From b8d8b3dbd88ab42fc8f050af0d18fc4dd66d7ffe Mon Sep 17 00:00:00 2001
From: Catalin Mititiuc
Date: Thu, 9 Jan 2025 11:25:52 -0800
Subject: Handle installing Pandoc
---
lib/pandoc.ex | 360 +++++++++++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 343 insertions(+), 17 deletions(-)
(limited to 'lib/pandoc.ex')
diff --git a/lib/pandoc.ex b/lib/pandoc.ex
index f1f07f7..ca30847 100644
--- a/lib/pandoc.ex
+++ b/lib/pandoc.ex
@@ -1,17 +1,130 @@
defmodule Pandoc do
+ # https://github.com/jgm/pandoc/releases
+ @latest_version "3.6.1"
+
@moduledoc """
- Documentation for `Pandoc`.
+ Pandoc is an installer, runner and watcher for [pandoc](https://pandoc.org).
+
+ ## Profiles
+
+ You can define multiple pandoc profiles. By default, there is a profile
+ called `:default` which you can configure its args, current directory and
+ environment. You can make the args dynamic by defining a function.
+
+ config :pandoc,
+ version: "#{@latest_version}",
+ default: [
+ args: fn extra_args ->
+ {_, [input_file], _} = OptionParser.parse(extra_args, switches: [])
+ ~w(--output=../priv/static/posts/\#{Path.rootname(input_file)}.html)
+ end,
+ cd: Path.expand("../documents", __DIR__)
+ ]
+
+ ## Pandoc configuration
+
+ There are four global configurations for the pandoc application:
+
+ * `:version` - the expected pandoc version
+
+ * `:version_check` - whether to perform the version check or not.
+ Useful when you manage the pandoc executable with an external
+ tool
+
+ * `:cacerts_path` - the directory to find certificates for
+ https connections
+
+ * `:path` - the path to find the pandoc executable at. By
+ default, it is automatically downloaded and placed inside
+ the `_build` directory of your current app
+
+ Overriding the `:path` is not recommended, as we will automatically download
+ and manage `pandoc` for you. But in case you can't download it, you may want
+ to set the `:path` to a configurable system location.
+ """
+
+ require Logger
+
+ @doc false
+ # Latest known version at the time of publishing.
+ def latest_version, do: @latest_version
+
+ @doc """
+ Returns the configured pandoc version.
"""
+ def configured_version do
+ Application.get_env(:pandoc, :version, latest_version())
+ end
+
+ @doc """
+ Returns the configuration for the given profile.
+
+ Returns nil if the profile does not exist.
+ """
+ def config_for!(profile) when is_atom(profile) do
+ Application.get_env(:pandoc, profile) ||
+ raise ArgumentError, """
+ unknown pandoc profile. Make sure the profile is defined in your config/config.exs file, such as:
- def run(profile, ["--watch" | _]) do
- config = Application.get_env(:pandoc, profile)
- opts = [cd: config[:cd] || File.cwd!()]
- dirs = [opts[:cd], Path.join(opts[:cd], "_drafts")]
+ config :pandoc,
+ version: "#{@latest_version}",
+ #{profile}: [
+ cd: Path.expand("../documents", __DIR__)
+ ]
+ """
+ end
+
+ @doc """
+ Returns the path to the executable.
+
+ The executable may not be available if it was not yet installed.
+ """
+ def bin_path do
+ name = "pandoc-#{target()}"
+
+ Application.get_env(:pandoc, :path) ||
+ if Code.ensure_loaded?(Mix.Project) do
+ relative_build_dir = Mix.Project.build_path() |> Path.dirname() |> Path.relative_to_cwd()
+ project_dir = Path.dirname(Mix.Project.project_file())
+ Path.join([project_dir, relative_build_dir, name])
+ else
+ Path.expand("_build/#{name}")
+ end
+ end
+
+ @doc """
+ Returns the version of the pandoc executable.
+
+ Returns `{:ok, version_string}` on success or `:error` when the executable
+ is not available.
+ """
+ def bin_version do
+ path = bin_path()
+
+ with true <- File.exists?(path),
+ {out, 0} <- System.cmd(path, ["--version"]),
+ [vsn] <- Regex.run(~r/#{Path.basename(path)} ([^\s]+)/, out, capture: :all_but_first) do
+ {:ok, vsn}
+ else
+ _ -> :error
+ end
+ end
+
+ @doc """
+ Starts a file system watcher that runs the given command with `args` when a
+ file event is received for a file that matches the given pattern.
+
+ The given args will be appended to the configured args. The task output will
+ be streamed directly to stdio.
+ """
+ def watch(profile, extra_args \\ [], pattern \\ ~r/\.md$/) when is_atom(profile) do
+ config = config_for!(profile)
+ opts = [dirs: [config[:cd] || File.cwd!()]]
ref =
__MODULE__.Supervisor
|> Supervisor.start_child(
- Supervisor.child_spec({Pandoc.Watcher, [profile, dirs: dirs]},
+ Supervisor.child_spec({Pandoc.Watcher, [profile, opts, pattern, extra_args]},
restart: :transient,
id: __MODULE__.Watcher
)
@@ -27,9 +140,24 @@ defmodule Pandoc do
end
end
- def run(profile, path) do
- config = Application.get_env(:pandoc, profile)
- args = config[:args] || []
+ @doc """
+ Runs the given command with `args`.
+
+ The given args will be appended to the configured args. The task output will
+ be streamed directly to stdio. It returns the status of the underlying call.
+ """
+ def run(profile, extra_args) when is_atom(profile) and is_list(extra_args) do
+ config = config_for!(profile)
+
+ args =
+ case config[:args] do
+ args_fn when is_function(args_fn) -> args_fn.(extra_args)
+ args -> args || []
+ end
+
+ if args == [] and extra_args == [] do
+ raise "no arguments passed to pandoc"
+ end
opts = [
cd: config[:cd] || File.cwd!(),
@@ -37,17 +165,215 @@ defmodule Pandoc do
stderr_to_stdout: true
]
- new_filename =
- path |> Path.basename() |> String.replace_suffix(".md", ".html") |> String.slice(11..-1//1)
+ {parsed_args, _, _} = OptionParser.parse(args, switches: [output: :string])
+ {_, input_files, _} = OptionParser.parse(extra_args, switches: [])
+
+ if parsed_args[:output] &&
+ not File.cd!(opts[:cd], fn ->
+ input_files |> Enum.map(&File.exists?(&1)) |> Enum.all?()
+ end) do
+ parsed_args[:output] |> Path.expand(opts[:cd]) |> File.rm!()
+ else
+ bin_path() |> System.cmd(args ++ extra_args, opts) |> elem(1)
+ end
+ end
+
+ defp start_unique_install_worker() do
+ ref =
+ __MODULE__.Supervisor
+ |> Supervisor.start_child(
+ Supervisor.child_spec({Task, &install/0}, restart: :transient, id: __MODULE__.Installer)
+ )
+ |> case do
+ {:ok, pid} -> pid
+ {:error, {:already_started, pid}} -> pid
+ end
+ |> Process.monitor()
+
+ receive do
+ {:DOWN, ^ref, _, _, _} -> :ok
+ end
+ end
+
+ @doc """
+ Installs, if not available, and then runs `pandoc`.
+
+ This task may be invoked concurrently and it will avoid concurrent installs.
+
+ Returns the same as `run/2`.
+ """
+ def install_and_run(profile, args) do
+ File.exists?(bin_path()) || start_unique_install_worker()
+
+ run(profile, args)
+ end
+
+ @doc """
+ The default URL to install Pandoc from.
+ """
+ def default_base_url do
+ "https://github.com/jgm/pandoc/releases/download/$version/pandoc-$version-$target.tar.gz"
+ end
+
+ @doc """
+ Installs pandoc with `configured_version/0`.
+
+ If invoked concurrently, this task will perform concurrent installs.
+ """
+ def install(base_url \\ default_base_url()) do
+ version = configured_version()
+ tmp_opts = if System.get_env("MIX_XDG"), do: %{os: :linux}, else: %{}
+
+ tmp_dir =
+ freshdir_p(:filename.basedir(:user_cache, "phx-pandoc", tmp_opts)) ||
+ freshdir_p(Path.join(System.tmp_dir!(), "phx-pandoc")) ||
+ raise "could not install pandoc. Set MIX_XGD=1 and then set XDG_CACHE_HOME to the path you want to use as cache"
- new_path = args |> List.last() |> Path.join(new_filename)
- out_path = Path.join(opts[:cd], new_path) |> Path.expand()
+ url = get_url(base_url)
+ tar = fetch_body!(url)
- if File.exists?(path) do
- args = List.replace_at(args, -1, out_path)
- "pandoc" |> System.cmd(args ++ [path], opts) |> elem(1)
+ case :erl_tar.extract({:binary, tar}, [:compressed, cwd: to_charlist(tmp_dir)]) do
+ :ok -> :ok
+ other -> raise "couldn't unpack archive: #{inspect(other)}"
+ end
+
+ bin_path = bin_path()
+ File.mkdir_p!(Path.dirname(bin_path))
+ [tmp_dir, "pandoc-" <> version, "bin", "pandoc"] |> Path.join() |> File.cp!(bin_path)
+ end
+
+ defp freshdir_p(path) do
+ with {:ok, _} <- File.rm_rf(path),
+ :ok <- File.mkdir_p(path) do
+ path
else
- File.rm(out_path)
+ _ -> nil
end
end
+
+ defp fetch_body!(url, retry \\ true) do
+ scheme = URI.parse(url).scheme
+ url = String.to_charlist(url)
+ Logger.debug("Downloading pandoc from #{url}")
+
+ {:ok, _} = Application.ensure_all_started(:inets)
+ {:ok, _} = Application.ensure_all_started(:ssl)
+
+ if proxy = proxy_for_scheme(scheme) do
+ %{host: host, port: port} = URI.parse(proxy)
+ Logger.debug("Using #{String.upcase(scheme)}_PROXY: #{proxy}")
+ set_option = if "https" == scheme, do: :https_proxy, else: :proxy
+ :httpc.set_options([{set_option, {{String.to_charlist(host), port}, []}}])
+ end
+
+ # https://erlef.github.io/security-wg/secure_coding_and_deployment_hardening/inets
+ cacertfile = cacertfile() |> String.to_charlist()
+
+ http_options =
+ [
+ ssl: [
+ verify: :verify_peer,
+ cacertfile: cacertfile,
+ depth: 2,
+ customize_hostname_check: [
+ match_fun: :public_key.pkix_verify_hostname_match_fun(:https)
+ ],
+ versions: protocol_versions()
+ ]
+ ]
+ |> maybe_add_proxy_auth(scheme)
+
+ options = [body_format: :binary]
+
+ case {retry, :httpc.request(:get, {url, []}, http_options, options)} do
+ {_, {:ok, {{_, 200, _}, _headers, body}}} ->
+ body
+
+ {true, {:error, {:failed_connect, [{:to_address, _}, {inet, _, reason}]}}}
+ when inet in [:inet, :inet6] and
+ reason in [:ehostunreach, :enetunreach, :eprotonosupport, :nxdomain] ->
+ :httpc.set_options(ipfamily: fallback(inet))
+ fetch_body!(url, false)
+
+ other ->
+ raise """
+ Couldn't fetch #{url}: #{inspect(other)}
+
+ This typically means we cannot reach the source or you are behind a proxy.
+ You can try again later and, if that does not work, you might:
+
+ 1. If behind a proxy, ensure your proxy is configured and that
+ your certificates are set via the cacerts_path configuration
+
+ 2. Manually download the executable from the URL above and
+ place it inside "_build/pandoc-#{target()}"
+ """
+ end
+ end
+
+ defp fallback(:inet), do: :inet6
+ defp fallback(:inet6), do: :inet
+
+ defp proxy_for_scheme("http") do
+ System.get_env("HTTP_PROXY") || System.get_env("http_proxy")
+ end
+
+ defp proxy_for_scheme("https") do
+ System.get_env("HTTPS_PROXY") || System.get_env("https_proxy")
+ end
+
+ defp maybe_add_proxy_auth(http_options, scheme) do
+ case proxy_auth(scheme) do
+ nil -> http_options
+ auth -> [{:proxy_auth, auth} | http_options]
+ end
+ end
+
+ defp proxy_auth(scheme) do
+ with proxy when is_binary(proxy) <- proxy_for_scheme(scheme),
+ %{userinfo: userinfo} when is_binary(userinfo) <- URI.parse(proxy),
+ [username, password] <- String.split(userinfo, ":") do
+ {String.to_charlist(username), String.to_charlist(password)}
+ else
+ _ -> nil
+ end
+ end
+
+ defp cacertfile() do
+ Application.get_env(:pandoc, :cacerts_path) || CAStore.file_path()
+ end
+
+ defp protocol_versions do
+ if otp_version() < 25, do: [:"tlsv1.2"], else: [:"tlsv1.2", :"tlsv1.3"]
+ end
+
+ defp otp_version do
+ :erlang.system_info(:otp_release) |> List.to_integer()
+ end
+
+ # Available targets: https://github.com/jgm/pandoc/releases
+ # We support only linux-amd64, for now.
+ defp target do
+ case :os.type() do
+ # Assuming it's an x86 CPU
+ {:win32, _} ->
+ raise "pandoc does not currently support OS family: Windows"
+
+ {:unix, osname} ->
+ arch_str = :erlang.system_info(:system_architecture)
+ [arch | _] = arch_str |> List.to_string() |> String.split("-")
+
+ case arch do
+ "amd64" -> "#{osname}-amd64"
+ "x86_64" -> "#{osname}-amd64"
+ _ -> raise "pandoc does not currently support architecture: #{arch_str}"
+ end
+ end
+ end
+
+ defp get_url(base_url) do
+ base_url
+ |> String.replace("$version", configured_version())
+ |> String.replace("$target", target())
+ end
end
--
cgit v1.2.3