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googlePubsubR

This library offers an easy to use interface for the Google Pub/Sub REST API (docs here).

Not an official Google product.

Setup

You can install the package from CRAN or get the dev version from Github:

install.packages("googlePubsubR")

# Or get the dev version from Github
devtools::install_github("andodet/googlePubsubR@dev")

In order to use the library, you will need:

• An active GCP project
• The Pub/Sub API correctly activated
• JSON credentials for a service account or another method of authentication (e.g token). You can pass the path of the file as an argument to pubsub_auth or setting an GCP_AUTH_FILE env variable.
• A GCP_PROJECT env variable set with a valid GCP project id. Since 0.0.3, GCP project id can also be set using ps_project_set.

Usage

On a very basic level, the library can be used to publish messages, pull and acknowledge them.
The following example shows how to:

1. Create topics and subscriptions
2. Encode a dataframe as a Pub/Sub message
3. Publish a message
4. Pull and decode messages from a Pub/Sub subscription
5. Delete resources

library(googlePubsubR)
library(base64enc)
library(jsonlite)

# Authenticate 
pubsub_auth()

# Create resources
topic_readme <- topics_create("readme-topic")
sub_readme <- subscriptions_create("readme-sub", topic_readme)

# Prepare the message
msg <- mtcars %>%
  toJSON(auto_unbox = TRUE) %>%
  # Pub/Sub expects a base64 encoded string
  msg_encode() %>% 
  PubsubMessage() 

# Publish the message!
topics_publish(msg, topic_readme)

# Pull the message from server
msgs_pull <- subscriptions_pull(sub_readme)

msg_decoded <- msgs_pull$receivedMessages$message$data %>%
  msg_decode() %>% 
  fromJSON()

head(msg_decoded)

# Prints
# mpg cyl disp  hp drat    wt  qsec vs am gear carb
# Mazda RX4         21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
# Mazda RX4 Wag     21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
# Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
# Hornet 4 Drive    21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
# Hornet Sportabout 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2
# Valiant           18.1   6  225 105 2.76 3.460 20.22  1  0    3    1

# We can acknowledge that the message has been consumed
subscriptions_ack(msgs_pull$receivedMessages$ackId, sub_readme)
# [1] TRUE

# A subsequent pull will return no messages from the server
subscriptions_pull(sub_readme)
# named list()

# Cleanup resources
topics_delete(topic_readme)
subscriptions_delete(sub_readme)

Use cases

The main use-cases for Pub/Sub messaging queue:

• Stream data into Dataflow pipelines
• Trigger workflows hosted in Cloud Run or Cloud Functions
• Expand interactivity in Shiny dashboards (more on this here).
• Add event driven actions in {plumbr}

Contributing

In order to contribute to googlePubsubR you’ll need to go through the following steps:

1. Set up a GCP project and create a service account with Pub/Sub admin rights.

2. Download a JSON key for the newly created account. Naming the file .gcp_creds.json and placing it in the package root folder will make it automatically gitignored.

3. Set up the following env vars (either through a tool like direnv or a .Renviron file).

   GCP_AUTH_FILE=<paht_to_json_auth_file>
   GCP_PROJECT=<gcp_project_id_string>

4. Check everything is set up correctly by running a test run via devtools::test().

These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.
Health stats visible at Monitor.