src/tosca/parser.py

from toscaparser.tosca_template import ToscaTemplate, ValidationError
from default import TOSCA_RECIPES_DIR
from grpc_client.resources import RESOURCES
from grpc_client.models_accessor import GRPCModelsAccessor

class TOSCA_Parser:

    def compute_dependencies(self, template, models_by_name):
        """
        NOTE this method is augmenting self.template, isn't there a more explicit way to achieve it?
        """
        for nodetemplate in template.nodetemplates:
            nodetemplate.dependencies = []
            nodetemplate.dependencies_names = []
            for reqs in nodetemplate.requirements:
                for (k,v) in reqs.items():
                    name = v["node"]
                    if (name in models_by_name):
                        nodetemplate.dependencies.append(models_by_name[name])
                        nodetemplate.dependencies_names.append(name)

                    # go another level deep, as our requirements can have requirements...
                    # NOTE do we still need to go deep?
                    for sd_req in v.get("requirements",[]):
                        for (sd_req_k, sd_req_v) in sd_req.items():
                            name = sd_req_v["node"]
                            if (name in models_by_name):
                                nodetemplate.dependencies.append(models_by_name[name])
                                nodetemplate.dependencies_names.append(name)

    @staticmethod
    def topsort_dependencies(g):

        # Get set of all nodes, including those without outgoing edges
        keys = set(g.keys())
        values = set({})
        for v in g.values():
            values = values | set(v.dependencies_names)

        all_nodes = list(keys | values)
        steps = all_nodes


        # Final order
        order = []

        # DFS stack, not using recursion
        stack = []

        # Unmarked set
        unmarked = all_nodes

        # visiting = [] - skip, don't expect 1000s of nodes, |E|/|V| is small

        while unmarked:
            stack.insert(0, unmarked[0])  # push first unmarked

            while (stack):
                n = stack[0]
                add = True
                try:
                    for m in g[n].dependencies_names:
                        if (m in unmarked):
                            add = False
                            stack.insert(0, m)
                except KeyError:
                    pass
                if (add):
                    if (n in steps and n not in order):
                        order.append(n)
                    item = stack.pop(0)
                    try:
                        unmarked.remove(item)
                    except ValueError:
                        pass

        noorder = list(set(steps) - set(order))
        return order + noorder

    @staticmethod
    def populate_model(model, data):
        for k,v in data.iteritems():
            setattr(model, k, v)
        return model

    @staticmethod
    def _translate_exception(msg):
        readable = []
        for line in msg.splitlines():
            if line.strip().startswith('MissingRequiredFieldError'):
                readable.append(line)
            if line.strip().startswith('UnknownFieldError'):
                readable.append(line)

        if len(readable) > 0:
            return '/n'.join(readable)
        else:
            return msg

    def save_recipe_to_tmp_file(self, recipe):
        tmp_file = open(self.recipe_file, 'w')
        tmp_file.write(recipe)
        tmp_file.close()

    @staticmethod
    def get_tosca_models_by_name(template):
        models_by_name = {}
        for node in template.nodetemplates:
            models_by_name[node.name] = node
        return models_by_name

    @staticmethod
    def get_ordered_models_template(ordered_models_name, templates_by_model_name):
        ordered_models_templates = []
        for name in ordered_models_name:
            if name in templates_by_model_name:
                ordered_models_templates.append(templates_by_model_name[name])
        return ordered_models_templates

    @staticmethod
    def populate_dependencies(model, requirements, saved_models):
        for dep in requirements:
            class_name = dep.keys()[0]
            related_model = saved_models[dep[class_name]['node']]
            setattr(model, "%s_id" % class_name, related_model.id)
        return model

    def __init__(self, recipe):

        # the template returned by TOSCA-Parser
        self.template = None
        # dictionary containing the models in the recipe and their template
        self.templates_by_model_name = None
        # list of models ordered by requirements
        self.ordered_models_name = []
        # dictionary containing the saved model
        self.saved_model_by_name = {}

        self.ordered_models_template = []
        self.recipe_file = TOSCA_RECIPES_DIR + '/tmp.yaml'

        self.recipe = recipe

    def execute(self):
        try:
            # [] save the recipe to a tmp file
            self.save_recipe_to_tmp_file(self.recipe)
            # [] parse the recipe with TOSCA Parse
            self.template = ToscaTemplate(self.recipe_file)
            # [] get all models in the recipe
            self.templates_by_model_name = self.get_tosca_models_by_name(self.template)
            # [] compute requirements
            self.compute_dependencies(self.template, self.templates_by_model_name)
            # [] topsort requirements
            self.ordered_models_name = self.topsort_dependencies(self.templates_by_model_name)
            # [] topsort templates
            self.ordered_models_template = self.get_ordered_models_template(self.ordered_models_name, self.templates_by_model_name)

            for recipe in self.ordered_models_template:
                # get properties from tosca
                data = recipe.templates[recipe.name]['properties']
                # [] get model by class name
                class_name = recipe.type.replace("tosca.nodes.", "")
                if class_name not in RESOURCES:
                    raise Exception("Nodetemplate %s's type %s is not a known resource" % (recipe.name, class_name))
                model = GRPCModelsAccessor.get_model_from_classname(class_name, data)
                # [] populate model with data
                model = self.populate_model(model, data)
                # [] check if the model has requirements
                # [] if it has populate them
                model = self.populate_dependencies(model, recipe.requirements, self.saved_model_by_name)
                # [] save or update
                model.save()

                self.saved_model_by_name[recipe.name] = model

        except ValidationError as e:
            if e.message:
                exception_msg = TOSCA_Parser._translate_exception(e.message)
            else:
                exception_msg = TOSCA_Parser._translate_exception(str(e))
            raise Exception(exception_msg)