From a678d30e62ba742cc8d350a9b86287d02969cb94 Mon Sep 17 00:00:00 2001 From: Nick Gunn Date: Sat, 15 Jan 2022 08:28:49 +1100 Subject: [PATCH] Initial commit --- .formatter.exs | 4 + .github/workflows/elixir.yml | 32 ++ .github/workflows/release.yml | 38 ++ .gitignore | 29 ++ CHANGELOG.md | 4 + LICENSE.md | 22 ++ README.md | 50 +++ lib/stagger.ex | 129 +++++++ lib/stagger/application.ex | 18 + lib/stagger/msg_queue.ex | 308 ++++++++++++++++ mix.exs | 70 ++++ mix.lock | 27 ++ test/LICENSE | 674 ++++++++++++++++++++++++++++++++++ test/stagger_badfile_test.exs | 12 + test/stagger_prop_test.exs | 193 ++++++++++ test/stagger_test.exs | 212 +++++++++++ test/test_helper.exs | 1 + 17 files changed, 1823 insertions(+) create mode 100644 .formatter.exs create mode 100644 .github/workflows/elixir.yml create mode 100644 .github/workflows/release.yml create mode 100644 .gitignore create mode 100644 CHANGELOG.md create mode 100644 LICENSE.md create mode 100644 README.md create mode 100644 lib/stagger.ex create mode 100644 lib/stagger/application.ex create mode 100644 lib/stagger/msg_queue.ex create mode 100644 mix.exs create mode 100644 mix.lock create mode 100644 test/LICENSE create mode 100644 test/stagger_badfile_test.exs create mode 100644 test/stagger_prop_test.exs create mode 100644 test/stagger_test.exs create mode 100644 test/test_helper.exs diff --git a/.formatter.exs b/.formatter.exs new file mode 100644 index 0000000..d2cda26 --- /dev/null +++ b/.formatter.exs @@ -0,0 +1,4 @@ +# Used by "mix format" +[ + inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"] +] diff --git a/.github/workflows/elixir.yml b/.github/workflows/elixir.yml new file mode 100644 index 0000000..7df4a77 --- /dev/null +++ b/.github/workflows/elixir.yml @@ -0,0 +1,32 @@ +name: CI + +on: [push, pull_request] + +jobs: + build: + + name: Build and test + runs-on: ubuntu-latest + + env: + MIX_ENV: test + GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} + steps: + - uses: actions/checkout@v2 + with: + fetch-depth: 0 + - name: Set up Elixir + uses: erlef/setup-beam@988e02bfe678367a02564f65ca2e37726dc0268f + with: + elixir-version: '1.12.3' # Define the elixir version [required] + otp-version: '24.1' # Define the OTP version [required] + - name: Restore dependencies cache + uses: actions/cache@v2 + with: + path: deps + key: ${{ runner.os }}-mix-${{ hashFiles('**/mix.lock') }} + restore-keys: ${{ runner.os }}-mix- + - name: Install dependencies + run: mix deps.get + - name: Run tests + run: mix coveralls.github diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml new file mode 100644 index 0000000..b6ccd5f --- /dev/null +++ b/.github/workflows/release.yml @@ -0,0 +1,38 @@ +name: Release + +on: workflow_dispatch + +jobs: + build: + + name: Publish hex package + runs-on: ubuntu-latest + + env: + GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} + HEX_API_KEY: ${{ secrets.HEX_API_KEY }} + steps: + - uses: actions/checkout@v2 + with: + fetch-depth: 0 + - name: Fetch tags + run: git fetch --tags --force + - name: Set up Elixir + uses: erlef/setup-beam@988e02bfe678367a02564f65ca2e37726dc0268f + with: + elixir-version: '1.12.3' # Define the elixir version [required] + otp-version: '24.1' # Define the OTP version [required] + - name: Restore dependencies cache + uses: actions/cache@v2 + with: + path: deps + key: ${{ runner.os }}-mix-${{ hashFiles('**/mix.lock') }} + restore-keys: ${{ runner.os }}-mix- + - name: Install dependencies + run: mix deps.get + - name: Compile + run: mix compile + - name: Build hex package + run: mix hex.build + - name: Publish hex package + run: mix hex.publish --yes diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..349f537 --- /dev/null +++ b/.gitignore @@ -0,0 +1,29 @@ +# The directory Mix will write compiled artifacts to. +/_build/ + +# If you run "mix test --cover", coverage assets end up here. +/cover/ + +# The directory Mix downloads your dependencies sources to. +/deps/ + +# Where third-party dependencies like ExDoc output generated docs. +/doc/ + +# Ignore .fetch files in case you like to edit your project deps locally. +/.fetch + +# If the VM crashes, it generates a dump, let's ignore it too. +erl_crash.dump + +# Also ignore archive artifacts (built via "mix archive.build"). +*.ez + +# Ignore package tarball (built via "mix hex.build"). +stagger-*.tar + +# Temporary files, for example, from tests. +/tmp/ + +# LSP +.elixir_ls \ No newline at end of file diff --git a/CHANGELOG.md b/CHANGELOG.md new file mode 100644 index 0000000..a25a0e8 --- /dev/null +++ b/CHANGELOG.md @@ -0,0 +1,4 @@ +# Changelog + +## 0.1.0 (2022-01-26) - Initial revision + diff --git a/LICENSE.md b/LICENSE.md new file mode 100644 index 0000000..16e8829 --- /dev/null +++ b/LICENSE.md @@ -0,0 +1,22 @@ +# MIT License + +Copyright (c) 2022 Nick Gunn + +Permission is hereby granted, free of charge, to any person obtaining +a copy of this software and associated documentation files (the +"Software"), to deal in the Software without restriction, including +without limitation the rights to use, copy, modify, merge, publish, +distribute, sublicense, and/or sell copies of the Software, and to +permit persons to whom the Software is furnished to do so, subject to +the following conditions: + +The above copyright notice and this permission notice shall be +included in all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, +EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF +MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND +NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE +LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION +OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION +WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. \ No newline at end of file diff --git a/README.md b/README.md new file mode 100644 index 0000000..92d8129 --- /dev/null +++ b/README.md @@ -0,0 +1,50 @@ +# Stagger + +[![Build Status](https://github.com/ausimian/stagger/actions/workflows/elixir.yml/badge.svg)](https://github.com/ausimian/stagger/actions?query=workflow%3A%22CI%22) +[![Coverage Status](https://coveralls.io/repos/github/ausimian/stagger/badge.svg?branch=main)](https://coveralls.io/github/ausimian/stagger?branch=main) +[![Hex](https://img.shields.io/hexpm/v/stagger.svg)](https://hex.pm/packages/stagger) +[![Hex Docs](https://img.shields.io/badge/hex-docs-blue.svg)](https://hexdocs.pm/stagger) + +Point-to-point, durable message-queues as GenStage producers. + +Stagger enables the creation of GenStage processes that enqueue terms to simple, +file-backed message-queues, allowing the producer and consumer to run independently +of each other, possibly at different times. + + +----------+ +----------+ +----------+ +------------+ + | Upstream | | MsgQueue | | MsgQueue | | Downstream | + | | -> | | <- | | <---> | | + | Client | | Producer | | Consumer | | Processing | + +----------+ +----------+ +----------+ +------------+ + | | read + write | | + +------+ + | FILE | + | | + | | + +------+ + +Your upstream client writes its events into the message-queue (provided by +Stagger), which persists them to local storage. Your (GenStage) consumer, subscribes +to the producer and receives events, via this local storage. +## Installation + +The package can be installed by adding `stagger` to your list of dependencies in `mix.exs`: + +```elixir +def deps do + [ + {:stagger, "~> 0.1.0"} + ] +end +``` + +The docs can be found at . + +## Copyright and License + +Copyright (c) 2022, Nick Gunn + +Stagger runtime source code is licensed under the [MIT License](LICENSE.md). +Stagger test source code is licensed under the [GPL3 License](test/LICENSE). + diff --git a/lib/stagger.ex b/lib/stagger.ex new file mode 100644 index 0000000..0b95ef2 --- /dev/null +++ b/lib/stagger.ex @@ -0,0 +1,129 @@ +defmodule Stagger do + @moduledoc ~S""" + Point-to-point, durable message-queues as GenStage producers. + + Stagger enables the creation of GenStage processes that enqueue terms to simple, + file-backed message-queues, allowing the producer and consumer to run independently + of each other, possibly at different times. + + +----------+ +----------+ +----------+ +------------+ + | Upstream | | MsgQueue | | MsgQueue | | Downstream | + | | -> | | <- | | <---> | | + | Client | | Producer | | Consumer | | Processing | + +----------+ +----------+ +----------+ +------------+ + | | read + write | | + +------+ + | FILE | + | | + | | + +------+ + + Your upstream client writes its events into the message-queue (provided by + Stagger), which persists them to local storage. Your (GenStage) consumer, subscribes + to the producer and receives events, via this local storage. + + ## Producers + + Upstream clients must first open their message-queue, via `open/1`, and then use the + resulting process to enqueue writes, via `write/2`. + + {:ok, pid} = Stagger.open("/path/to/msg/queue") + ... + :ok = Stagger.write(pid, "foo") + :ok = Stagger.write(pid, "bar") + :ok = Stagger.write(pid, "baz") + + The process created via `open/1` is the GenStage MsgQueue - by writing entries to it, + it will satisfy demand from a downstream consumer. + + ## Consumers + + Downstream clients are GenStage consumers. They must also open the message-queue, via + `open/1` and then subscribe use existing GenStage subscription facilities: + + def init(args) do + {:ok, pid} = Stagger.open("/path/to/msg/queue") + {:ok, sub} = GenStage.sync_subscribe(self(), to: pid, ack: last_processed()) + ... + end + + def handle_events(events, _from, stage) do + ... + end + + ## Sequence numbers + + Sequence numbers are used to control the events seen by a subscriber. Every event + delivered to a consumer is a 2-tuple of `{seqno, msg}` and it is the consumer's + responsibility to successfully record this sequence number as having been + processed. + + A consumer must indicate its last-processed sequence number by passing `ack: N` in + the subscription options (pass `ack: 0` when no such number exists) whenever it + (re)subscribes. Event delivery will resume from the Nth + 1 event. + + Every message _written_ to the message-queue is assigned an incrementing sequence number + by the Stagger process. When an existing message queue is re-opened, the process will + first recover the last written number, using that as the base for any subsequent writes. + + ## Purging + + In order to prevent unconstrained growth of the message-queue file, a consumer may + periodically purge the queue of old entries by passing a `purge: N` option when it + (re)subscribes e.g: + + last = last_processed() + {:ok, sub} = GenStage.sync_subscribe(self(), to: pid, ack: last, purge: last) + + All entries _up to and including_ N are removed from the head of message-queue file. + The value of N will be capped to no more than the value of the last ack'd message. + + To summarize: + + - `ack: N` determines that the next delivered message will have a seqno of N + 1 + - `purge: M` is a hint to the producer to remove messages 1..M from the head of + the message queue. + + ## Why not RabbitMQ? + + If you think you need something like RabbitMQ, you probably do :-). Stagger is + intended to be a lightweight durable message queue with minimal dependencies. + """ + + @doc """ + Open a message-queue file, returning the pid responsible for managing it. + + The resulting pid can be used by upstream clients to enqueue messages via `write/2`, or + may be used as the target of a GenStage subscribe operation. + + The following option may be passed to the function: + + * `hibernate_after: N` - After a period of _N_ milliseconds, the returned process will + hibernate. If unspecified, defaults to 15 seconds. Pass `hibernate_after: :infinite` + to inhibit this behaviour. This option only takes effect if the process managing the + queue is created by the call to `open/2`. + + """ + @spec open(binary, Keyword.t) :: :ignore | {:error, any} | {:ok, any} | {:ok, pid, any} + def open(path, opts \\ []) when is_binary(path) do + args = Map.new(opts) |> Map.put(:path, path) + case DynamicSupervisor.start_child(Stagger.MsgQueueSupervisor, {Stagger.MsgQueue, args}) do + {:ok, pid} -> + {:ok, pid} + {:error, {:already_started, pid}} -> + {:ok, pid} + error -> + error + end + end + + @doc """ + Write a term to the message-queue. + """ + @spec write(pid :: atom | pid | {atom, any} | {:via, atom, any}, term :: any, timeout :: :infinite | non_neg_integer()) :: :ok | {:error, any} + def write(pid, term, timeout \\ 5000) do + Stagger.MsgQueue.write(pid, term, timeout) + end + +end diff --git a/lib/stagger/application.ex b/lib/stagger/application.ex new file mode 100644 index 0000000..8e303c3 --- /dev/null +++ b/lib/stagger/application.ex @@ -0,0 +1,18 @@ +defmodule Stagger.Application do + @moduledoc false + + use Application + + @impl true + def start(_type, _args) do + children = [ + # A registry used to hold each MsgQueue, keyed by the path of the MsgQueue file + %{id: Stagger.MsgQueueRegistry, start: {Registry, :start_link, [[keys: :unique, name: Stagger.MsgQueueRegistry]]}}, + # The supervisor for the MsgQueue processes + {DynamicSupervisor, strategy: :one_for_one, name: Stagger.MsgQueueSupervisor}, + ] + + opts = [strategy: :one_for_one, name: Stagger.Supervisor] + Supervisor.start_link(children, opts) + end +end diff --git a/lib/stagger/msg_queue.ex b/lib/stagger/msg_queue.ex new file mode 100644 index 0000000..5c26c24 --- /dev/null +++ b/lib/stagger/msg_queue.ex @@ -0,0 +1,308 @@ +defmodule Stagger.MsgQueue do + @moduledoc false + use GenServer, restart: :transient + + require Logger + + defstruct [ + path: nil, # Path to the file + wr_file: nil, # File object used to write new messages + wr_seqno: 0, # The most recent written seqno + subscriber: nil, # The current subscriber + monitor: nil, # The monitor on the current subscriber + rd_file: nil, # File object used to read messages + rd_seqno: 0, # The most recent read seqno + demand: 0, # The current demand, + timeout: :infinite # The hibernation timeout + ] + + @chunk_size 65_536 + @default_timeout 15_000 + + # + # Stagger.MsgQueue is a GenServer that implements the GenStage Producer protocol + # directly. The justification for this is: + # + # * It has single-consumer, point-to-point semantics with recovery and + # acknowledgement. + # * It implicitly does its own buffering via the underlying file. + # * It allows the use `handle_continue`, something not currently supported by + # GenStage. + # + # It currently uses two file 'handles' to the same file, one for writing and + # one for reading. It could be possible to reduce this to a single file if the + # positions were managed explicitly. + # + # The format of the file is very simple: Each message is encoded as follows + # + # -+-----------------+--------+--------------+- + # | Sequence number | Size | Message | + # -+-----------------+--------+--------------+- + # 8 bytes 4 bytes bytes + # + # Both the sequence number and the size are encoded as little-endian + # + + @spec start_link(%{:path => binary, optional(any) => any}) :: :ignore | {:error, any} | {:ok, pid} + def start_link(%{path: path} = args) when is_binary(path) do + GenServer.start_link(__MODULE__, args, name: {:via, Registry, {Stagger.MsgQueueRegistry, path}}) + end + + @spec write(stage :: atom | pid | {atom, any} | {:via, atom, any}, term :: any, timeout :: :infinity | non_neg_integer()) :: any + def write(stage, term, timeout) do + # Using `term_to_iovec` makes it more efficient if the term itself contains binaries + GenServer.call(stage, {:write, :erlang.term_to_iovec(term)}, timeout) + end + + @impl true + def init(%{path: path} = args) when is_binary(path) do + timeout = Map.get(args, :hibernate_after, @default_timeout) + {:ok, file, seqno} = open_write_file(path) + {:ok, %__MODULE__{path: path, wr_file: file, wr_seqno: seqno, timeout: timeout}, timeout} + end + + @impl true + def handle_call({:write, data}, _from, %__MODULE__{wr_file: file, wr_seqno: seqno} = state) do + next = seqno + 1 + size = :erlang.iolist_size(data) + blob = [<> | data] + reply = :file.write(file, blob) + + {:reply, reply, %__MODULE__{state | wr_seqno: next}, {:continue, :fulfill}} + end + + @impl true + def handle_info({:"$gen_producer", from, {:ask, new}}, %__MODULE__{timeout: timeout} = state) do + # Handle new demand providing it comes from our current subscription + case state do + %__MODULE__{subscriber: ^from, demand: current} -> + {:noreply, %__MODULE__{state | demand: current + new}, {:continue, :fulfill}} + _ -> + {:noreply, state, timeout} + end + end + def handle_info({:"$gen_producer", {pid, ref} = from, {:subscribe, cancel, opts}}, %__MODULE__{subscriber: subscriber, timeout: timeout} = state) do + # Handle subscription / resubscription + cond do + from == subscriber -> + Process.send(pid, {:"$gen_consumer", {self(), ref}, {:cancel, :duplicated_subscription}}, [:noconnect]) + {:noreply, state, timeout} + is_nil(cancel) && not is_nil(subscriber) -> + Process.send(pid, {:"$gen_consumer", {self(), ref}, {:cancel, :oversubscribed}}, [:noconnect]) + {:noreply, state, timeout} + true -> + reason = if cancel, do: elem(cancel, 1), else: nil + {:noreply, subscribe(from, opts, unsubscribe(reason, state)), {:continue, :fulfill}} + end + end + def handle_info({:"$gen_producer", _from, {:cancel, reason}}, %__MODULE__{timeout: timeout} = state) do + # Handle unsubscription + {:noreply, unsubscribe(reason, state), timeout} + end + def handle_info({:DOWN, ref, :process, pid, _reason}, %__MODULE__{subscriber: {pid, _}, monitor: ref, timeout: timeout} = state) do + # Handle subscriber loss + {:noreply, unsubscribe(nil, state), timeout} + end + def handle_info({:DOWN, _, _, _, _}, %__MODULE__{timeout: timeout} = state) do + # Ignore loss of old subscribers + {:noreply, state, timeout} + end + def handle_info(:timeout, state) do + {:noreply, state, :hibernate} + end + + @impl true + def handle_continue(:fulfill, state) do + fulfill(state) + end + + defp subscribe({pid, _ref} = from, opts, %__MODULE__{path: path, wr_file: wr_file, wr_seqno: wr_seqno, subscriber: nil, monitor: nil, rd_file: nil} = state) do + # ack is the seqno that subscriber last processed + ack = seqno_from_options(opts, :ack, 0) + # last is the maximum sequence number that can be purged from the file + last = min(ack, seqno_from_options(opts, :purge, 0)) + + # close the file, purge it (if possible), and then recover + :ok = :file.close(wr_file) + :ok = purge_up_to(path, min(last + 1, wr_seqno)) + # we should have the same wr_seqno after recovery + {:ok, wr_file, ^wr_seqno} = open_write_file(path) + + {:ok, rd_file} = :file.open(path, [:read, :write, :raw, :binary]) + {:ok, _position} = move_to_seqno(rd_file, ack + 1) + + %__MODULE__{state | subscriber: from, monitor: Process.monitor(pid), wr_file: wr_file, rd_file: rd_file, rd_seqno: ack} + end + + defp unsubscribe(_reason, %__MODULE__{subscriber: nil} = state), do: state + defp unsubscribe(reason, %__MODULE__{subscriber: subscriber, monitor: ref, rd_file: rd_file} = state) do + {sub, oldref} = subscriber + Process.send(sub, {:"$gen_consumer", {self(), oldref}, {:cancel, reason}}, [:noconnect]) + Process.demonitor(ref) + :ok = :file.close(rd_file) + %__MODULE__{state | subscriber: nil, monitor: nil, rd_file: nil, rd_seqno: 0} + end + + defp fulfill(%__MODULE__{subscriber: subscriber, demand: demand, timeout: timeout} = state) when is_nil(subscriber) or demand == 0 do + # Don't send events if there's no subscriber or no demand + {:noreply, state, timeout} + end + defp fulfill(%__MODULE__{wr_seqno: seqno, rd_seqno: seqno, timeout: timeout} = state) do + # Don't send events if the subscriber has caught up + {:noreply, state, timeout} + end + defp fulfill(%__MODULE__{rd_file: file, rd_seqno: seqno, demand: demand} = state) do + {:ok, posn} = :file.position(file, :cur) + fulfill_from_file(state, demand, seqno, posn, <<>>, []) + end + + # + # `fulfill_from_file` and `fulfill_from_chunk` are a couple of mutually recursive + # functions that traverse the file from its current position, accumulating events + # to deliver to the consumer. + # + defp fulfill_from_file(state, demand, seqno, posn, _prev, events) when demand == 0 do + fulfilled(state, demand, seqno, posn, events) + end + defp fulfill_from_file(%__MODULE__{rd_file: file} = state, demand, seqno, posn, prev, events) do + case :file.read(file, @chunk_size) do + {:ok, chunk} -> + fulfill_from_chunk(state, demand, seqno, posn, prev <> chunk, events) + :eof -> + fulfilled(state, demand, seqno, posn, events) + end + end + + defp fulfill_from_chunk(state, demand, seqno, posn, _prev, events) when demand == 0 do + fulfilled(state, demand, seqno, posn, events) + end + defp fulfill_from_chunk(state, demand, seqno, posn, chunk, events) do + case chunk do + <> -> + cond do + next == seqno + 1 -> + term = :erlang.binary_to_term(data) + fulfill_from_chunk(state, demand - 1, next, posn + 8 + 4 + size, rest, [{next, term} | events]) + next > seqno + 1 -> + fulfill_from_chunk(state, demand , seqno + 1, posn, chunk, events) + true -> + fulfilled(state, demand, seqno, posn, events) + end + _ -> + fulfill_from_file(state, demand, seqno, posn, chunk, events) + end + end + + defp fulfilled(%__MODULE__{subscriber: {sub, ref}, rd_file: file, timeout: timeout} = state, demand, seqno, posn, events) do + {:ok, ^posn} = :file.position(file, posn) + send(sub, {:"$gen_consumer", {self(), ref}, :lists.reverse(events)}) + {:noreply, %__MODULE__{state | rd_seqno: seqno, demand: demand}, timeout} + end + + defp purge_up_to(path, seqno) do + {:ok, infile} = :file.open(path, [:read, :raw, :binary]) + {:ok, inlength} = :file.position(infile, :eof) + {:ok, 0} = :file.position(infile, :bof) + {:ok, position} = move_to_seqno(infile, seqno) + case position do + 0 -> + :ok = :file.close(infile) + _ -> + tmppath = "#{path}.tmp" + try do + {:ok, outfile} = :file.open(tmppath, [:write, :raw, :binary]) + {:ok, _} = :file.position(outfile, {:bof, inlength - position}) + :ok = :file.truncate(outfile) + {:ok, 0} = :file.position(outfile, :bof) + + :ok = copy_file(infile, outfile) + :ok = :file.close(outfile) + :ok = :file.close(infile) + :ok = :file.rename(tmppath, path) + after + File.rm_rf(tmppath) + end + end + end + + defp copy_file(infile, outfile) do + case :file.read(infile, @chunk_size) do + {:ok, chunk} -> + :ok = :file.write(outfile, chunk) + copy_file(infile, outfile) + :eof -> + :ok + end + end + + defp open_write_file(path) do + {:ok, file} = :file.open(path, [:read, :write, :raw, :binary]) + {:ok, _good, _bad, seqno} = recover(file) + {:ok, file, seqno} + end + + defp move_to_seqno(file, seqno) do + {:ok, cur} = :file.position(file, :cur) + {:ok, off} = move_to_seqno_file(file, seqno, <<>>, cur) + :file.position(file, off) + end + + defp move_to_seqno_file(file, seqno, prev, off) do + case :file.read(file, @chunk_size) do + {:ok, chunk} -> + move_to_seqno_chunk(file, seqno, prev <> chunk, off) + :eof -> + {:ok, off} + end + end + + defp move_to_seqno_chunk(file, seqno, chunk, off) do + case chunk do + <> when next >= seqno -> + {:ok, off} + <<_next::little-size(64), size::little-size(32), _::binary-size(size), rest::binary>> -> + move_to_seqno_chunk(file, seqno, rest, off + 8 + 4 + size) + remainder -> + move_to_seqno_file(file, seqno, remainder, off) + end + end + + defp recover(file) do + {:ok, cur} = :file.position(file, :cur) + {:ok, good, bad, _seqno} = result = recover_from_file(file, 0, <<>>, cur) + {:ok, ^good} = :file.position(file, good) + if bad > 0 do + :ok = :file.truncate(file) + end + result + end + + defp recover_from_file(file, seqno, prev, posn) do + case :file.read(file, @chunk_size) do + {:ok, chunk} -> + recover_from_chunk(file, seqno, prev <> chunk, posn) + :eof -> + {:ok, posn, byte_size(prev), seqno} + end + end + + defp recover_from_chunk(file, seqno, chunk, off) do + case chunk do + <> + when seqno == 0 or seqno + 1 == next -> + recover_from_chunk(file, next, rest, off + 8 + 4 + size) + remainder -> + recover_from_file(file, seqno, remainder, off) + end + end + + defp seqno_from_options(opts, kw, dv) do + case Keyword.get(opts, kw, dv) do + v when is_integer(v) and v >= 0 -> + v + _ -> + 0 + end + end + +end diff --git a/mix.exs b/mix.exs new file mode 100644 index 0000000..b192a39 --- /dev/null +++ b/mix.exs @@ -0,0 +1,70 @@ +defmodule Stagger.MixProject do + use Mix.Project + + def project do + version = get_version() + [ + app: :stagger, + version: version, + elixir: "~> 1.12", + start_permanent: Mix.env() == :prod, + deps: deps(), + name: "Stagger", + description: "Point-to-point, durable message-queues", + source_url: "https://github.com/ausimian/stagger", + docs: docs(version), + test_coverage: [tool: ExCoveralls], + preferred_cli_env: [ + coveralls: :test + ], + package: package() + ] + end + + # Run "mix help compile.app" to learn about applications. + def application do + [ + extra_applications: [:logger], + mod: {Stagger.Application, []} + ] + end + + # Run "mix help deps" to learn about dependencies. + defp deps do + [ + {:gen_stage, "~> 1.1"}, + {:credo, "~> 1.6", only: [:test, :dev], runtime: false}, + {:ex_doc, "~> 0.27", only: [:dev], runtime: false}, + {:propcheck, "~> 1.4", only: [:test, :dev]}, + {:excoveralls, "~> 0.10", only: [:test]} + ] + end + + defp docs(version) do + [ + main: "Stagger", + source_ref: "v#{version}" + ] + end + + defp get_version do + case System.cmd("git", ~w[describe --dirty=+dirty], stderr_to_stdout: true) do + {"v" <> version, 0} -> + version + |> String.trim + |> Version.parse!() + |> to_string() + _ -> + "0.0.0-dev" + end + end + + defp package() do + [ + files: ~w(lib .formatter.exs mix.exs README.md LICENSE.md CHANGELOG.md), + licenses: ["MIT"], + links: %{"GitHub" => "https://github.com/ausimian/stagger"} + ] + end + +end diff --git a/mix.lock b/mix.lock new file mode 100644 index 0000000..099e770 --- /dev/null +++ b/mix.lock @@ -0,0 +1,27 @@ +%{ + "bunt": {:hex, :bunt, "0.2.0", "951c6e801e8b1d2cbe58ebbd3e616a869061ddadcc4863d0a2182541acae9a38", [:mix], [], "hexpm", "7af5c7e09fe1d40f76c8e4f9dd2be7cebd83909f31fee7cd0e9eadc567da8353"}, + "certifi": {:hex, :certifi, "2.8.0", "d4fb0a6bb20b7c9c3643e22507e42f356ac090a1dcea9ab99e27e0376d695eba", [:rebar3], [], "hexpm", "6ac7efc1c6f8600b08d625292d4bbf584e14847ce1b6b5c44d983d273e1097ea"}, + "credo": {:hex, :credo, "1.6.2", "2f82b29a47c0bb7b72f023bf3a34d151624f1cbe1e6c4e52303b05a11166a701", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:file_system, "~> 0.2.8", [hex: :file_system, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "ae9dc112bc368e7b145c547bec2ed257ef88955851c15057c7835251a17211c6"}, + "dialyxir": {:hex, :dialyxir, "1.1.0", "c5aab0d6e71e5522e77beff7ba9e08f8e02bad90dfbeffae60eaf0cb47e29488", [:mix], [{:erlex, ">= 0.2.6", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm", "07ea8e49c45f15264ebe6d5b93799d4dd56a44036cf42d0ad9c960bc266c0b9a"}, + "earmark_parser": {:hex, :earmark_parser, "1.4.19", "de0d033d5ff9fc396a24eadc2fcf2afa3d120841eb3f1004d138cbf9273210e8", [:mix], [], "hexpm", "527ab6630b5c75c3a3960b75844c314ec305c76d9899bb30f71cb85952a9dc45"}, + "erlex": {:hex, :erlex, "0.2.6", "c7987d15e899c7a2f34f5420d2a2ea0d659682c06ac607572df55a43753aa12e", [:mix], [], "hexpm", "2ed2e25711feb44d52b17d2780eabf998452f6efda104877a3881c2f8c0c0c75"}, + "ex_doc": {:hex, :ex_doc, "0.27.3", "d09ed7ab590b71123959d9017f6715b54a448d76b43cf909eb0b2e5a78a977b2", [:mix], [{:earmark_parser, "~> 1.4.19", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1", [hex: :makeup_erlang, repo: "hexpm", optional: false]}], "hexpm", "ee60b329d08195039bfeb25231a208749be4f2274eae42ce38f9be0538a2f2e6"}, + "excoveralls": {:hex, :excoveralls, "0.14.4", "295498f1ae47bdc6dce59af9a585c381e1aefc63298d48172efaaa90c3d251db", [:mix], [{:hackney, "~> 1.16", [hex: :hackney, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "e3ab02f2df4c1c7a519728a6f0a747e71d7d6e846020aae338173619217931c1"}, + "file_system": {:hex, :file_system, "0.2.10", "fb082005a9cd1711c05b5248710f8826b02d7d1784e7c3451f9c1231d4fc162d", [:mix], [], "hexpm", "41195edbfb562a593726eda3b3e8b103a309b733ad25f3d642ba49696bf715dc"}, + "gen_stage": {:hex, :gen_stage, "1.1.2", "b1656cd4ba431ed02c5656fe10cb5423820847113a07218da68eae5d6a260c23", [:mix], [], "hexpm", "9e39af23140f704e2b07a3e29d8f05fd21c2aaf4088ff43cb82be4b9e3148d02"}, + "hackney": {:hex, :hackney, "1.18.0", "c4443d960bb9fba6d01161d01cd81173089686717d9490e5d3606644c48d121f", [:rebar3], [{:certifi, "~>2.8.0", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "~>6.1.0", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "~>1.0.0", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "~>1.1", [hex: :mimerl, repo: "hexpm", optional: false]}, {:parse_trans, "3.3.1", [hex: :parse_trans, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "~>1.1.0", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}, {:unicode_util_compat, "~>0.7.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "9afcda620704d720db8c6a3123e9848d09c87586dc1c10479c42627b905b5c5e"}, + "idna": {:hex, :idna, "6.1.1", "8a63070e9f7d0c62eb9d9fcb360a7de382448200fbbd1b106cc96d3d8099df8d", [:rebar3], [{:unicode_util_compat, "~>0.7.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "92376eb7894412ed19ac475e4a86f7b413c1b9fbb5bd16dccd57934157944cea"}, + "jason": {:hex, :jason, "1.3.0", "fa6b82a934feb176263ad2df0dbd91bf633d4a46ebfdffea0c8ae82953714946", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "53fc1f51255390e0ec7e50f9cb41e751c260d065dcba2bf0d08dc51a4002c2ac"}, + "libgraph": {:hex, :libgraph, "0.13.3", "20732b7bafb933dcf7351c479e03076ebd14a85fd3202c67a1c197f4f7c2466b", [:mix], [], "hexpm", "78f2576eef615440b46f10060b1de1c86640441422832052686df53dc3c148c6"}, + "makeup": {:hex, :makeup, "1.0.5", "d5a830bc42c9800ce07dd97fa94669dfb93d3bf5fcf6ea7a0c67b2e0e4a7f26c", [:mix], [{:nimble_parsec, "~> 0.5 or ~> 1.0", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "cfa158c02d3f5c0c665d0af11512fed3fba0144cf1aadee0f2ce17747fba2ca9"}, + "makeup_elixir": {:hex, :makeup_elixir, "0.15.2", "dc72dfe17eb240552857465cc00cce390960d9a0c055c4ccd38b70629227e97c", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.1", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "fd23ae48d09b32eff49d4ced2b43c9f086d402ee4fd4fcb2d7fad97fa8823e75"}, + "makeup_erlang": {:hex, :makeup_erlang, "0.1.1", "3fcb7f09eb9d98dc4d208f49cc955a34218fc41ff6b84df7c75b3e6e533cc65f", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "174d0809e98a4ef0b3309256cbf97101c6ec01c4ab0b23e926a9e17df2077cbb"}, + "metrics": {:hex, :metrics, "1.0.1", "25f094dea2cda98213cecc3aeff09e940299d950904393b2a29d191c346a8486", [:rebar3], [], "hexpm", "69b09adddc4f74a40716ae54d140f93beb0fb8978d8636eaded0c31b6f099f16"}, + "mimerl": {:hex, :mimerl, "1.2.0", "67e2d3f571088d5cfd3e550c383094b47159f3eee8ffa08e64106cdf5e981be3", [:rebar3], [], "hexpm", "f278585650aa581986264638ebf698f8bb19df297f66ad91b18910dfc6e19323"}, + "nimble_parsec": {:hex, :nimble_parsec, "1.2.0", "b44d75e2a6542dcb6acf5d71c32c74ca88960421b6874777f79153bbbbd7dccc", [:mix], [], "hexpm", "52b2871a7515a5ac49b00f214e4165a40724cf99798d8e4a65e4fd64ebd002c1"}, + "parse_trans": {:hex, :parse_trans, "3.3.1", "16328ab840cc09919bd10dab29e431da3af9e9e7e7e6f0089dd5a2d2820011d8", [:rebar3], [], "hexpm", "07cd9577885f56362d414e8c4c4e6bdf10d43a8767abb92d24cbe8b24c54888b"}, + "propcheck": {:hex, :propcheck, "1.4.1", "c12908dbe6f572032928548089b34ff9d40672d5d70f1562e3a9e9058d226cc9", [:mix], [{:libgraph, "~> 0.13", [hex: :libgraph, repo: "hexpm", optional: false]}, {:proper, "~> 1.4", [hex: :proper, repo: "hexpm", optional: false]}], "hexpm", "e1b088f574785c3c7e864da16f39082d5599b3aaf89086d3f9be6adb54464b19"}, + "proper": {:hex, :proper, "1.4.0", "89a44b8c39d28bb9b4be8e4d715d534905b325470f2e0ec5e004d12484a79434", [:rebar3], [], "hexpm", "18285842185bd33efbda97d134a5cb5a0884384db36119fee0e3cfa488568cbb"}, + "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.6", "cf344f5692c82d2cd7554f5ec8fd961548d4fd09e7d22f5b62482e5aeaebd4b0", [:make, :mix, :rebar3], [], "hexpm", "bdb0d2471f453c88ff3908e7686f86f9be327d065cc1ec16fa4540197ea04680"}, + "unicode_util_compat": {:hex, :unicode_util_compat, "0.7.0", "bc84380c9ab48177092f43ac89e4dfa2c6d62b40b8bd132b1059ecc7232f9a78", [:rebar3], [], "hexpm", "25eee6d67df61960cf6a794239566599b09e17e668d3700247bc498638152521"}, +} diff --git a/test/LICENSE b/test/LICENSE new file mode 100644 index 0000000..94a9ed0 --- /dev/null +++ b/test/LICENSE @@ -0,0 +1,674 @@ + GNU GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU General Public License is a free, copyleft license for +software and other kinds of works. + + The licenses for most software and other practical works are designed +to take away your freedom to share and 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But first, please read +. diff --git a/test/stagger_badfile_test.exs b/test/stagger_badfile_test.exs new file mode 100644 index 0000000..8909d6a --- /dev/null +++ b/test/stagger_badfile_test.exs @@ -0,0 +1,12 @@ +defmodule StaggerBadFileTest do + use ExUnit.Case + + @testfile "/tmp/badfile" + + test "corrupt file is truncated" do + {:ok, file} = :file.open(@testfile, [:raw, :write, :binary]) + :ok = :file.write(file, :crypto.strong_rand_bytes(1234)) + :ok = :file.close(file) + {:ok, _producer} = Stagger.open(@testfile, hibernate_after: 1000) + end +end diff --git a/test/stagger_prop_test.exs b/test/stagger_prop_test.exs new file mode 100644 index 0000000..7bc9c1a --- /dev/null +++ b/test/stagger_prop_test.exs @@ -0,0 +1,193 @@ +defmodule StaggerProps do + + require Logger + + # + # This is stateful property test that uses a Stagger.MsgQueue process and a consumer + # in tandem to confirm the expected behavior of the former. The set of commands + # that are generated are used to drive both processes. + # + + defmodule Subscriber do + use GenStage + + # + # The subscriber api deliberately has a number of blocking calls to make + # test construction easier. For example, the subscribe call will block until + # confirmation of the subscription has been received. The others follow a + # similar pattern. + # + + def start_link(args), do: GenStage.start_link(__MODULE__, args) + def subscribe(consumer, producer), do: GenStage.call(consumer, {:subscribe, producer}) + def unsubscribe(consumer), do: GenStage.call(consumer, :unsubscribe) + def resubscribe(consumer), do: GenStage.call(consumer, :resubscribe) + def ask(subscriber, demand), do: GenStage.call(subscriber, {:ask, demand}) + def get_rcvd(subscriber, upto), do: GenStage.call(subscriber, {:get_rcvd, upto}) + + @impl true + def init(args) do + ack = args[:ack] || 0 + {:consumer, %{subscription: nil, ack: ack, caller: nil, rcvd: %{}, upto: nil}} + end + + @impl true + def handle_subscribe(:producer, _opts, from, %{caller: caller} = state) when not is_nil(caller) do + GenStage.reply(caller, :ok) + {:manual, %{state | subscription: from, caller: nil}} + end + + @impl true + def handle_cancel({_, :resubscribe}, from, %{subscription: from} = state) do + {:noreply, [], %{state | subscription: nil}} + end + def handle_cancel({_, :resubscribe}, _from, %{} = state) do + {:noreply, [], state} + end + def handle_cancel(_reason, from, %{subscription: from, caller: caller} = state) do + unless is_nil(caller) do + GenStage.reply(caller, :ok) + end + {:noreply, [], %{state | subscription: nil, caller: nil}} + end + + @impl true + def handle_call({:subscribe, producer}, from, %{subscription: nil, ack: ack, caller: nil} = state) do + :ok = GenStage.async_subscribe(self(), to: producer, cancel: :temporary, ack: ack, purge: ack) + {:noreply, [], %{state | caller: from}} + end + def handle_call(:unsubscribe, from, %{subscription: sub, caller: nil} = state) when not is_nil(sub) do + :ok = GenStage.cancel(sub, :normal) + {:noreply, [], %{state | caller: from}} + end + def handle_call(:resubscribe, from, %{subscription: {pid, tag}, ack: ack, caller: nil} = state) do + :ok = GenStage.async_resubscribe(self(), tag, :resubscribe, to: pid, cancel: :temporary, ack: ack, purge: ack) + {:noreply, [], %{state | caller: from}} + end + def handle_call({:ask, demand}, _from, %{subscription: sub} = state) do + reply = GenStage.ask(sub, demand) + {:reply, reply, [], state} + end + def handle_call({:get_rcvd, upto}, _from, %{rcvd: rcvd} = state) when is_map_key(rcvd, upto) do + {:reply, copy_rcvd(rcvd, upto), [], state} + end + def handle_call({:get_rcvd, upto}, from, state) do + {:noreply, [], %{state | upto: {from, upto}}} + end + + @impl true + def handle_events([], _from, state) do + {:noreply, [], try_copy(state)} + end + def handle_events([{seqno, msg} | msgs], from, %{rcvd: rcvd, ack: ack} = state) do + handle_events(msgs, from, %{state | rcvd: Map.put(rcvd, seqno, msg), ack: max(seqno, ack)}) + end + + defp try_copy(%{rcvd: rcvd, upto: {from, upto}} = state) when is_map_key(rcvd, upto) do + :ok = GenServer.reply(from, copy_rcvd(rcvd, upto)) + %{state | upto: nil} + end + defp try_copy(state), do: state + + + defp copy_rcvd(rcvd, upto, acc \\ %{}) + defp copy_rcvd(rcvd, upto, acc) when is_map_key(rcvd, upto) do + copy_rcvd(rcvd, upto - 1, Map.put(acc, upto, Map.fetch!(rcvd, upto))) + end + defp copy_rcvd(_rcvd, _upto, acc), do: acc + + end + + use ExUnit.Case + use PropCheck + use PropCheck.StateM + + alias Stagger.MsgQueue, as: Producer + alias StaggerProps.Subscriber, as: Consumer + + defstruct msgs: %{}, demand: 0, rd_seqno: 0, wr_seqno: 0, subscribed: false + alias __MODULE__, as: Model + + @filepath "/tmp/staggerprops" + + property "run the msg queue", [:verbose, numtests: 1000] do + forall cmds <- commands(__MODULE__, %Model{}) do + {:ok, _} = File.rm_rf(@filepath) + {:ok, producer} = Producer.start_link(%{path: @filepath}) + {:ok, consumer} = start_supervised(Consumer) + {history, model, result} = run_commands(Model, cmds, producer: producer, consumer: consumer) + :ok = stop_supervised(Consumer) + :ok = GenServer.stop(producer) + + (result == :ok) + |> aggregate(command_names(cmds)) + |> when_fail(IO.puts(""" + History: #{inspect(history)} + Model: #{inspect(model)} + Result: #{inspect(result)} + """)) + end + end + + def command(%{wr_seqno: wr_seqno, rd_seqno: rd_seqno, demand: demand}) do + oneof([ + {:call, Consumer, :subscribe, [{:var, :consumer}, {:var, :producer}]}, + {:call, Consumer, :unsubscribe, [{:var, :consumer}]}, + {:call, Consumer, :resubscribe, [{:var, :consumer}]}, + {:call, Producer, :write, [{:var, :producer}, term(), 5000]}, + {:call, Consumer, :ask, [{:var, :consumer}, (such_that n <- pos_integer(), when: n < 10)]}, + {:call, Consumer, :get_rcvd, [{:var, :consumer}, min(wr_seqno, rd_seqno + demand)]} + ]) + end + + def precondition(%Model{subscribed: subscribed}, {:call, Consumer, :subscribe, _args}), do: not subscribed + def precondition(%Model{subscribed: subscribed}, {:call, Consumer, :unsubscribe, _args}), do: subscribed + def precondition(%Model{subscribed: subscribed}, {:call, Consumer, :resubscribe, _args}), do: subscribed + def precondition(%Model{}, {:call, Producer, :write, _args}), do: true + def precondition(%Model{subscribed: true, demand: 0}, {:call, Consumer, :ask, _args}), do: true + def precondition(%Model{subscribed: true}, {:call, Consumer, :get_rcvd, [_, upto]}) do + upto > 0 + end + def precondition(_model, _call), do: false + + def postcondition(%Model{subscribed: subscribed}, {:call, Consumer, :subscribe, _args}, result) do + (not subscribed) && result == :ok + end + def postcondition(%Model{subscribed: subscribed}, {:call, Consumer, :unsubscribe, _args}, result) do + subscribed && (result == :ok) + end + def postcondition(%Model{subscribed: subscribed}, {:call, Consumer, :resubscribe, _args}, result) do + subscribed && (result == :ok) + end + def postcondition(%Model{}, {:call, Consumer, :ask, _args}, result) do + result == :ok + end + def postcondition(%Model{}, {:call, Producer, :write, _args}, result) do + result == :ok + end + def postcondition(%Model{msgs: msgs, rd_seqno: prev}, {:call, Consumer, :get_rcvd, [_, upto]}, result) do + (prev + 1)..upto // 1 |> Enum.all?(fn seqno -> Map.has_key?(result, seqno) && Map.fetch!(result, seqno) == Map.fetch!(msgs, seqno) end) + end + + def next_state(%Model{} = model, _result, {:call, Consumer, :subscribe, _args}) do + %Model{model | subscribed: true} + end + def next_state(%Model{} = model, _result, {:call, Consumer, :unsubscribe, _args}) do + %Model{model | subscribed: false} + end + def next_state(%Model{} = model, _result, {:call, Consumer, :resubscribe, _args}) do + %Model{model | demand: 0} + end + def next_state(%Model{} = model, _result, {:call, Consumer, :ask, [_consumer, demand]}) do + %Model{model | demand: demand} + end + def next_state(%Model{msgs: msgs, wr_seqno: seqno} = model, _result, {:call, Producer, :write, [_, term, _]}) do + next = seqno + 1 + %Model{model | wr_seqno: next, msgs: Map.put(msgs, next, term)} + end + def next_state(%Model{rd_seqno: rd_seqno, demand: demand} = model, _result, {:call, Consumer, :get_rcvd, [_, upto]}) do + %Model{model | rd_seqno: max(rd_seqno, upto), demand: demand - (max(0, upto - rd_seqno))} + end + + def initial_state, do: %Model{} +end diff --git a/test/stagger_test.exs b/test/stagger_test.exs new file mode 100644 index 0000000..c5980ee --- /dev/null +++ b/test/stagger_test.exs @@ -0,0 +1,212 @@ +defmodule StaggerTest do + use ExUnit.Case + doctest Stagger + + require Logger + + defmodule Consumer do + use GenStage, restart: :transient + + def start_link(_args) do + GenStage.start_link(__MODULE__, nil) + end + + def wait_for(stage, seqno, timeout \\ 5000) do + GenStage.call(stage, {:wait_for, seqno}, timeout) + end + + @impl true + def init(_args) do + {:consumer, %{}} + end + + @impl true + def handle_call({:wait_for, seqno}, from, state) do + if Map.has_key?(state, seqno) do + {:reply, state[seqno], [], state} + else + {:noreply, [], Map.put(state, seqno, from)} + end + end + + @impl true + def handle_events(events, _from, state) do + {:noreply, [], process(events, state)} + end + + @impl true + def handle_cancel(_reason, _from, _state) do + {:noreply, [], %{}} + end + + defp process([], state), do: state + defp process([{seqno, msg} | events], state) do + if Map.has_key?(state, seqno) do + GenStage.reply(state[seqno], msg) + end + process(events, Map.put(state, seqno, msg)) + end + end + + @testfile "/tmp/stagger-test" + + setup do + File.rm_rf!(@testfile) + {:ok, producer} = Stagger.open(@testfile, hibernate_after: 1000) + {:ok, consumer} = start_supervised(StaggerTest.Consumer) + + on_exit(fn -> + GenStage.stop(producer) + end) + + {:ok, producer: producer, consumer: consumer} + end + + test "invalid file name" do + {:error, _} = Stagger.open("") + end + + test "one producer per file", context do + producer = context[:producer] + {:ok, ^producer} = Stagger.open(@testfile) + end + + test "producer hibernates", context do + producer = context[:producer] + + # Should cause hibernation + Process.sleep(2000) + + {:current_function, {:erlang, :hibernate, 3}} = Process.info(producer, :current_function) + end + + test "single consumer only", context do + producer = context[:producer] + consumer = context[:consumer] + + {:ok, additional} = start_supervised(StaggerTest.Consumer, id: :additional) + + {:ok, _tag} = GenStage.sync_subscribe(consumer, to: producer, ack: 0, cancel: :transient) + {:ok, _tag} = GenStage.sync_subscribe(additional, to: producer, ack: 0, cancel: :temporary) + + :ok = Stagger.write(producer, "foo") + "foo" = StaggerTest.Consumer.wait_for(consumer, 1) + + try do + "foo" = StaggerTest.Consumer.wait_for(additional, 1, 1000) + catch + :exit, reason -> + assert {:timeout, _call} = reason + end + end + + test "post events after subscription", context do + producer = context[:producer] + consumer = context[:consumer] + + {:ok, _tag} = GenStage.sync_subscribe(consumer, to: producer, ack: 0, cancel: :transient) + + :ok = Stagger.write(producer, "foo") + :ok = Stagger.write(producer, "bar") + :ok = Stagger.write(producer, "baz") + + "foo" = StaggerTest.Consumer.wait_for(consumer, 1) + "bar" = StaggerTest.Consumer.wait_for(consumer, 2) + "baz" = StaggerTest.Consumer.wait_for(consumer, 3) + + end + + test "post events before subscription", context do + producer = context[:producer] + consumer = context[:consumer] + + :ok = Stagger.write(producer, "foo") + :ok = Stagger.write(producer, "bar") + :ok = Stagger.write(producer, "baz") + + {:ok, _tag} = GenStage.sync_subscribe(consumer, to: producer, ack: 0, cancel: :transient) + + "foo" = StaggerTest.Consumer.wait_for(consumer, 1) + "bar" = StaggerTest.Consumer.wait_for(consumer, 2) + "baz" = StaggerTest.Consumer.wait_for(consumer, 3) + end + + test "post events across subscription", context do + producer = context[:producer] + consumer = context[:consumer] + + :ok = Stagger.write(producer, "foo") + :ok = Stagger.write(producer, "bar") + + {:ok, _tag} = GenStage.sync_subscribe(consumer, to: producer, ack: 0, cancel: :transient) + "foo" = StaggerTest.Consumer.wait_for(consumer, 1) + + :ok = Stagger.write(producer, "baz") + + "bar" = StaggerTest.Consumer.wait_for(consumer, 2) + "baz" = StaggerTest.Consumer.wait_for(consumer, 3) + end + + test "post events across subscriptions", context do + producer = context[:producer] + consumer = context[:consumer] + + {:ok, ref} = GenStage.sync_subscribe(consumer, to: producer, ack: 0, cancel: :transient) + + :ok = Stagger.write(producer, "foo") + :ok = Stagger.write(producer, "bar") + + "foo" = StaggerTest.Consumer.wait_for(consumer, 1) + "bar" = StaggerTest.Consumer.wait_for(consumer, 2) + + GenStage.cancel({producer, ref}, :normal) + + {:ok, _ref} = GenStage.sync_subscribe(consumer, to: producer, ack: 1, cancel: :transient) + "bar" = StaggerTest.Consumer.wait_for(consumer, 2) + + :ok = Stagger.write(producer, "baz") + "baz" = StaggerTest.Consumer.wait_for(consumer, 3) + end + + @tag :missing + test "missing events", context do + producer = context[:producer] + consumer = context[:consumer] + + :ok = Stagger.write(producer, "foo") + :ok = Stagger.write(producer, "bar") + :ok = Stagger.write(producer, "baz") + + {:ok, ref} = GenStage.sync_subscribe(consumer, to: producer, ack: 2, purge: 2, cancel: :transient) + "baz" = StaggerTest.Consumer.wait_for(consumer, 3) + + {:ok, _ref} = GenStage.sync_resubscribe(consumer, ref, :normal, to: producer, ack: 1, cancel: :transient) + "baz" = StaggerTest.Consumer.wait_for(consumer, 3) + end + + test "producer ignores spurious down messages", context do + producer = context[:producer] + consumer = context[:consumer] + + send(producer, {:DOWN, make_ref(), :process, self(), :test}) + + GenStage.sync_subscribe(consumer, to: producer, ack: 0, cancel: :transient) + + :ok = Stagger.write(producer, "foo") + "foo" = StaggerTest.Consumer.wait_for(consumer, 1) + end + + test "mini-stress", context do + producer = context[:producer] + consumer = context[:consumer] + + {:ok, _ref} = GenStage.sync_subscribe(consumer, to: producer, ack: 0, cancel: :transient) + blobs = for _ <- 1..10_000, do: :crypto.strong_rand_bytes(23_456) + blobs + |> Enum.each(fn blob -> Stagger.write(producer, blob) end) + + blobs + |> Enum.with_index + |> Enum.all?(fn {blob, index} -> blob == StaggerTest.Consumer.wait_for(consumer, index + 1) end) + end +end diff --git a/test/test_helper.exs b/test/test_helper.exs new file mode 100644 index 0000000..869559e --- /dev/null +++ b/test/test_helper.exs @@ -0,0 +1 @@ +ExUnit.start()