Initial project

.gitignore

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+/.idea/
+/.DS_store

Dockerfile

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+FROM ubuntu:16.04
+
+WORKDIR /code
+
+RUN apt-get update && \
+    apt-get install -y apt-transport-https curl python3-dev nginx && \
+    curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add - && \
+    touch /etc/apt/sources.list.d/kubernetes.list && \
+    echo "deb http://apt.kubernetes.io/ kubernetes-xenial main" | tee -a /etc/apt/sources.list.d/kubernetes.list && \
+    apt-get update && \
+    apt-get install -y kubectl=1.11.1-00
+
+COPY . /code
+
+RUN chmod +x map_services.py entrypoint.sh
+
+ENTRYPOINT sh entrypoint.sh

README.md

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+# Kubernetes port forward utility
+
+> When developing services locally, we sometimes require dependant services to be proxied from our cluster to our local machine to ease development.
+> This image serves the purpose of easing that process.
+
+### Usage
+
+The image uses the environment variable $SERVICES to see which services you need proxied.
+
+This variable should contain a comma-delimited list of deployments & ports to forward
+
+The format for this variable is DEPLOYMENT_NAME:PORT:TARGET_PORT, OTHER_DEPLOYMENT:PORT:TARGET_PORT etc.
+
+TARGET_PORT is optional. If none is supplied the image will use PORT as both remote and local port.
+
+In your docker-compose file you can simply add:
+```yaml
+kube-forwards:
+    image: chris-cmsoft/kube_forward:1.0.2
+    environment:
+      - SERVICES=someservice:8000, someotherservice:8001:8000
+    volumes:
+      - ~/.kube/config:/root/.kube/config
+some-service:
+    image: some-image:1.0
+```
+
+Now if you exec into the some-service container you can curl http://kube-forwards:8000 and it will hit someservice on the Kubernetes cluster.
+

docker-compose.yml

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+version: '2'
+
+services:
+  kube_forwards:
+    build: .
+    entrypoint: ['tail', '-f', '/dev/null']
+    environment:
+      - SERVICES=authenticationservice:8000, srservice:8001:8000
+    ports:
+      - 8011:8000
+      - 8012:8001
+    volumes:
+      - ~/.kube/config:/root/.kube/config
+      - .:/code
+    networks:
+      - default
+
+networks:
+  default:

entrypoint.sh

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+#!/usr/bin/env bash
+
+python3 map_services.py && tail -f port-log.txt

map_services.py

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+#!/usr/bin/env python3
+
+"""
+Library to find deployments that need to be proxied
+
+options: (To be specified as environment variables)
+
+        SERVICES: The deployments that need to be proxied
+
+                This script will look for the first running container and proxy that through to the machine.
+"""
+
+import os
+import logging
+from subprocess import run, PIPE, Popen
+
+
+nginx_directives = ''
+
+def validate_service_spec(service_spec):
+    """
+    Valid service entries are services with:
+            * A deployment name
+            * At least one port
+
+    Allowed additions:
+            * second port for local machine
+    """
+    service_parts = service_spec.strip().split(':')
+
+    # There have to be at least two parts to the string
+    if len(service_parts) <= 1:
+        logging.warn('Service spec needs at lease one deployment name & port in the format NAME:PORT')
+        logging.error(
+            'Service: (' + service_spec + ') does not comply with standard. service needs to be secified in the '
+                                          'format NAME:TARGET_PORT:PORT_FORWARD_PORT(optional).')
+        exit(1)
+
+    if len(service_parts[0]) <= 0:
+        logging.warn('Service name must be string')
+        logging.error('Service: (' + service_spec + ') does not comply with standard.')
+        exit(1)
+
+    if not service_parts[1].isdigit():
+        logging.warn('Service port must be integer')
+        logging.error('Service: (' + service_spec + ') does not comply with standard. (' + service_parts[
+            1] + ') os not a valid integer.')
+        exit(1)
+
+    if len(service_parts) >= 3 and not service_parts[2].isdigit():
+        logging.warn('Service port must be integer')
+        logging.error('Service: (' + service_spec + ') does not comply with standard. (' + service_parts[
+            2] + ') os not a valid integer.')
+        exit(1)
+
+    return True
+
+
+def port_forward_service(service_spec):
+    # kubectl get pods --selector=app=authenticationservice --output=jsonpath={.items..metadata.name}
+
+    service_parts = service_spec.strip().split(':')
+
+    output = run(['kubectl', 'get', 'pods', '--selector=app={}'.format(service_parts[0].strip()),
+                  '--output=jsonpath={.items..metadata.name}'], stdout=PIPE)
+
+    if not output.stdout.decode().strip():
+        logging.error('No pods found for selector {}'.format(service_parts[0]))
+        exit(1)
+
+    local_port = service_parts[1]
+    local_proxy_port = int(local_port) + 1000
+    remote_port = local_port if (len(service_parts) == 2) else service_parts[2]
+    global nginx_directives
+    nginx_directives += """
+    server {{
+        listen {listen_port};
+        
+        server_name _;
+
+        location / {{
+                proxy_pass http://127.0.0.1:{proxy_port};
+                proxy_pass_header Server;
+                proxy_set_header Host $http_host;
+                proxy_set_header X-Real-IP $remote_addr;
+                proxy_set_header X-Scheme $scheme;
+                proxy_set_header X-Forwarded-Proto https;
+        }}
+    }}
+    """.format(listen_port=local_port, proxy_port=local_proxy_port)
+
+    Popen('kubectl port-forward {} {}:{} >> port-log.txt &'.format(
+        output.stdout.decode().strip(),
+        local_proxy_port,
+        service_parts[1] if (len(service_parts) == 2) else service_parts[2]
+    ), close_fds=True, shell=True)
+
+    print('Port Forwarding: {} to local port {} from port {}'.format(
+        service_parts[0], # Service name
+        local_port, # Local Port
+        remote_port,
+    ))
+
+def update_nginx_configs():
+    file = open('/etc/nginx/sites-enabled/default', 'w+')
+    file.truncate(0)
+    file.write(nginx_directives)
+    file.close()
+
+
+if __name__ == "__main__":
+    services = os.environ.get('SERVICES', None)
+
+    if not services:
+        print('In order to proxy services, you need to specify the SERVICES environment variable.')
+        exit(0)
+
+    service_list = services.split(',')
+
+    for service in service_list:
+        # Validate will throw error and exit if services i oncorrectly defined.
+        validate_service_spec(service)
+
+    for service in service_list:
+        port_forward_service(service)
+
+    update_nginx_configs()
+
+    Popen('service nginx restart', shell=True)