cleanup + refactoring

.gitignore

@@ -11,4 +11,4 @@ __pycache__/
 *.egg-info/
 */*.rock
 */*.snap
-*/*.charm
+

jenkins_agent_snap/commands/agent.start

@@ -3,41 +3,62 @@
 # Copyright 2023 Canonical Ltd.
 # See LICENSE file for licensing details.
 
+err() {
+  echo "[$(date +'%Y-%m-%dT%H:%M:%S%z')]: $*" >&2
+}
+
+info() {
+   echo "[$(date +'%Y-%m-%dT%H:%M:%S%z')]: $*"
+}
+
+stop() {
+    snapctl stop jenkins-agent
+    exit 1
+}
+
 set -eu -o pipefail
 
 export LC_ALL=C
 export TERM=xterm
 
 . "$SNAP/bin/management"
-# defaults for jenkins-agent component of the jenkins continuous integration
-# system
-
-# Setup
-echo "JAVA_HOME : $JAVA_HOME"
-echo "snap run user: $(whoami)"
-WORKDIR=$(pwd)
-echo "snap workdir: ${SNAP}, current dir: ${WORKDIR}"
-which java || echo "java not found, exiting"
-echo "Fetching environment variables"
-# URL of jenkins server to connect to
-# Not specifying this parameter will stop the agent
-# job from running.
-jenkins_url="$(jenkins_url)"
-typeset JENKINS_URL="${jenkins_url:?"URL of a jenkins server must be provided"}"
-# Agent
-jenkins_agent="$(jenkins_agent)"
-typeset JENKINS_AGENT="${jenkins_agent:?"Jenkins agent name must be provided"}"
-# Token
-jenkins_token="$(jenkins_token)"
-typeset JENKINS_TOKEN="${jenkins_token:?"Jenkins agent token must be provided"}"
-# Download the agent.jar
-echo "Downloading agent binary"
-curl -sO "${JENKINS_URL}/jnlpJars/agent.jar"
-# Inspect
-ls -la agent.jar
+
+readonly JENKINS_HOME="/var/lib/jenkins"
+if ! mkdir -p $JENKINS_HOME; then
+    err "Error initializing the agent's home directory"
+    stop
+fi
+cd $JENKINS_HOME
+
+# fetch snap configuration
+JENKINS_URL="$(jenkins_url)"
+JENKINS_AGENT="$(jenkins_agent)"
+JENKINS_TOKEN="$(jenkins_token)"
+
+if [[ "${JENKINS_URL}" == "unset" || "${JENKINS_AGENT}" == "unset" || "${JENKINS_TOKEN}" == "unset" ]]; then
+    if [[ "${JENKINS_URL}" == "unset" ]]; then
+        err "JENKINS_URL needs to be configured"
+    fi
+    if [[ "${JENKINS_AGENT}" == "unset" ]]; then
+        err "JENKINS_AGENT needs to be configured"
+    fi
+    if [[ "${JENKINS_TOKEN}" == "unset" ]]; then
+        err "JENKINS_TOKEN needs to be configured"
+    fi
+    err "Invalid configuration, missing value(s)"
+    stop
+fi
+
+if ! curl "${JENKINS_URL}/jnlpJars/agent.jar" -o ${JENKINS_HOME}/agent.jar; then
+    err Unable to download agent binary
+    stop
+fi
+
 # Specify the agent as ready
-touch $WORKDIR/.ready
-# Start Jenkins agent
-java -jar agent.jar -jnlpUrl "${JENKINS_URL}/computer/${JENKINS_AGENT}/slave-agent.jnlp" -workDir "${WORKDIR}" -noReconnect -secret "${JENKINS_TOKEN}" || echo "Invalid or already used credentials."
-# Remove ready mark if unsuccessful
-rm $WORKDIR/.ready
+touch $JENKINS_HOME/.ready
+if ! java -jar agent.jar -jnlpUrl "${JENKINS_URL}/computer/${JENKINS_AGENT}/slave-agent.jnlp" -workDir "${JENKINS_HOME}" -noReconnect -secret "${JENKINS_TOKEN}"; then
+    err "Error connecting to jenkins"
+    # Remove ready mark if unsuccessful
+    rm $JENKINS_HOME/.ready
+    stop
+fi

jenkins_agent_snap/hooks/configure

@@ -53,4 +53,4 @@ handle_jenkins_token_config()
 
 handle_jenkins_url_config
 handle_jenkins_agent_config
-handle_jenkins_token_config
+handle_jenkins_token_config

jenkins_agent_snap/scripts/management

@@ -40,4 +40,4 @@ jenkins_token()
 set_jenkins_token()
 {
     snapctl set jenkins.token="$1"
-}
+}

jenkins_agent_snap/snapcraft.yaml

@@ -22,9 +22,6 @@ parts:
     stage-snaps:
       - openjdk
     plugin: dump
-    override-prime: |
-      snapcraftctl prime
-      ls -la $SNAPCRAFT_PRIME
     source: commands
     organize:
       '*': bin/
@@ -46,12 +43,6 @@ parts:
     stage-packages:
       - curl
       - git
-    # stage-snaps:
-    #   - charmcraft
-    #   - juju
-    #   - rockcraft
-    #   - lxd
-    #   - snapcraft
     stage:
       - -etc/bash_completion.d
       - -etc/cron.d

requirements.txt

@@ -1 +1,3 @@
-ops >= 2.2.0
+ops>=2,<3
+requests>=2,<3
+pydantic>=1,<2

src/charm.py

@@ -35,87 +35,28 @@ def __init__(self, *args: typing.Any):
             self.unit.status = ops.BlockedStatus(exc.msg)
             return
 
-        self.pebble_service = service.Service(self.state)
         self.agent_observer = agent_observer.Observer(self, self.state, self.pebble_service)
 
         self.framework.observe(self.on.config_changed, self._on_config_changed)
         self.framework.observe(self.on.upgrade_charm, self._on_upgrade_charm)
 
-    def _register_via_config(
-        self, event: typing.Union[ops.ConfigChangedEvent, ops.UpgradeCharmEvent]
-    ) -> None:
-        """Register the agent to server from configuration values.
-
-        Args:
-            event: The event fired on config changed or upgrade charm.
-
-        Raises:
-            RuntimeError: if the Jenkins agent failed to download.
-        """
-        container = self.unit.get_container(self.state.jenkins_agent_service_name)
-        if not container.can_connect():
-            logger.warning("Jenkins agent container not yet ready. Deferring.")
-            event.defer()
-            return
-
-        if (
-            not self.state.jenkins_config
-            and not self.model.get_relation(AGENT_RELATION)
-        ):
-            self.model.unit.status = ops.BlockedStatus("Waiting for config/relation.")
-            return
-
-        if not self.state.jenkins_config:
-            # Support fallback relation to AGENT_RELATION.
-            self.model.unit.status = ops.BlockedStatus(
-                "Please remove and re-relate agent relation."
-            )
-            return
-
-        try:
-            server.download_jenkins_agent(
-                server_url=self.state.jenkins_config.server_url,
-                container=container,
-            )
-        except server.AgentJarDownloadError as exc:
-            logger.error("Failed to download Agent JAR executable, %s", exc)
-            raise RuntimeError("Failed to download Jenkins agent. Fix issue ") from exc
-
-        valid_agent_token = server.find_valid_credentials(
-            agent_name_token_pairs=self.state.jenkins_config.agent_name_token_pairs,
-            server_url=self.state.jenkins_config.server_url,
-            container=container,
-        )
-        if not valid_agent_token:
-            logger.error("No valid agent-token pair found.")
-            self.model.unit.status = ops.BlockedStatus(
-                "Additional valid agent-token pairs required."
-            )
-            return
-
-        self.model.unit.status = ops.MaintenanceStatus("Starting agent pebble service.")
-        self.pebble_service.reconcile(
-            server_url=self.state.jenkins_config.server_url,
-            agent_token_pair=valid_agent_token,
-            container=container,
-        )
-        self.model.unit.status = ops.ActiveStatus()
-
     def _on_config_changed(self, event: ops.ConfigChangedEvent) -> None:
         """Handle config changed event.
 
         Args:
             event: The event fired on configuration change.
         """
-        self._register_via_config(event)
+        # TODO: implement lifecycle management with snap
+        self._reconcile(event)
 
     def _on_upgrade_charm(self, event: ops.UpgradeCharmEvent) -> None:
         """Handle upgrade charm event.
 
         Args:
             event: The event fired on upgrade charm.
         """
-        self._register_via_config(event)
+        # TODO: implement lifecycle management with snap
+        self._reconcile(event)
 
 
 if __name__ == "__main__":  # pragma: no cover

src/charm_state.py

@@ -36,40 +36,6 @@ def __init__(self, msg: str = ""):
         self.msg = msg
 
 
-class JenkinsConfig(BaseModel):
-    """The Jenkins config from juju config values.
-
-    Attrs:
-        server_url: The Jenkins server url.
-        agent_name_token_pairs: Jenkins agent names paired with corresponding token value.
-    """
-
-    server_url: str = Field(..., min_length=1)
-    agent_name_token_pairs: typing.List[typing.Tuple[str, str]] = Field(..., min_items=1)
-
-    @classmethod
-    def from_charm_config(cls, config: ops.ConfigData) -> typing.Optional["JenkinsConfig"]:
-        """Instantiate JenkinsConfig from charm config.
-
-        Args:
-            config: Charm configuration data.
-
-        Returns:
-            JenkinsConfig if configuration exists, None otherwise.
-        """
-        server_url = config.get("jenkins_url")
-        agent_name_config = config.get("jenkins_agent_name")
-        agent_token_config = config.get("jenkins_agent_token")
-        # None represents an unset Jenkins configuration values, meaning configuration values from
-        # relation would be used.
-        if not server_url and not agent_name_config and not agent_token_config:
-            return None
-        agent_names = agent_name_config.split(":") if agent_name_config else []
-        agent_tokens = agent_token_config.split(":") if agent_token_config else []
-        agent_name_token_pairs = list(zip(agent_names, agent_tokens))
-        return cls(server_url=server_url or "", agent_name_token_pairs=agent_name_token_pairs)
-
-
 def _get_jenkins_unit(
     all_units: typing.Set[ops.Unit], current_app_name: str
 ) -> typing.Optional[ops.Unit]:
@@ -123,7 +89,6 @@ class State:
     """
 
     agent_meta: metadata.Agent
-    jenkins_config: typing.Optional[JenkinsConfig]
     agent_relation_credentials: typing.Optional[server.Credentials]
     jenkins_agent_service_name: str = "jenkins-agent"
 
@@ -150,12 +115,6 @@ def from_charm(cls, charm: ops.CharmBase) -> "State":
             logging.error("Invalid executor state, %s", exc)
             raise InvalidStateError("Invalid executor state.") from exc
 
-        try:
-            jenkins_config = JenkinsConfig.from_charm_config(charm.config)
-        except ValidationError as exc:
-            logging.error("Invalid jenkins config values, %s", exc)
-            raise InvalidStateError("Invalid jenkins config values.") from exc
-
         agent_relation = charm.model.get_relation(AGENT_RELATION)
         agent_relation_credentials: typing.Optional[server.Credentials] = None
         if agent_relation and (
@@ -167,6 +126,5 @@ def from_charm(cls, charm: ops.CharmBase) -> "State":
 
         return cls(
             agent_meta=agent_meta,
-            jenkins_config=jenkins_config,
             agent_relation_credentials=agent_relation_credentials,
         )

src/server.py

@@ -4,13 +4,10 @@
 """Functions to interact with jenkins server."""
 
 import logging
-import random
-import time
 import typing
 from pathlib import Path
 
 import ops
-import requests
 from pydantic import BaseModel
 
 logger = logging.getLogger(__name__)
@@ -39,37 +36,10 @@ class ServerBaseError(Exception):
     """Represents errors with interacting with Jenkins server."""
 
 
-class AgentJarDownloadError(ServerBaseError):
-    """Represents an error downloading agent JAR executable."""
-
-
-def download_jenkins_agent(server_url: str, container: ops.Container) -> None:
-    """Download Jenkins agent JAR executable from server.
-
-    Args:
-        server_url: The Jenkins server URL address.
-        container: The agent workload container.
-
-    Raises:
-        AgentJarDownloadError: If an error occurred downloading the JAR executable.
-    """
-    try:
-        res = requests.get(f"{server_url}/jnlpJars/agent.jar", timeout=300)
-        res.raise_for_status()
-    except (requests.HTTPError, requests.Timeout, requests.ConnectionError) as exc:
-        logger.error("Failed to download agent JAR executable from server, %s", exc)
-        raise AgentJarDownloadError(
-            "Failed to download agent JAR executable from server."
-        ) from exc
-
-    container.push(path=AGENT_JAR_PATH, make_dirs=True, source=res.content, user=USER)
-
-
 def validate_credentials(
     agent_name: str,
     credentials: Credentials,
     container: ops.Container,
-    add_random_delay: bool = False,
 ) -> bool:
     """Check if the credentials can be used to register to the server.
 
@@ -83,10 +53,6 @@ def validate_credentials(
     Returns:
         True if credentials and agent_name pairs are valid, False otherwise.
     """
-    # IMPORTANT: add random delay to prevent parallel execution.
-    if add_random_delay:
-        # It's okay to use random since it's not used for sensitive data.
-        time.sleep(random.random())  # nosec
     proc: ops.pebble.ExecProcess = container.exec(
         [
             "java",