Add Pleroma.Utils.command_available?/1 and use where appropriate

lib/pleroma/upload/filter/exiftool.ex

@@ -9,8 +9,15 @@ defmodule Pleroma.Upload.Filter.Exiftool do
   """
   @behaviour Pleroma.Upload.Filter
 
+  require Logger
+
   def filter(%Pleroma.Upload{tempfile: file, content_type: "image" <> _}) do
-    System.cmd("exiftool", ["-overwrite_original", "-gps:all=", file], parallelism: true)
+    if Pleroma.Utils.command_available?("exiftool") do
+      System.cmd("exiftool", ["-overwrite_original", "-gps:all=", file], parallelism: true)
+    else
+      Logger.warn("exiftool is not available, filter #{__MODULE__} skipped")
+    end
+
     :ok
   end
 

lib/pleroma/utils.ex

@@ -9,4 +9,19 @@ defmodule Pleroma.Utils do
     |> Enum.map(&Path.join(dir, &1))
     |> Kernel.ParallelCompiler.compile()
   end
+
+  @doc """
+  POSIX-compliant check if command is available in the system
+
+  ## Examples
+      iex> command_available?("git")
+      true
+      iex> command_available?("wrongcmd")
+      false
+
+  """
+  @spec command_available?(String.t()) :: boolean()
+  def command_available?(command) do
+    match?({_output, 0}, System.cmd("sh", ["-c", "command -v #{command}"]))
+  end
 end

mix.exs

@@ -234,10 +234,10 @@ defmodule Pleroma.Mixfile do
   defp version(version) do
     identifier_filter = ~r/[^0-9a-z\-]+/i
 
-    {_cmdgit, cmdgit_err} = System.cmd("sh", ["-c", "command -v git"])
+    git_available? = Pleroma.Utils.command_available?("git")
 
     git_pre_release =
-      if cmdgit_err == 0 do
+      if git_available? do
         {tag, tag_err} =
           System.cmd("git", ["describe", "--tags", "--abbrev=0"], stderr_to_stdout: true)
 
@@ -263,7 +263,7 @@ defmodule Pleroma.Mixfile do
 
     # Branch name as pre-release version component, denoted with a dot
     branch_name =
-      with 0 <- cmdgit_err,
+      with true <- git_available?,
            {branch_name, 0} <- System.cmd("git", ["rev-parse", "--abbrev-ref", "HEAD"]),
            branch_name <- String.trim(branch_name),
            branch_name <- System.get_env("PLEROMA_BUILD_BRANCH") || branch_name,

test/upload/filter/exiftool_test.exs

@@ -7,6 +7,8 @@ defmodule Pleroma.Upload.Filter.ExiftoolTest do
   alias Pleroma.Upload.Filter
 
   test "apply exiftool filter" do
+    assert Pleroma.Utils.command_available?("exiftool")
+
     File.cp!(
       "test/fixtures/DSCN0010.jpg",
       "test/fixtures/DSCN0010_tmp.jpg"