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chore: Centralize Status Management
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Signed-off-by: gatici <gulsum.atici@canonical.com>
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@gatici
gatici committed Mar 14, 2024
1 parent db4982b commit 8f0b729
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Showing 2 changed files with 185 additions and 105 deletions.
246 changes: 165 additions & 81 deletions src/charm.py
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Original file line number Diff line number Diff line change
Expand Up @@ -19,10 +19,17 @@
generate_private_key,
)
from jinja2 import Environment, FileSystemLoader
from ops import (
ActiveStatus,
BlockedStatus,
CollectStatusEvent,
ModelError,
RelationBrokenEvent,
WaitingStatus,
)
from ops.charm import CharmBase
from ops.framework import EventBase
from ops.main import main
from ops.model import ActiveStatus, BlockedStatus, WaitingStatus
from ops.pebble import Layer

logger = logging.getLogger(__name__)
Expand All @@ -48,7 +55,7 @@ class PCFOperatorCharm(CharmBase):
def __init__(self, *args):
super().__init__(*args)
if not self.unit.is_leader():
raise NotImplementedError("Scaling is not implemented for this charm")
return
self._container_name = self._service_name = "pcf"
self._container = self.unit.get_container(self._container_name)

Expand All @@ -60,12 +67,13 @@ def __init__(self, *args):
self._certificates = TLSCertificatesRequiresV3(self, "certificates")
self._logging = LogForwarder(charm=self, relation_name=LOGGING_RELATION_NAME)
self.framework.observe(self.on.update_status, self._configure_sdcore_pcf)
self.framework.observe(self.on.collect_unit_status, self._on_collect_unit_status)
self.framework.observe(self.on.database_relation_joined, self._configure_sdcore_pcf)
self.framework.observe(self.on.database_relation_broken, self._on_database_relation_broken)
self.framework.observe(self.on.database_relation_broken, self._configure_sdcore_pcf)
self.framework.observe(self._database.on.database_created, self._configure_sdcore_pcf)
self.framework.observe(self.on.fiveg_nrf_relation_joined, self._configure_sdcore_pcf)
self.framework.observe(self._nrf_requires.on.nrf_available, self._configure_sdcore_pcf)
self.framework.observe(self._nrf_requires.on.nrf_broken, self._on_nrf_broken)
self.framework.observe(self._nrf_requires.on.nrf_broken, self._configure_sdcore_pcf)
self.framework.observe(self.on.pcf_pebble_ready, self._configure_sdcore_pcf)
self.framework.observe(self.on.certificates_relation_joined, self._configure_sdcore_pcf)
self.framework.observe(
Expand All @@ -78,66 +86,193 @@ def __init__(self, *args):
self._certificates.on.certificate_expiring, self._on_certificate_expiring
)

def _configure_sdcore_pcf(self, event: EventBase) -> None: # noqa C901
"""Adds Pebble layer and manages Juju unit status.
def _on_collect_unit_status(self, event: CollectStatusEvent): # noqa C901
"""Check the unit status and set to Unit when CollectStatusEvent is fired.
Args:
event (EventBase): Juju event.
event: CollectStatusEvent
"""
if not self.unit.is_leader():
# NOTE: In cases where leader status is lost before the charm is
# finished processing all teardown events, this prevents teardown
# event code from running. Luckily, for this charm, none of the
# teardown code is necessary to perform if we're removing the
# charm.
event.add_status(BlockedStatus("Scaling is not implemented for this charm"))
return

if not self._container.can_connect():
self.unit.status = WaitingStatus("Waiting for container to be ready")
event.add_status(WaitingStatus("Waiting for container to be ready"))
return

for relation in [DATABASE_RELATION_NAME, NRF_RELATION_NAME, TLS_RELATION_NAME]:
if not self._relation_created(relation):
self.unit.status = BlockedStatus(
f"Waiting for `{relation}` relation to be created"
)
event.add_status(BlockedStatus(f"Waiting for {relation} relation"))
return

if not self._database_is_available():
self.unit.status = WaitingStatus(
f"Waiting for `{DATABASE_RELATION_NAME}` relation to be available"
event.add_status(
WaitingStatus(f"Waiting for `{DATABASE_RELATION_NAME}` relation to be available")
)
return

if not self._nrf_is_available():
self.unit.status = WaitingStatus("Waiting for NRF endpoint to be available")
event.add_status(WaitingStatus("Waiting for NRF endpoint to be available"))
return

if not self._storage_is_attached():
self.unit.status = WaitingStatus("Waiting for the storage to be attached")
event.add_status(WaitingStatus("Waiting for the storage to be attached"))
return

if not _get_pod_ip():
event.add_status(WaitingStatus("Waiting for pod IP address to be available"))
return

if self._csr_is_stored() and not self._get_current_provider_certificate():
event.add_status(WaitingStatus("Waiting for certificates to be stored"))
return

if not self._pcf_service_is_running():
event.add_status(WaitingStatus("Waiting for PCF service to start"))
return

event.add_status(ActiveStatus())

def _pcf_service_is_running(self) -> bool:
"""Check if the PCF service is running.
Returns:
bool: Whether the PCF service is running.
"""
if not self._container.can_connect():
return False
try:
service = self._container.get_service(self._service_name)
except ModelError:
return False
return service.is_running()

def ready_to_configure(self) -> bool:
"""Returns whether the preconditions are met to proceed with the configuration.
Returns:
ready_to_configure: True if all conditions are met else False
"""
if not self._container.can_connect():
return False

for relation in [DATABASE_RELATION_NAME, NRF_RELATION_NAME, TLS_RELATION_NAME]:
if not self._relation_created(relation):
return False

if not self._database_is_available():
return False

if not self._nrf_is_available():
return False

if not self._storage_is_attached():
return False

if not _get_pod_ip():
self.unit.status = WaitingStatus("Waiting for pod IP address to be available")
return False

return True

def _configure_sdcore_pcf(self, event: EventBase) -> None:
"""Adds Pebble layer and manages Juju unit status.
Args:
event (EventBase): Juju event.
"""
if not self.ready_to_configure():
logger.info("The preconditions for the configuration are not met yet.")
return

if not self._private_key_is_stored():
self._generate_private_key()

if not self._csr_is_stored():
self._request_new_certificate()

provider_certificate = self._get_current_provider_certificate()
if not provider_certificate:
self.unit.status = WaitingStatus("Waiting for certificates to be stored")
return
certificate_changed = self._update_certificate(provider_certificate=provider_certificate)
config_file_changed = self._update_config_file()
self._configure_pebble(restart=(config_file_changed or certificate_changed))
self.unit.status = ActiveStatus()

def _on_nrf_broken(self, event: EventBase) -> None:
"""Event handler for NRF relation broken.
if certificate_update_required := self._is_certificate_update_required(
provider_certificate
):
self._store_certificate(certificate=provider_certificate)

desired_config_file = self._generate_pcf_config_file()
if config_update_required := self._is_config_update_required(desired_config_file):
self._push_config_file(content=desired_config_file)

should_restart = config_update_required or certificate_update_required
self._configure_pebble(restart=should_restart)

def _is_certificate_update_required(self, provider_certificate) -> bool:
"""Checks the provided certificate and existing certificate.
Returns True if update is required.
Args:
event (NRFBrokenEvent): Juju event
provider_certificate: str
Returns:
True if update is required else False
"""
self.unit.status = BlockedStatus("Waiting for fiveg_nrf relation")
return self._get_existing_certificate() != provider_certificate

def _on_database_relation_broken(self, event: EventBase) -> None:
"""Event handler for database relation broken.
def _get_existing_certificate(self) -> str:
"""Returns the existing certificate if present else empty string."""
return self._get_stored_certificate() if self._certificate_is_stored() else ""

def _push_config_file(
self,
content: str,
) -> None:
"""Push the PCF config file to the container.
Args:
event: Juju event
content (str): Content of the config file.
"""
self.unit.status = BlockedStatus("Waiting for database relation")
self._container.push(
path=f"{BASE_CONFIG_PATH}/{CONFIG_FILE_NAME}",
source=content,
)
logger.info("Pushed: %s to workload.", CONFIG_FILE_NAME)

def _generate_pcf_config_file(self) -> str:
"""Handles creation of the PCF config file based on a given template.
Returns:
content (str): desired config file content
"""
return self._render_config_file(
database_name=DATABASE_NAME,
database_url=self._get_database_data()["uris"].split(",")[0],
nrf_url=self._nrf_requires.nrf_url,
pcf_sbi_port=PCF_SBI_PORT,
pod_ip=_get_pod_ip(), # type: ignore[arg-type]
scheme="https",
)

def _is_config_update_required(self, content: str) -> bool:
"""Decides whether config update is required by checking existence and config content.
Args:
content (str): desired config file content
def _on_certificates_relation_broken(self, event: EventBase) -> None:
Returns:
True if config update is required else False
"""
if not self._config_file_is_written() or not self._config_file_content_matches(
content=content
):
return True
return False

def _on_certificates_relation_broken(self, event: RelationBrokenEvent) -> None:
"""Deletes TLS related artifacts and reconfigures workload.
Args:
Expand All @@ -149,7 +284,6 @@ def _on_certificates_relation_broken(self, event: EventBase) -> None:
self._delete_private_key()
self._delete_csr()
self._delete_certificate()
self.unit.status = BlockedStatus("Waiting for certificates relation")

def _get_current_provider_certificate(self) -> str | None:
"""Compares the current certificate request to what is in the interface.
Expand All @@ -162,20 +296,6 @@ def _get_current_provider_certificate(self) -> str | None:
return provider_certificate.certificate
return None

def _update_certificate(self, provider_certificate) -> bool:
"""Compares the provided certificate to what is stored.
Returns True if the certificate was updated
"""
existing_certificate = (
self._get_stored_certificate() if self._certificate_is_stored() else ""
)

if existing_certificate != provider_certificate:
self._store_certificate(certificate=provider_certificate)
return True
return False

def _on_certificate_expiring(self, event: CertificateExpiringEvent) -> None:
"""Requests new certificate.
Expand Down Expand Up @@ -284,30 +404,6 @@ def _configure_pebble(self, restart: bool = False) -> None:
return
self._container.replan()

def _update_config_file(self) -> bool:
"""Updates config file.
Writes the config file if it does not exist or
the content does not match.
Returns:
bool: True if config file was updated, False otherwise.
"""
content = self._render_config_file(
database_name=DATABASE_NAME,
database_url=self._get_database_data()["uris"].split(",")[0],
nrf_url=self._nrf_requires.nrf_url,
pcf_sbi_port=PCF_SBI_PORT,
pod_ip=_get_pod_ip(), # type: ignore[arg-type]
scheme="https",
)
if not self._config_file_is_written() or not self._config_file_content_matches(
content=content
):
self._write_config_file(content=content)
return True
return False

def _render_config_file(
self,
*,
Expand Down Expand Up @@ -340,18 +436,6 @@ def _render_config_file(
scheme=scheme,
)

def _write_config_file(self, content: str) -> None:
"""Writes config file to workload.
Args:
content (str): Config file content.
"""
self._container.push(
path=f"{BASE_CONFIG_PATH}/{CONFIG_FILE_NAME}",
source=content,
)
logger.info("Pushed: %s to workload.", CONFIG_FILE_NAME)

def _config_file_is_written(self) -> bool:
"""Returns whether the config file was written to the workload container.
Expand Down
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