def main(_args: Sequence[str]) -> int:
"""Main program."""
config = create_configuration()
if not config.is_valid():
warning("Configuration is invalid. Cannot start.")
return 1
generator = create_generator(config)
envoy = create_envoy_handler(config)
while True:
if os.path.exists(config.trigger_stop_file):
warning("Stopping due to existence of stop trigger file.")
envoy.stop_envoy()
return 0
debug('Generating envoy files.')
res = generator.generate_file(config.envoy_listen_port,
config.envoy_admin_port)
if os.path.isfile(config.envoy_config_file):
debug('Starting envoy.')
envoy.start_if_not_running()
if res != 0:
warning("Envoy configuration generator returned {code}", code=res)
if config.exit_on_generation_failure:
warning("Stopping due to exit-on-failure.")
envoy.stop_envoy()
return res
time.sleep(config.failure_sleep)
else:
time.sleep(config.refresh_time)
def push_template(config: Config) -> int:
"""Push a piece of the template into the templates document."""
if not config.purpose:
log.warning(
'When pushing a template, the `purpose` argument is required.')
return 3
if config.filename == '-':
source_data = sys.stdin.read()
elif not config.filename or not os.path.isfile(config.filename):
log.warning('No such local file `{file}`', file=config.filename)
return 4
else:
with open(config.filename, 'r') as f:
source_data = f.read()
log.debug("Pulling current templates")
templates = pull_document(
config, TEMPLATES_DOCUMENT) or create_initial_templates_document()
if config.category == 'gateway':
update_gateway_template(templates, source_data, config.namespace,
config.purpose)
elif config.category == 'service':
update_service_template(
templates,
source_data,
config.namespace,
config.service,
config.color,
config.purpose,
)
else:
log.warning('Unknown or unset category `{cat}`', cat=config.category)
return 5
push_document(config, TEMPLATES_DOCUMENT, templates)
return 0
def get_templates(self) -> Dict[str, str]:
"""Get the right templates for this mode (purpose -> template)."""
log.debug("Fetching templates")
all_templates = self._data_store.fetch_document('templates')
default_templates: Dict[str, str] = {}
namespace_templates: Dict[str, str] = {}
for gateway_template in all_templates['gateway-templates']:
namespace = gateway_template['namespace']
purpose = gateway_template['purpose']
if namespace == self._config.namespace:
namespace_templates[purpose] = gateway_template['template']
elif namespace == TEMPLATE_DEFAULT:
default_templates[purpose] = gateway_template['template']
return namespace_templates or default_templates
def main(_args: Sequence[str]) -> int:
"""Main program."""
config = create_configuration()
generator = create_generator(config)
while True:
if os.path.exists(config.trigger_stop_file):
warning("Stopping due to existence of stop trigger file.")
return 0
debug('Generating new discovery map.')
res = generator.update_discovery_map()
if res != 0:
warning("Envoy configuration generator returned {code}", code=res)
if config.exit_on_generation_failure:
warning("Stopping due to exit-on-failure.")
return res
time.sleep(config.failure_sleep)
else:
time.sleep(config.refresh_time)
def generate_envoy_file(config: Config, file_name: str, contents: str) -> None:
"""Performs the correct construction of the envoy file. To properly support
envoy dynamic configurations, the file must be created in a temporary file, then
replaced via a *move* operation. Due to potential issues around move, the source
file must be in the same directory as the target file (due to cross-file system
move issues)."""
# Note: this is a bit memory heavy, with the contents of source and target present
# at the same time.
out_dir = config.envoy_config_dir
target_file = os.path.join(out_dir, file_name)
# First, check if the file needs to be updated. That means the contents are different.
if os.path.isfile(target_file):
with open(target_file, 'r') as f:
current_contents = f.read()
if current_contents == contents:
log.debug(
"Contents of {file_name} are the same; not updating.",
file_name=file_name)
return
gen_fd, gen_filename = tempfile.mkstemp(prefix=file_name,
dir=out_dir,
text=False)
os.write(gen_fd, contents.encode('utf-8', errors='replace'))
os.close(gen_fd)
os.replace(gen_filename, target_file)
log.log('INFO',
"Generated configuration file {file_name}",
file_name=file_name)
log.debug('. . . . . . . . . . . . . . . . . .')
log.debug_raw(contents)
log.debug('. . . . . . . . . . . . . . . . . .')
def generate_file(self, listen_port: int, admin_port: int) -> int:
"""Runs the generation process."""
try:
log.debug("Fetching discovery map")
discovery_map = self._discovery_map.get_mesh()
mapping = create_gateway_proxy_input(
discovery_map,
self._config.namespace,
listen_port,
admin_port,
)
if isinstance(mapping, int):
log.warning("Could not create mapping.")
return mapping
for purpose, template in self.get_templates().items():
log.debug("Rendering template {purpose}", purpose=purpose)
rendered = pystache.render(template, mapping)
generate_envoy_file(self._config, purpose, rendered)
return 0
except (ExtensionPointRuntimeError,
ExtensionPointTooManyRetries) as err:
print("[nightjar-standalone] File construction generated error: " +
repr(err))
return 1
def start_if_not_running(self) -> None:
"""Start envoy if it is not running."""
if not self.is_alive():
debug('Starting {cmd}', cmd=self._config.envoy_cmd)
self._proc = subprocess.Popen(self._cmd_args())