Add compress_trace(); a helper method for compressing traces (#31)

* Add `compress_trace()`; a helper method for compressing traces

* Fix tests

src/BugReporting.jl

@@ -95,6 +95,25 @@ function rr_pack(trace_directory)
     end
 end
 
+# Helper function to compress a trace into a `.tar.zst` file
+function compress_trace(trace_directory::String, output_file::String)
+    # Ensure it's packed
+    rr_pack(trace_directory)
+
+    # Start up our `zstdmt` process to write out to that file
+    proc = zstdmt() do zstdp
+        open(`$(zstdp) - -o $(output_file)`, "r+")
+    end
+
+    # Feed the tarball into that waiting process
+    Tar.create(trace_directory, proc)
+
+    # Ensure everything closes nicely
+    close(proc.in)
+    wait(proc)
+    return nothing
+end
+
 function rr_record(args...; trace_dir=nothing)
     check_rr_available()
     check_perf_event_paranoid()

test/rr.jl

@@ -43,24 +43,35 @@ using BugReporting, Test, Pkg
         trace_files = readdir(joinpath(temp_trace_dir,"latest-trace"))
         @test !isempty(filter(f -> startswith(f, "mmap_pack_"), trace_files))
 
-        # Test that we can replay that trace: (just send in `continue` immediately to let it run)
-        new_stdout_rd, new_stdout_wr = Base.redirect_stdout()
-        new_stderr_rd, new_stderr_wr = Base.redirect_stderr()
-        new_stdin_rd, new_stdin_wr = Base.redirect_stdin()
-        write(new_stdin_wr, "continue\nquit\ny")
-        BugReporting.rr_replay(temp_trace_dir)
-        Base.redirect_stdout(old_stdout)
-        Base.redirect_stderr(old_stderr)
-        Base.redirect_stdin(old_stdin)
-        close(new_stdout_wr)
-        close(new_stderr_wr)
-        close(new_stdin_rd)
-
-        rr_stdout = String(read(new_stdout_rd))
-        rr_stderr = String(read(new_stderr_rd))
+        # Test that we can compress that trace directory
+        mktempdir() do temp_out_dir
+            tarzst_path = joinpath(temp_out_dir, "trace.tar.zst")
+            BugReporting.compress_trace(temp_trace_dir, tarzst_path)
+            @test isfile(tarzst_path)
+        end
 
-        # Test that Julia spat out what we expect, still.
-        @test occursin(msg, rr_stdout)
-        @test isempty(rr_stderr)
+        # Redirect `HOME` to a directory that we know doesn't contain a `.gdbinit` file,
+        # as that can screw up the `isempty(rr_stderr)` test below
+        withenv("HOME" => temp_trace_dir) do
+            # Test that we can replay that trace: (just send in `continue` immediately to let it run)
+            new_stdout_rd, new_stdout_wr = Base.redirect_stdout()
+            new_stderr_rd, new_stderr_wr = Base.redirect_stderr()
+            new_stdin_rd, new_stdin_wr = Base.redirect_stdin()
+            write(new_stdin_wr, "continue\nquit\ny")
+            BugReporting.replay(temp_trace_dir)
+            Base.redirect_stdout(old_stdout)
+            Base.redirect_stderr(old_stderr)
+            Base.redirect_stdin(old_stdin)
+            close(new_stdout_wr)
+            close(new_stderr_wr)
+            close(new_stdin_rd)
+
+            rr_stdout = String(read(new_stdout_rd))
+            rr_stderr = String(read(new_stderr_rd))
+
+            # Test that Julia spat out what we expect, still.
+            @test occursin(msg, rr_stdout)
+            @test isempty(rr_stderr)
+        end
     end
 end