From 08c8e10c2d3ae9922fe84c9bf21f9e057fbe09d7 Mon Sep 17 00:00:00 2001
From: Brendan Melville <bmelville@google.com>
Date: Tue, 3 Nov 2015 11:45:11 -0800
Subject: [PATCH] Moving replicatedservice.py to its own example to be used by
others.
---
.../replicatedservice/replicatedservice.py | 187 ++++++++++++++++++
1 file changed, 187 insertions(+)
create mode 100644 examples/replicatedservice/replicatedservice.py
diff --git a/examples/replicatedservice/replicatedservice.py b/examples/replicatedservice/replicatedservice.py
new file mode 100644
index 000000000..02c7419a2
--- /dev/null
+++ b/examples/replicatedservice/replicatedservice.py
@@ -0,0 +1,187 @@
+"""Defines a ReplicatedService type by creating both a Service and an RC.
+
+This module creates a typical abstraction for running a service in a
+Kubernetes cluster, namely a replication controller and a service packaged
+together into a single unit.
+"""
+
+import yaml
+
+SERVICE_TYPE_COLLECTION = 'Service'
+RC_TYPE_COLLECTION = 'ReplicationController'
+
+
+def GenerateConfig(context):
+ """Generates a Replication Controller and a matching Service.
+
+ Args:
+ context: Template context, which can contain the following properties:
+ container_name - Name to use for container. If omitted, name is
+ used.
+ namespace - Namespace to create the resources in. If omitted,
+ 'default' is used.
+ service_name - Name to use for service. If omitted name-service is
+ used.
+ protocol - Protocol to use for the service
+ service_port - Port to use for the service
+ target_port - Target port for the service
+ container_port - Container port to use
+ replicas - Number of replicas to create in RC
+ image - Docker image to use for replicas. Required.
+ labels - labels to apply.
+ env - Environmental variables to apply (list of maps). Format
+ should be:
+ [{'name': ENV_VAR_NAME, 'value':'ENV_VALUE'},
+ {'name': ENV_VAR_NAME_2, 'value':'ENV_VALUE_2'}]
+ external_service - If set to true, enable external Load Balancer
+
+ Returns:
+ A Container Manifest as a YAML string.
+ """
+ # YAML config that we're going to create for both RC & Service
+ config = {'resources': []}
+
+ name = context.env['name']
+ container_name = context.properties.get('container_name', name)
+ namespace = context.properties.get('namespace', 'default')
+
+ # Define things that the Service cares about
+ service_name = context.properties.get('service_name', name + '-service')
+ service_type = SERVICE_TYPE_COLLECTION
+
+ # Define things that the Replication Controller (rc) cares about
+ rc_name = name + '-rc'
+ rc_type = RC_TYPE_COLLECTION
+
+ service = {
+ 'name': service_name,
+ 'type': service_type,
+ 'properties': {
+ 'apiVersion': 'v1',
+ 'kind': 'Service',
+ 'namespace': namespace,
+ 'metadata': {
+ 'name': service_name,
+ 'labels': GenerateLabels(context, service_name),
+ },
+ 'spec': {
+ 'ports': [GenerateServicePorts(context, container_name)],
+ 'selector': GenerateLabels(context, name)
+ }
+ }
+ }
+ set_up_external_lb = context.properties.get('external_service', None)
+ if set_up_external_lb:
+ service['properties']['spec']['type'] = 'LoadBalancer'
+ config['resources'].append(service)
+
+ rc = {
+ 'name': rc_name,
+ 'type': rc_type,
+ 'properties': {
+ 'apiVersion': 'v1',
+ 'kind': 'ReplicationController',
+ 'namespace': namespace,
+ 'metadata': {
+ 'name': rc_name,
+ 'labels': GenerateLabels(context, rc_name),
+ },
+ 'spec': {
+ 'replicas': context.properties['replicas'],
+ 'selector': GenerateLabels(context, name),
+ 'template': {
+ 'metadata': {
+ 'labels': GenerateLabels(context, name),
+ },
+ 'spec': {
+ 'containers': [
+ {
+ 'env': GenerateEnv(context),
+ 'name': container_name,
+ 'image': context.properties['image'],
+ 'ports': [
+ {
+ 'name': container_name,
+ 'containerPort': context.properties['container_port'],
+ }
+ ]
+ }
+ ]
+ }
+ }
+ }
+ }
+ }
+
+ config['resources'].append(rc)
+ return yaml.dump(config)
+
+
+# Generates labels either from the context.properties['labels'] or generates
+# a default label 'name':name
+def GenerateLabels(context, name):
+ """Generates labels from context.properties['labels'] or creates default.
+
+ We make a deep copy of the context.properties['labels'] section to avoid
+ linking in the yaml document, which I believe reduces readability of the
+ expanded template. If no labels are given, generate a default 'name':name.
+
+ Args:
+ context: Template context, which can contain the following properties:
+ labels - Labels to generate
+
+ Returns:
+ A dict containing labels in a name:value format
+ """
+ tmp_labels = context.properties.get('labels', None)
+ ret_labels = {'name': name}
+ if isinstance(tmp_labels, dict):
+ for key, value in tmp_labels.iteritems():
+ ret_labels[key] = value
+ return ret_labels
+
+
+def GenerateServicePorts(context, name):
+ """Generates a ports section for a service.
+
+ Args:
+ context: Template context, which can contain the following properties:
+ service_port - Port to use for the service
+ target_port - Target port for the service
+ protocol - Protocol to use.
+
+ Returns:
+ A dict containing a port definition
+ """
+ service_port = context.properties.get('service_port', None)
+ target_port = context.properties.get('target_port', None)
+ protocol = context.properties.get('protocol')
+
+ ports = {}
+ if name:
+ ports['name'] = name
+ if service_port:
+ ports['port'] = service_port
+ if target_port:
+ ports['targetPort'] = target_port
+ if protocol:
+ ports['protocol'] = protocol
+
+ return ports
+
+def GenerateEnv(context):
+ """Generates environmental variables for a pod.
+
+ Args:
+ context: Template context, which can contain the following properties:
+ env - Environment variables to set.
+
+ Returns:
+ A list containing env variables in dict format {name: 'name', value: 'value'}
+ """
+ env = []
+ tmp_env = context.properties.get('env', [])
+ for entry in tmp_env:
+ if isinstance(entry, dict):
+ env.append({'name': entry.get('name'), 'value': entry.get('value')})
+ return env
--
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