ( filter($change) ) {
78 if ( ! exists $change->{doc}->{trigger}->{active} ) {
79 $change->{doc}->{trigger}->{active} = [ $uid, time() ];
81 debug 'TRIGGER start PUT ', $change->{doc};
82 my $client = Mojo::UserAgent->new;
83 my $res = $client->put( "$url/$id" => $json->encode( $change->{doc} ) )->res;
84 warn "code ", $res->code, dump( $res->json );
85 if ( $res->code == 409 ) {
86 info "TRIGGER ABORTED started on another worker? ", $res->error;
88 } elsif ( $res->code != 201 ) {
89 info "ERROR $url/$id ", $res->code;
93 } elsif ( $change->{doc}->{trigger}->{active}->[0] eq $uid ) {
94 if ( exists $change->{doc}->{trigger}->{active}->[2] ) {
95 warn "allready executed";
99 debug "TRIGGER execute ", $change->{doc};
102 push @{ $change->{doc}->{trigger}->{active} }, time(), 0; # last timestamp
103 warn "change ",dump $change;
105 my $client = Mojo::UserAgent->new;
106 my $res = $client->put( "$url/$id" => $json->encode( $change->{doc} ) )->res;
107 warn "code ", $res->code;
108 if ( my $json = $res->json ) {
110 $change->{doc}->{_rev} = $json->{rev};
111 info "TRIGGER finish ", $change->{doc};
113 info "ERROR $url/$id", $tx->error;
119 warn "UNKNOWN", $json->encode($change);
129 die "ERROR ", $json->encode($error) if $error;