From fd31d0bd32886ca4075d4938e374c5c7d72c9b8c Mon Sep 17 00:00:00 2001 From: Tom Hughes Date: Sun, 16 Oct 2016 10:14:57 +0100 Subject: [PATCH] Make map export report an error on resource exhaustion --- cookbooks/tile/templates/default/export.erb | 90 ++++++++++++--------- 1 file changed, 51 insertions(+), 39 deletions(-) diff --git a/cookbooks/tile/templates/default/export.erb b/cookbooks/tile/templates/default/export.erb index 97aa161f6..dfd076252 100644 --- a/cookbooks/tile/templates/default/export.erb +++ b/cookbooks/tile/templates/default/export.erb @@ -9,6 +9,7 @@ import shutil import sys import tempfile import resource +import signal # Limit maximum CPU time # The Postscript output format can sometimes take hours @@ -37,7 +38,8 @@ def file_size(file): return os.fstat(file.fileno()).st_size # Routine to report an error -def output_error(message): +def output_error(message, status = "400 Bad Request"): + print "Status: %s" % status output_headers("text/html") print "" print "" @@ -63,13 +65,11 @@ idletime = cputimes[3] / sum(cputimes) # Process the request if idletime < 0.2: # Abort if the CPU idle time on the machine is too low - print "Status: 503 Service Unavailable" - output_error("The server is too busy at the moment. Please wait a few minutes before trying again.") + output_error("The server is too busy at the moment. Please wait a few minutes before trying again.", "503 Service Unavailable") <% @blocks["user_agents"].each do |user_agent| -%> elif os.environ['HTTP_USER_AGENT'] == '<%= user_agent %>': # Block scraper - print "Status: 503 Service Unavailable" - output_error("The server is too busy at the moment. Please wait a few minutes before trying again.") + output_error("The server is too busy at the moment. Please wait a few minutes before trying again.", "503 Service Unavailable") <% end -%> elif not form.has_key("bbox"): # No bounding box specified @@ -116,39 +116,51 @@ else: # Zoom the map to the bounding box map.zoom_to_box(bbox) + # Fork so that we can handle crashes rendering the map + pid = os.fork() + # Render the map - if form.getvalue("format") == "png": - image = mapnik.Image(map.width, map.height) - mapnik.render(map, image) - png = image.tostring("png") - output_headers("image/png", "map.png", len(png)) - sys.stdout.write(png) - elif form.getvalue("format") == "jpeg": - image = mapnik.Image(map.width, map.height) - mapnik.render(map, image) - jpeg = image.tostring("jpeg") - output_headers("image/jpeg", "map.jpg", len(jpeg)) - sys.stdout.write(jpeg) - elif form.getvalue("format") == "svg": - file = tempfile.NamedTemporaryFile(prefix = "export") - surface = cairo.SVGSurface(file.name, map.width, map.height) - mapnik.render(map, surface) - surface.finish() - output_headers("image/svg+xml", "map.svg", file_size(file)) - output_file(file) - elif form.getvalue("format") == "pdf": - file = tempfile.NamedTemporaryFile(prefix = "export") - surface = cairo.PDFSurface(file.name, map.width, map.height) - mapnik.render(map, surface) - surface.finish() - output_headers("application/pdf", "map.pdf", file_size(file)) - output_file(file) - elif form.getvalue("format") == "ps": - file = tempfile.NamedTemporaryFile(prefix = "export") - surface = cairo.PSSurface(file.name, map.width, map.height) - mapnik.render(map, surface) - surface.finish() - output_headers("application/postscript", "map.ps", file_size(file)) - output_file(file) + if pid == 0: + if form.getvalue("format") == "png": + image = mapnik.Image(map.width, map.height) + mapnik.render(map, image) + png = image.tostring("png") + output_headers("image/png", "map.png", len(png)) + sys.stdout.write(png) + elif form.getvalue("format") == "jpeg": + image = mapnik.Image(map.width, map.height) + mapnik.render(map, image) + jpeg = image.tostring("jpeg") + output_headers("image/jpeg", "map.jpg", len(jpeg)) + sys.stdout.write(jpeg) + elif form.getvalue("format") == "svg": + file = tempfile.NamedTemporaryFile(prefix = "export") + surface = cairo.SVGSurface(file.name, map.width, map.height) + mapnik.render(map, surface) + surface.finish() + output_headers("image/svg+xml", "map.svg", file_size(file)) + output_file(file) + elif form.getvalue("format") == "pdf": + file = tempfile.NamedTemporaryFile(prefix = "export") + surface = cairo.PDFSurface(file.name, map.width, map.height) + mapnik.render(map, surface) + surface.finish() + output_headers("application/pdf", "map.pdf", file_size(file)) + output_file(file) + elif form.getvalue("format") == "ps": + file = tempfile.NamedTemporaryFile(prefix = "export") + surface = cairo.PSSurface(file.name, map.width, map.height) + mapnik.render(map, surface) + surface.finish() + output_headers("application/postscript", "map.ps", file_size(file)) + output_file(file) + else: + output_error("Unknown format '%s'" % form.getvalue("format")) else: - output_error("Unknown format '%s'" % form.getvalue("format")) + pid, status = os.waitpid(pid, 0) + if status & 0xff == signal.SIGXCPU: + output_error("CPU time limit exceeded", "509 Resource Limit Exceeded") + elif status & 0xff == signal.SIGSEGV: + output_error("Memory limit exceeded", "509 Resource Limit Exceeded") + elif status != 0: + output_error("Internal server error", "500 Internal Server Error") -- 2.43.2