#!/bin/env python

"""
Attempts to read 'master-config.yaml' and extract remote
host information to dynamically create an inventory file
in order to run Ansible playbooks against that host.
"""

import os
import re
import shlex
import shutil
import subprocess
import sys
import yaml

try:
    HOME = os.environ['HOME']
except KeyError:
    print 'A required environment variable "$HOME" has not been set'
    exit(1)

DEFAULT_USER_CONFIG_PATH = '/etc/inventory-generator-config.yaml'
DEFAULT_MASTER_CONFIG_PATH = HOME + '/master-config.yaml'
DEFAULT_ADMIN_KUBECONFIG_PATH = HOME + '/.kube/config'

INVENTORY_FULL_PATH = HOME + '/generated_hosts'
USE_STDOUT = True

if len(sys.argv) > 1:
    INVENTORY_FULL_PATH = sys.argv[1]
    USE_STDOUT = False


class OpenShiftClientError(Exception):
    """Base exception class for OpenShift CLI wrapper"""
    pass


class InvalidHost(Exception):
    """Base exception class for host creation problems."""
    pass


class InvalidHostGroup(Exception):
    """Base exception class for host-group creation problems."""
    pass


class OpenShiftClient:
    oc = None
    kubeconfig = None

    def __init__(self, kubeconfig=DEFAULT_ADMIN_KUBECONFIG_PATH):
        """Find and store path to oc binary"""
        # https://github.com/openshift/openshift-ansible/issues/3410
        # oc can be in /usr/local/bin in some cases, but that may not
        # be in $PATH due to ansible/sudo
        paths = os.environ.get("PATH", os.defpath).split(os.pathsep) + ['/usr/local/bin', os.path.expanduser('~/bin')]

        oc_binary_name = 'oc'
        oc_binary = None

        # Use shutil.which if it is available, otherwise fallback to a naive path search
        try:
            which_result = shutil.which(oc_binary_name, path=os.pathsep.join(paths))
            if which_result is not None:
                oc_binary = which_result
        except AttributeError:
            for path in paths:
                if os.path.exists(os.path.join(path, oc_binary_name)):
                    oc_binary = os.path.join(path, oc_binary_name)
                    break

        if oc_binary is None:
            raise OpenShiftClientError('Unable to locate `oc` binary. Not present in PATH.')

        self.oc = oc_binary
        self.kubeconfig = kubeconfig

    def call(self, cmd_str):
        """Execute a remote call using `oc`"""
        cmd = [
            self.oc,
            '--config',
            self.kubeconfig
        ] + shlex.split(cmd_str)
        try:
            out = subprocess.check_output(list(cmd), stderr=subprocess.STDOUT)
        except subprocess.CalledProcessError as err:
            raise OpenShiftClientError('[rc {}] {}\n{}'.format(err.returncode, ' '.join(err.cmd), err.output))
        return out

    def whoami(self):
        """Retrieve information about the current user in the given kubeconfig"""
        return self.call('whoami')

    def get_nodes(self):
        """Retrieve remote node information as a yaml object"""
        return self.call('get nodes -o yaml')


class HostGroup:
    groupname = ""
    hosts = list()

    def __init__(self, hosts):
        if not hosts:
            return
        first = hosts[0].get_group_name()
        for h in hosts:
            if h.get_group_name() != first:
                raise InvalidHostGroup("Attempt to create HostGroup with hosts of varying groups.")

        self.hosts = hosts
        self.groupname = first

    def add_host(self, host):
        """Add a new host to this group."""
        self.hosts.append(host)

    def get_group_name(self):
        """Return the groupname associated with each aggregated host."""
        return self.groupname

    def get_hosts(self):
        """Return aggregated hosts"""
        return self.hosts

    def string(self):
        """Call the print method for each aggregated host; separated by newlines."""
        infos = ""
        for host in self.hosts:
            infos += host.string() + "\n"
        return infos


class Host:
    group = "masters"
    alias = ""
    hostname = ""
    public_hostname = ""
    ip_addr = ""
    public_ip_addr = ""

    def __init__(self, groupname):
        if not groupname:
            raise InvalidHost("Attempt to create Host with no group name provided.")
        self.group = groupname

    def get_group_name(self):
        return self.group

    def get_openshift_hostname(self):
        return self.hostname

    def host_alias(self, hostalias):
        """Set an alias for this host."""
        self.alias = hostalias

    def address(self, ip):
        """Set the ip address for this host."""
        self.ip_addr = ip

    def public_address(self, ip):
        """Set the external ip address for this host."""
        self.public_ip_addr = ip

    def host_name(self, hname):
        self.hostname = parse_hostname(hname)

    def public_host_name(self, phname):
        self.public_hostname = parse_hostname(phname)

    def string(self):
        """Print an inventory-file compatible string with host information"""
        info = ""
        if self.alias:
            info += self.alias + " "
        elif self.hostname:
            info += self.hostname + " "
        elif self.ip_addr:
            info += self.ip_addr + " "
        if self.ip_addr:
            info += "openshift_ip=" + self.ip_addr + " "
        if self.public_ip_addr:
            info += "openshift_public_ip=" + self.public_ip_addr + " "
        if self.hostname:
            info += "openshift_kubelet_name_override=" + self.hostname + " "
        if self.public_hostname:
            info += "openshift_public_hostname=" + self.public_hostname

        return info


def parse_hostname(host):
    """Remove protocol and port from given hostname.
    Return parsed string"""
    no_proto = re.split('^http(s)?\:\/\/', host)
    if no_proto:
        host = no_proto[-1]

    no_port = re.split('\:[0-9]+(/)?$', host)
    if no_port:
        host = no_port[0]

    return host


def main():
    """Parse master-config file and populate inventory file."""
    # set default values
    USER_CONFIG = os.environ.get('CONFIG')
    if not USER_CONFIG:
        USER_CONFIG = DEFAULT_USER_CONFIG_PATH

    # read user configuration
    try:
        config_file_obj = open(USER_CONFIG, 'r')
        raw_config_file = config_file_obj.read()
        user_config = yaml.load(raw_config_file)
        if not user_config:
            user_config = dict()
    except IOError as err:
        print "Unable to find or read user configuration file '{}': {}".format(USER_CONFIG, err)
        exit(1)

    master_config_path = user_config.get('master_config_path', DEFAULT_MASTER_CONFIG_PATH)
    if not master_config_path:
        master_config_path = DEFAULT_MASTER_CONFIG_PATH

    admin_kubeconfig_path = user_config.get('admin_kubeconfig_path', DEFAULT_ADMIN_KUBECONFIG_PATH)
    if not admin_kubeconfig_path:
        admin_kubeconfig_path = DEFAULT_ADMIN_KUBECONFIG_PATH

    try:
        file_obj = open(master_config_path, 'r')
    except IOError as err:
        print "Unable to find or read host master configuration file '{}': {}".format(master_config_path, err)
        exit(1)

    raw_text = file_obj.read()

    y = yaml.load(raw_text)
    if y.get("kind", "") != "MasterConfig":
        print "Bind-mounted host master configuration file is not of 'kind' MasterConfig. Aborting..."
        exit(1)

    # finish reading config file and begin gathering
    # cluster information for inventory file
    file_obj.close()

    # set inventory values based on user configuration
    ansible_ssh_user = user_config.get('ansible_ssh_user', 'root')
    ansible_become_user = user_config.get('ansible_become_user')

    openshift_uninstall_images = user_config.get('openshift_uninstall_images', False)
    openshift_install_examples = user_config.get('openshift_install_examples', True)
    openshift_deployment_type = user_config.get('openshift_deployment_type', 'origin')

    openshift_release = user_config.get('openshift_release')
    openshift_image_tag = user_config.get('openshift_image_tag')
    openshift_logging_image_version = user_config.get('openshift_logging_image_version')
    openshift_disable_check = user_config.get('openshift_disable_check')

    # extract host config info from parsed yaml file
    asset_config = y.get("assetConfig")
    master_config = y.get("kubernetesMasterConfig")
    etcd_config = y.get("etcdClientInfo")

    # if master_config is missing, error out; we expect to be running on a master to be able to
    # gather enough information to generate the rest of the inventory file.
    if not master_config:
        msg = "'kubernetesMasterConfig' missing from '{}'; unable to gather all necessary host information..."
        print msg.format(master_config_path)
        exit(1)

    master_public_url = y.get("masterPublicURL")
    if not master_public_url:
        msg = "'kubernetesMasterConfig.masterPublicURL' missing from '{}'; Unable to connect to master host..."
        print msg.format(master_config_path)
        exit(1)

    oc = OpenShiftClient(admin_kubeconfig_path)

    # ensure kubeconfig is logged in with provided user, or fail with a friendly message otherwise
    try:
        oc.whoami()
    except OpenShiftClientError as err:
        msg = ("Unable to obtain user information using the provided kubeconfig file. "
               "Current context does not appear to be able to authenticate to the server. "
               "Error returned from server:\n\n{}")
        print msg.format(str(err))
        exit(1)

    # connect to remote host using the provided config and extract all possible node information
    nodes_config = yaml.load(oc.get_nodes())

    # contains host types (e.g. masters, nodes, etcd)
    host_groups = dict()
    openshift_logging_install_logging = False
    is_etcd_deployed = master_config.get("storage-backend", "") in ["etcd3", "etcd2", "etcd"]

    if asset_config and asset_config.get('loggingPublicURL'):
        openshift_logging_install_logging = True

    openshift_logging_install_logging = user_config.get("openshift_logging_install_logging", openshift_logging_install_logging)

    m = Host("masters")
    m.address(master_config["masterIP"])
    m.public_host_name(master_public_url)
    host_groups["masters"] = HostGroup([m])

    if nodes_config:
        node_hosts = list()
        for node in nodes_config.get("items", []):
            if node["kind"] != "Node":
                continue

            n = Host("nodes")

            address = ""
            internal_hostname = ""
            for item in node["status"].get("addresses", []):
                if not address and item['type'] in ['InternalIP', 'LegacyHostIP']:
                    address = item['address']

                if item['type'] == 'Hostname':
                    internal_hostname = item['address']

            n.address(address)
            n.host_name(internal_hostname)
            node_hosts.append(n)

        host_groups["nodes"] = HostGroup(node_hosts)

    if etcd_config:
        etcd_hosts = list()
        for url in etcd_config.get("urls", []):
            e = Host("etcd")
            e.host_name(url)
            etcd_hosts.append(e)

        host_groups["etcd"] = HostGroup(etcd_hosts)

    # open new inventory file for writing
    if USE_STDOUT:
        inv_file_obj = sys.stdout
    else:
        try:
            inv_file_obj = open(INVENTORY_FULL_PATH, 'w+')
        except IOError as err:
            print "Unable to create or open generated inventory file: {}".format(err)
            exit(1)

    inv_file_obj.write("[OSEv3:children]\n")
    for group in host_groups:
        inv_file_obj.write("{}\n".format(group))
    inv_file_obj.write("\n")

    inv_file_obj.write("[OSEv3:vars]\n")
    if ansible_ssh_user:
        inv_file_obj.write("ansible_ssh_user={}\n".format(ansible_ssh_user))
    if ansible_become_user:
        inv_file_obj.write("ansible_become_user={}\n".format(ansible_become_user))
        inv_file_obj.write("ansible_become=yes\n")

    if openshift_uninstall_images:
        inv_file_obj.write("openshift_uninstall_images={}\n".format(str(openshift_uninstall_images)))
    if openshift_deployment_type:
        inv_file_obj.write("openshift_deployment_type={}\n".format(openshift_deployment_type))
    if openshift_install_examples:
        inv_file_obj.write("openshift_install_examples={}\n".format(str(openshift_install_examples)))

    if openshift_release:
        inv_file_obj.write("openshift_release={}\n".format(str(openshift_release)))
    if openshift_image_tag:
        inv_file_obj.write("openshift_image_tag={}\n".format(str(openshift_image_tag)))
    if openshift_logging_image_version:
        inv_file_obj.write("openshift_logging_image_version={}\n".format(str(openshift_logging_image_version)))
    if openshift_disable_check:
        inv_file_obj.write("openshift_disable_check={}\n".format(str(openshift_disable_check)))
    inv_file_obj.write("\n")

    inv_file_obj.write("openshift_logging_install_logging={}\n".format(str(openshift_logging_install_logging)))
    inv_file_obj.write("\n")

    for group in host_groups:
        inv_file_obj.write("[{}]\n".format(host_groups[group].get_group_name()))
        inv_file_obj.write(host_groups[group].string())
        inv_file_obj.write("\n")

    inv_file_obj.close()


if __name__ == '__main__':
    main()
