Botkit-based NL API bot (#270)

* Botkit-based NL API bot

* Fix lint issues. Refactor to best practices. Start adding tests.

* Fix typo.

* README improvements, fixes to the rc .yaml generation, minor script fixes

* Finished tests.

* fix typos, add info in parent README

cloud-language/snippets/slackbot/.gitignore

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+*.db

cloud-language/snippets/slackbot/Dockerfile

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+# Copyright 2016 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+FROM node:5.4
+
+RUN apt-get update
+RUN apt-get install -y sqlite3
+
+# Install app dependencies.
+COPY package.json /src/package.json
+WORKDIR /src
+RUN npm install
+
+# Bundle app source.
+COPY demo_bot.js /src
+
+CMD ["node", "/src/demo_bot.js"]

cloud-language/snippets/slackbot/README.md

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+
+# Building a Botkit-based Slack Bot that uses the GCP NL API and runs on Google Container Engine
+
+
+This example shows a Slack bot built using the [Botkit](https://github.com/howdyai/botkit) library.
+It runs on a Google Container Engine (Kubernetes) cluster, and uses one of the Google Cloud Platform's ML
+APIs, the Natural Language (NL) API, to interact in a Slack channel.
+
+It uses the NL API in two different ways.
+First, it uses the [Google Cloud NL API](https://cloud.google.com/natural-language/) to assess
+the [sentiment](https://cloud.google.com/natural-language/docs/basics) of any message posted to
+the channel, and if the positive or negative magnitude of the statement is
+sufficiently large, it sends a 'thumbs up' or 'thumbs down' in reaction.
+
+Additionally, it uses the NL API to identify [entities](https://cloud.google.com/natural-language/docs/basics) in each
+posted message, and tracks them in a database (using sqlite3).  Then, at any time you can query the NL slackbot to ask
+it for the top N entities used in the channel.
+
+The example uses [Google Container
+Engine](https://cloud.google.com/container-engine/), a hosted version of
+[Kubernetes](http://kubernetes.io), to run the bot, and uses [Google Container
+Registry](https://cloud.google.com/container-registry/) to store a Docker image
+for the bot.
+
+
+## Setting up your environment
+
+### Container Engine prerequisites
+
+First, set up the Google Container Engine
+[prerequisites](https://cloud.google.com/container-engine/docs/before-you-begin), including [installation of the Google Cloud SDK](https://cloud.google.com/sdk/downloads).
+
+### NL API prerequisites
+
+Next, enable the NL API for your project and authenticate to your service account as described [here](https://cloud.google.com/natural-language/docs/getting-started). (The service account step is not necessary when running the bot on Container Engine, but it is useful if you're testing locally).
+
+### Create a cluster
+
+Next,
+[create a Kubernetes cluster](https://cloud.google.com/container-engine/docs/clusters/operations#creating_a_container_cluster) using Container Engine as follows:
+
+```bash
+gcloud container clusters create "slackbot-cluster" --scopes "https://www.googleapis.com/auth/cloud-platform"
+```
+
+You can name the cluster something other than "slackbot-cluster" if you like.
+
+### Install Docker
+
+If you do not already have [Docker](https://www.docker.com/) installed locally, follow the [installation instructions](https://docs.docker.com/engine/installation/) on the Docker site.
+
+## Get a Slack token and invite the bot to a Slack channel
+
+Then, create a [Slack bot user](https://api.slack.com/bot-users) and get an
+authentication token.
+
+Then, 'invite' your new bot to a channel on a Slack team.
+
+## Running the slackbot on Kubernetes
+
+### Upload the slackbot token to Kubernetes
+
+We will be loading this token in our bot using
+[secrets](http://kubernetes.io/v1.1/docs/user-guide/secrets.html).
+
+Run the following script to create a secret .yaml file (replacing `MY-SLACK-TOKEN` with your token), then use that yaml file to create a secret on your Kubernetes cluster.
+
+```bash
+./generate-secret.sh MY-SLACK-TOKEN
+kubectl create -f slack-token-secret.yaml
+```
+
+### Build the bot's container
+
+We'll run the slackbot app in our Kubernetes cluster as a [Replication Controller](http://kubernetes.io/docs/user-guide/replication-controller/) with one replica.
+
+So, first, we need to build its Docker container. Replace `my-cloud-project-id` below with your
+Google Cloud Project ID. This tags the container so that gcloud can upload it to
+your private Google Container Registry.
+
+```bash
+export PROJECT_ID=my-cloud-project-id
+docker build -t gcr.io/${PROJECT_ID}/slack-bot .
+```
+
+Once the build completes, upload it to the Google Container registry:
+
+```bash
+gcloud docker -- push gcr.io/${PROJECT_ID}/slack-bot
+```
+
+
+### Running the container
+
+First, create a Replication Controller configuration, populated with your Google
+Cloud Project ID, so that Kubernetes knows where to find the Docker image.
+
+```bash
+./generate-rc.sh $PROJECT_ID
+```
+
+Now, tell Kubernetes to create the bot's replication controller.  This will launch 1 pod replica running the bot.
+
+```bash
+kubectl create -f slack-bot-rc.yaml
+```
+
+You can check the status of your bot with:
+
+```bash
+kubectl get pods
+```
+
+Now your bot should be online.  As a sanity check, check that it responds to a "Hello" message directed to it.
+
+Note: if you have forgotten to create the secret first, the pod won't come up successfully.
+
+## Running the bot locally
+
+If you want, you can run your slackbot locally instead.  This is handy if
+you've made some changes and want to test them out before redeploying.  To do
+this, first run:
+
+```bash
+npm install
+```
+
+Then, set GCLOUD_PROJECT to your project id:
+
+```bash
+export GCLOUD_PROJECT=my-cloud-project-id
+```
+
+Then, create a file containing your Slack token, and point 'SLACK_TOKEN_PATH' to that file when you run the script
+(substitute 'my-slack-token with your actual token):
+
+    echo my-slack-token > slack-token
+    SLACK_TOKEN_PATH=./slack-token node demo_bot.js
+
+## Using the Bot
+
+Once you've confirmed the bot is running, you can start putting it through its paces.
+
+### Sentiment Analysis
+
+The slackbot will give a 'thumbs up' or 'thumbs down' if it thinks a message is above a certain magnitude in positive or negative sentiment.
+
+E.g., try posting this message to the channel (you don't need to explicitly mention the bot in this message):
+
+```
+I hate bananas.
+```
+
+You should see that bot give a thumbs down in reply, indicatig that the NL API
+reported negative sentiment for this sentence. Next, try:
+
+```
+I love coffee.
+```
+
+This should generate a thumbs up.  Posted text won't get a reply from the bot
+unless the magnitude of the sentiment is above a given threshold, 30 by
+default.  E.g., with a neutral statement like `The temperature is seventy
+degrees.` the bot is unlikely to give a response.
+
+### Entity Analysis
+
+For every message posted to the channel, the bot-- behind the scenes-- is
+analyzing and storing information about the entities it detects.  At any time
+you can query the bot to get the current N most frequent entities, where N is
+20 by default.  It will be more interesting if you wait until a few messages
+have been posted to the channel, so that the bot has the chance to identify
+and log some entities.
+
+E.g., suppose your bot is called `nlpbot`.
+To see the top entities, send it this message:
+
+```
+@nlpbot top entities
+```
+
+
+## Shutting down
+
+To shutdown your bot, we tell Kubernetes to delete the replication controller.
+
+```bash
+kubectl delete -f slack-bot-rc.yaml
+```
+
+
+## Cleanup
+
+If you have created a container cluster, you may still get charged for the
+Google Compute Engine resources it is using, even if they are idle. To delete
+the cluster, run:
+
+```bash
+gcloud container clusters delete slackbot-cluster
+```
+
+(If you used a different name for your cluster, substitute that name for `slackbot-cluster`.)
+This deletes the Google Compute Engine instances that are running the cluster.
+