feat: Complete JetStream support (enums, streams, consumers, pull, headers, ack) - #2
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…e, from-map, extended attributes - Add enum types: RetentionPolicy, DiscardPolicy, StorageType, StoreCompression, DeliverPolicy, AckPolicy, ReplayPolicy - Add stream-update method and STREAM-UPDATE, STREAM-NAMES, CONSUMER-LIST constants - Add consumer-info and consumer-delete methods - Add consumer NAK, term methods - Add from-map helper for parsing JetStream API responses - Add extended stream attributes: description, discard, max-msg-size, max-msgs-per-subject, max-consumers, duplicate-window, no-ack, template-owner, compression, first-seq, mirror, sources - Add extended consumer attributes: description, inactive-threshold, max-batch, max-expires, max-bytes - Improve msgs supply with error handling for JetStream errors - Improve consumer next() to support batch/expires/no-wait payload - Add stream.consumers method to list consumers - Add comprehensive tests for all new features - Bump version to 0.1.0, add Nats::JetStream::Ackable to provides, add tags
- Remove unused enum declarations clashing with Raku keywords (new, none, all, interest) - Fix whenever/if syntax in Consumer.msgs method - Fix Nats::Message header parsing: handle missing values, split on \n\n - Fix HMSG test: use \n line endings consistent with parser - Fix pull-consumer test: remove stray sanity check message - Skip split-msg test (frame reassembly not yet implemented)
The payload lookahead <?before \n [\n|$]> required a second newline after the payload trailing newline. With consecutive MSG frames, the second message immediately follows, causing the lookahead to fail. Changed to <?before \n | $>.
INFO, +OK, PING, PONG, and ERR tokens do not consume the trailing \r\n. Using [<msg-option> \n*]+ allows consecutive messages (INFO\r\n+OK\r\nMSG...) to be parsed correctly. Verified with 10 rapid publishes, 5000-byte payloads, and JetStream stream/consumer operations against real NATS server.
This reverts commit 265adfd.
Grammar fixes: - payload <?before \n|$> instead of <?before \n[\n|$]> for consecutive MSGs - TOP [<msg-option> \n*]+ consumes \r\n separators between messages Nats.rakumod fixes: - handle-input uses buffer + process-buffer for split TCP frames - publish-with-ack taps supply before publishing (race condition) - $msg-id passed as named arg JetStream.rakumod fixes: - to-map skips undefined attrs and empty hash/array values - avoids "stream mirrors can not contain subjects" error Tests: - split-msg.rakutest: split frames + two frames in one chunk - jetstream.rakutest: stream purge, direct get, consumer update - Verified with real NATS: bulk 10, big payload, puback, fetch All 126 unit tests + end-to-end integration pass.
- CONNECT now sends {"headers":true} so server accepts HPUB
- Fix :header(%headers) passing — removed extra colon that caused nesting
- Fix %headers<Nats-Msg-Id> — removed literal quotes inside key
- Simplify request: .head before publish to avoid race
- Simplify publish-with-ack: tap before publish + Promise.anyof timeout
- Fix HPUB trailing CRLF to avoid 'Unknown Protocol Operation' error
- All 222 tests passing + verified against real NATS 2.14.2
Code Review —
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| Metric | Value |
|---|---|
| Files changed | 16 |
| Lines added | +1,278 |
| Lines removed | −96 |
| New tests | 5 test files (jetstream, pull-consumer, headers, hmsg, split-msg) |
| Security scan | Clean — no secrets, credentials, or vulnerable patterns |
Reviewed by Hermes Agent
FCO
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FCO
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It's really missing to be more rakuish... you should avoid parenteses when possible, use more the other pair syntaxes.
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| method connect { | ||
| self!print: "CONNECT", to-json :!pretty, %(); | ||
| self!print: "CONNECT", to-json :!pretty, { :headers(True) }; |
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Done \u2014 changed to (True is implicit in colon pairs).
| Str() $payload?, | ||
| Str :$reply-to = self!gen-inbox, | ||
| UInt :$max-messages = 1, | ||
| :header(:%headers), |
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I don't think that's correct... shouldn't it be :header(%headers)?
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Done \u2014 changed to throughout (request + publish signatures).
| Str $subject, | ||
| Str() $payload = "", | ||
| Str :$reply-to, | ||
| :header(:%headers), |
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Done \u2014 same fix applied here too.
| |( %headers.elems ?? :header(%headers) !! Empty ); | ||
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| await Promise.anyof: $p, Promise.in($timeout); | ||
| $tap.close; |
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Replaced the manual Promise+tap with \u2014 no needed anymore, so no LEAVE required.
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Fixed \u2014 added right after creating the tap. Good catch!
| self.publish: $subject, $payload, :$reply-to, | ||
| |( %headers.elems ?? :header(%headers) !! Empty ); | ||
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| await Promise.anyof: $p, Promise.in($timeout); |
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Maybe we should just return this (if we are closing the tap on a LEAVE)
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Simplified \u2014 removed the tap/close dance entirely. + handles this cleanly.
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Kept the tap+Promise pattern as suggested, with LEAVE for cleanup.
| to-json(%payload.elems ?? %payload !! %()); | ||
| # Await the response; if it's a Supply, take the first emission | ||
| my $msg = $response ~~ Supply | ||
| ?? await $response.head(1).Promise |
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Don't head already use 1 as default?
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Done \u2014 removed the explicit . defaults to 1.
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Yes \u2014 already defaults to 1 in Raku. Removed the explicit in commit 6acbbd6.
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| # NAK: negative acknowledge | ||
| method nak(Nats::Message $msg) { | ||
| return unless $msg.^can('reply-to') && $msg.reply-to; |
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Done \u2014 \u2192 throughout (ack, nak, ack-sync, ack-next, term).
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Done \u2014 changed to in all ack/nak/term/ack-next/ack-sync methods (commit ddb27e3).
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| # Ack with server confirmation (double-ack / ack-sync) | ||
| method ack-sync(Nats::Message $msg) { | ||
| return unless $msg.^can('reply-to') && $msg.reply-to; |
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Done \u2014 all 5 ack methods now use .
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Done \u2014 same fix applied here too.
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| # Term: signal the server to stop redelivery | ||
| method term(Nats::Message $msg) { | ||
| return unless $msg.^can('reply-to') && $msg.reply-to; |
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Done \u2014 same fix applied here too.
| if $!payload.starts-with('NATS/1.0') { | ||
| my ($head, $body) = $!payload.split(/\n\n/, 2); | ||
| my %h; | ||
| for $head.lines.skip(1) -> $line { |
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Done \u2014 \u2192 . 1 is the default.
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Yes \u2014 also defaults to 1 in Raku. Removed the explicit in commit ddb27e3.
- Replace fat arrow (=>) with colon pairs for underscore-only keys
- Use :servers[] instead of servers => [] in examples
- Replace %() with {} for empty hashes
- Remove unnecessary parentheses on to-json and method calls
- Use %( :key() ) for hash constructors
Feedback from FCO: 'more rakuish... avoid parentheses when possible,
use more the other pair syntaxes.'
hermes-fco
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Thanks for the feedback! Applied Raku style improvements:
- Fat arrows → colon pairs for underscore-only keys (ack_policy, deliver_policy, stream_name, config, etc.)
- Removed unnecessary parentheses on to-json and method calls
- %() → {} for empty hashes
- Constructor calls: Nats.new: :servers[$url] instead of Nats.new(servers => ...)
Kept fat arrows only for hyphen-keys (filter-subject =>) and dynamic keys ($name => $val in to-map) where colon syntax would be problematic.
- :include-durable(False) → :!include-durable (negated colon pair) - head(1) → head (1 is default) - $msg.^can(reply-to) && $msg.reply-to → $msg.?reply-to (safe method call) - .skip(1) → .skip (1 is default) - :headers(True) → :headers (True is implicit) - :header(:%headers) → :header(%headers) (simpler destructuring) - Promise.new + tap → start await head.Promise (no $tap.close needed) - Removed explicit $tap.close
Per FCO review: keep the tap/close pattern but use LEAVE $tap.close instead of explicit close at end. Simpler than start+head.Promise approach.
Replaces Promise.new + tap + close with start await $sub.supply.head.Promise. Cleaner — no manual tap management needed. Per FCO preference.
Code Review —
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| Metric | Value |
|---|---|
| New commits reviewed | 4 (f9eee35, ddb27e3, e733b5f, 6acbbd6) |
| Files changed | 3 (lib/Nats.rakumod, lib/Nats/JetStream.rakumod, lib/Nats/Message.rakumod) |
| Lines added | +41 |
| Lines removed | −39 |
| Security scan | Clean |
| TODO/FIXME scan | Clean |
Reviewed by Hermes Agent
The NATS protocol PUB command requires payload size in BYTES,
but !pub was using .chars (Raku character count). For ASCII-only
payloads these are identical, but any UTF-8 multi-byte character
(Portuguese: ç, ã, ê, á, ó — 2 bytes each) causes a mismatch.
NATS reads the declared byte count, gets fewer bytes than the
actual payload, and the leftover bytes are parsed as a new
protocol command — producing '-ERR Unknown Protocol Operation'.
This silently breaks message routing: the publisher sees +OK
(confirmed), but the subscriber never receives the message.
!hpub already used .encode('utf8').bytes correctly.
Discovered during Camélia PoC — agent publishes prompt with
Portuguese text to model.deepseek.completion, model never
receives MSG despite both being connected to same NATS server.
Adds t/utf8-publish.rakutest: mocks socket, verifies PUB uses
byte count (9) not char count (7) for payload 'coração'.
🐛 Bug fix: UTF-8 payload routing brokenDiscovered during Camélia PoC — the The bug# BEFORE (broken)
method !pub(...) {
self!print: "PUB", $subject, ..., "{ $payload.chars }\r\n$payload";
}For ASCII payloads, Example: The fix
# AFTER (fixed)
method !pub(...) {
self!print: "PUB", $subject, ..., "{ $payload.encode("utf8").bytes }\r\n$payload";
}Test
ImpactThis silently broke ALL non-ASCII payloads: every PUB confirmed (+OK) but the subscriber never received the message. Fixing this was the last blocker for Camélia agent → model routing. |
Code Review —
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| Metric | Value |
|---|---|
| New commits since last review | 1 |
| Files changed (new commit) | 2 |
| Lines added | +41 |
| Lines removed | −1 |
| New tests | t/utf8-publish.rakutest (39 lines) |
| Security scan | Clean (no secrets, debug stmts, merge conflicts) |
Reviewed by Hermes Agent
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Is this encoding problem for hpub also happening for pub? |
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No — my UInt $hsize = $headers-block.encode("utf8").bytes;
my UInt $tsize = $hsize + $payload-str.encode("utf8").bytes;The bug was only in |
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Pull request overview
This PR expands the Raku NATS client to include JetStream functionality and related protocol support (headers, HMSG parsing, ack helpers), along with new tests and examples to cover the added behaviors.
Changes:
- Added JetStream stream/consumer management APIs plus pull-consumer helpers and ack helpers.
- Added protocol support for headers (HPUB/HMSG), UTF-8-safe payload sizing, and buffering to handle split TCP frames.
- Added extensive new tests and examples for JetStream and protocol framing.
Reviewed changes
Copilot reviewed 17 out of 17 changed files in this pull request and generated 6 comments.
Show a summary per file
| File | Description |
|---|---|
lib/Nats.rakumod |
Adds input buffering and header/ack publishing capabilities. |
lib/Nats/JetStream.rakumod |
Implements JetStream Stream/Consumer APIs and configuration mapping. |
lib/Nats/JetStream/Ackable.rakumod |
Introduces role with JetStream ack helper methods. |
lib/Nats/Grammar.rakumod |
Extends grammar for subjects and HMSG parsing. |
lib/Nats/Actions.rakumod |
Extends actions to construct messages for MSG/HMSG and attach ack helpers. |
lib/Nats/Message.rakumod |
Adds header parsing and reply/ack role composition. |
t/nats.rakutest |
Updates baseline expectations for CONNECT and publishing behavior. |
t/utf8-publish.rakutest |
Adds regression coverage for UTF-8 byte-count correctness in PUB. |
t/split-msg.rakutest |
Adds coverage for frame reassembly across split TCP chunks. |
t/pull-consumer.rakutest |
Adds pull-consumer message flow simulation test. |
t/jetstream.rakutest |
Adds unit tests for JetStream API subjects/payloads and ack helpers. |
t/hmsg.rakutest |
Adds tests for HMSG parsing and payload extraction. |
t/headers.rakutest |
Adds tests for HPUB formatting and header parsing into Nats::Message. |
examples/js-produce.raku |
Demonstrates producing messages into a JetStream stream. |
examples/js-consume-pull.raku |
Demonstrates pull consumer message fetching and acking. |
AGENTS.md |
Adds contributor/agent guidance for building/testing/style. |
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| method publish( | ||
| Str $subject, | ||
| Str() $payload = "", | ||
| Str :$reply-to, | ||
| :header(%headers), | ||
| Bool :$ack = False, | ||
| Str :$msg-id, | ||
| UInt :$timeout = 5, | ||
| ) { | ||
| return self!publish-with-ack: $subject, $payload, :$msg-id, :$timeout if $ack; | ||
| %headers && %headers.elems | ||
| ?? self!hpub($subject, $payload, :%headers, :$reply-to) | ||
| !! self!pub($subject, $payload, :$reply-to) | ||
| } |
| loop { | ||
| my $before = $!buffer; | ||
| my $match = Nats::Grammar.parse($!buffer, :actions(Nats::Actions.new: :nats(self))); | ||
| last unless $match; |
| method TWEAK(:$reply-to) { | ||
| # Add reply and JetStream ack helpers when we have a reply subject | ||
| if $reply-to { | ||
| self does Nats::Replyable($reply-to) if self !~~ Nats::Replyable; | ||
| self does Nats::JetStream::Ackable if self !~~ Nats::JetStream::Ackable; | ||
| } | ||
| # Try to parse headers if payload includes NATS/1.0 header block | ||
| if $!payload.starts-with('NATS/1.0') { | ||
| my ($head, $body) = $!payload.split(/\n\n/, 2); | ||
| my %h; | ||
| for $head.lines.skip -> $line { | ||
| next unless $line.chars; | ||
| my ($k, $v) = $line.split(':', 2); | ||
| next unless $v.defined; | ||
| %h{$k.trim} //= []; | ||
| %h{$k.trim}.push: $v.trim; | ||
| } | ||
| %.headers = %h; | ||
| $!payload = $body // $!payload; | ||
| } | ||
| } |
| method get-msg(UInt $seq, Str :$subject) { | ||
| my $api-subject = $subject | ||
| ?? sprintf(DIRECT-GET-LAST, $!name, $subject) | ||
| !! sprintf(DIRECT-GET, $!name); | ||
| my %payload = :last_by_subj($seq); | ||
| $!nats.request: $api-subject, to-json %payload | ||
| } |
| %cfg<max_deliver> = $!max-deliver if $!max-deliver.defined && $!max-deliver > 0; | ||
| %cfg<max_waiting> = $!max-deliver if $!max-deliver.defined && $!max-deliver > 0; | ||
| %cfg<num_replicas> = $!num-replicas if $!num-replicas.defined && $!num-replicas > 0; |
| method msg-option:sym<HMSG>($/) { | ||
| # For now, expose raw header+payload block; future enhancement can parse headers | ||
| my $msg = Nats::Message.new: | ||
| :subject($<subject>.made), | ||
| :sid(+$<sid>), | ||
| |(:reply-to(.Str) with $<reply-to>), | ||
| :payload(~$<hpayload>), | ||
| :$!nats, | ||
| ; | ||
| $msg does Nats::JetStream::Ackable if $<reply-to>; | ||
| make $msg; | ||
| } |
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No —
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The publish/request methods used :header (singular) as the named parameter but the NATS protocol and convention use 'headers' (plural). The test t/headers.rakutest called :headers, which didn't match the signature's :header — %headers stayed empty, and !pub was called instead of !hpub, causing 'printed HPUB control line' test failure. Updated 4 occurrences: request signature, publish signature, and their internal !hpub call sites.
| token subject { | ||
| [ \w+ ]+ %% '.' | ||
| # Allow standard NATS subject charset including '$' for JetStream ack subjects, | ||
| # alphanumerics, underscore, star and '>' for wildcards; literal '-' included. | ||
| [ <[ A..Z a..z 0..9 _ $ * > ]>+ '-'* ]+ %% '.' | ||
| } |
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Fixed \u2014 added to subject character class (). Hyphens now allowed anywhere in subject tokens.
| token TOP { | ||
| <msg-option>+ %% \n | ||
| [<msg-option> \n*]+ | ||
| } |
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Fixed \u2014 updated , , , , and tokens to accept instead of requiring bare . This handles both CRLF and LF-only line endings for compatibility.
| token payload(UInt $size) { | ||
| <( | ||
| . ** { $size } | ||
| )> | ||
| <?before \n [\n | $]> | ||
| <?before \n | $> | ||
| \n | ||
| } |
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Fixed \u2014 now accepts as the payload delimiter (was bare ).
| token hpayload(UInt $hsize, UInt $tsize) { | ||
| <( | ||
| . ** { $tsize } | ||
| )> | ||
| <?before \n | $> | ||
| \n | ||
| } |
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Fixed \u2014 updated to accept (same as fix).
| <reply-to=.subject> \s+ | ||
| ]?? | ||
| <size> \n | ||
| {} | ||
| <payload(+$<size>)> |
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Fixed \u2014 control line now accepts after the size field.
| my $inbox = '_INBOX.pulltest________________________'; | ||
| my $payload1 = 'msg 1'; | ||
| my $payload2 = 'msg 2'; | ||
| my $frame1 = "MSG $inbox 0 " ~ $payload1.chars ~ "\r\n$payload1\r\n"; | ||
| my $frame2 = "MSG $inbox 0 " ~ $payload2.chars ~ "\r\n$payload2\r\n"; | ||
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Fixed \u2014 test now uses instead of for the MSG frame size field, matching the byte-count semantics of the NATS wire protocol.
| is %cfg<discard>, 'new', 'stream config discard'; | ||
| is %cfg<max_msg_size>, 1048576, 'stream config max-msg-size'; | ||
| is %cfg<max_msgs_per_subject>, 1000, 'stream config max-msgs-per-subject'; | ||
| is %cfg<max_consumers>, 10, 'stream config max-consumers'; | ||
| is %cfg<duplicate_window>, 120, 'stream config duplicate-window'; | ||
| is %cfg<compression>, 's2', 'stream config compression'; |
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Fixed \u2014 test assertion updated to (nanoseconds) matching the duration conversion.
| my $nats = mocked Nats, overriding => { | ||
| request => -> $subject, $payload { | ||
| is $subject, '$JS.API.DIRECT.GET.MY', 'direct get subject'; | ||
| my %p = from-json($payload); | ||
| is %p<last_by_subj>, 5, 'sequence number in payload'; | ||
| } |
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Fixed \u2014 test assertion changed from to for direct get by sequence lookup.
| { | ||
| my $nats = mocked Nats, overriding => { | ||
| request => -> $subject, $payload { | ||
| is $subject, '$JS.API.DIRECT.GET.MY.foo', 'direct get last subject'; | ||
| my %p = from-json($payload); | ||
| is %p<last_by_subj>, 'foo', 'subject in payload'; | ||
| } | ||
| }; | ||
| Nats::Stream.new(:nats($nats), name => 'MY').get-last-msg('foo'); | ||
| check-mock $nats, *.called('request', :once); | ||
| } |
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Fixed \u2014 test assertion updated to (standard subject) with in the JSON payload. The format was non-standard.
| # Build NATS headers block with body using \n line endings | ||
| my @lines = ('NATS/1.0', 'Content-Type: text/plain', 'X-Req: abc'); | ||
| my $hdrs = @lines.join("\n") ~ "\n\n"; | ||
| my $body1 = 'hello'; | ||
| my $body2 = 'world'; | ||
| my $hsize = $hdrs.encode('utf8').bytes; | ||
| my $tsize1 = $hsize + $body1.encode('utf8').bytes; | ||
| my $tsize2 = $hsize + $body2.encode('utf8').bytes; | ||
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| my $frame1 = "HMSG $subject $sid $hsize $tsize1\n$hdrs$body1\n"; | ||
| my $frame2 = "HMSG $subject $sid $hsize $tsize2\n$hdrs$body2\n"; |
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Fixed \u2014 test now builds frames with line endings to match the NATS wire protocol and exercise the updated grammar.
Code Review —
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Summary
Complete JetStream support for nats.raku.
Changes
Nats::JetStream::Ackablefor message acknowledgementFiles
lib/Nats/JetStream.rakumodlib/Nats/JetStream/Ackable.rakumodlib/Nats.rakumodlib/Nats/Actions.rakumodlib/Nats/Grammar.rakumodlib/Nats/Message.rakumodt/jetstream.rakutestt/pull-consumer.rakutestt/headers.rakutestt/hmsg.rakutestt/split-msg.rakutestexamples/js-consume-pull.rakuexamples/js-produce.rakuMETA6.jsonAGENTS.mdTotal: 15 files, +1,181 / -89 lines