---
title: "Version, share, and deploy a model with vetiver"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{vetiver}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

```{r}
#| include: false
knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>",
  eval = requireNamespace("parsnip", quietly = TRUE) && requireNamespace("recipes", quietly = TRUE) && requireNamespace("workflows", quietly = TRUE)
)
```

The goal of vetiver is to provide fluent tooling for MLOps tasks for your trained model including:

- versioning
- storing
- sharing
- deploying

For more extensive documentation, visit <https://vetiver.posit.co/>.

## Create a `vetiver_model()`

The vetiver package is extensible, with generics that can support many kinds of models. For this example, let's consider one kind of model supported by vetiver, a [tidymodels](https://www.tidymodels.org/) workflow that encompasses both feature engineering and model estimation.

```{r}
library(parsnip)
library(recipes)
library(workflows)
data(bivariate, package = "modeldata")
bivariate_train

biv_rec <-
  recipe(Class ~ ., data = bivariate_train) |>
  step_BoxCox(all_predictors())|>
  step_normalize(all_predictors())

svm_spec <-
  svm_linear(mode = "classification") |>
  set_engine("LiblineaR")

svm_fit <- 
  workflow(biv_rec, svm_spec) |>
  fit(sample_frac(bivariate_train, 0.7))
```

This `svm_fit` object is a fitted workflow, with both feature engineering and model parameters estimated using the training data `bivariate_train`. We can create a `vetiver_model()` from this trained model; a `vetiver_model()` collects the information needed to store, version, and deploy a trained model.

```{r}
library(vetiver)
v <- vetiver_model(svm_fit, "biv_svm")
v
```

Think of this `vetiver_model()` as a deployable model object.

## Store and version your model

You can store and version your model by choosing a [pins](https://pins.rstudio.com) "board" for it, including a local folder, Posit Connect, Amazon S3, and more. Most pins boards have versioning turned on by default, but we can turn it on explicitly for our temporary demo board. When we write the `vetiver_model()` to our board, the binary model object is stored on our board together with necessary metadata, like the packages needed to make a prediction and the model's input data prototype for checking new data at prediction time.

```{r}
#| message: false
library(pins)
model_board <- board_temp(versioned = TRUE)
model_board |> vetiver_pin_write(v)
```

Let's train our model again with a new version of the dataset and write it once more to our board.

```{r}
#| message: false
svm_fit <- 
  workflow(biv_rec, svm_spec) |>
  fit(sample_frac(bivariate_train, 0.7))

v <- vetiver_model(svm_fit, "biv_svm")

model_board |> vetiver_pin_write(v)
```

Both versions are stored, and we have access to both.

```{r}
model_board |> pin_versions("biv_svm")
```

The primary purpose of pins is to make it easy to share data artifacts, so depending on the board you choose, your pinned `vetiver_model()` can be shareable with your collaborators.

## Deploy your model

You can deploy your model by creating a [Plumber](https://www.rplumber.io/) router, and adding a POST endpoint for making predictions.

```{r}
library(plumber)
pr() |>
  vetiver_api(v)
```

To start a server using this object, pipe (`|>`) to `pr_run(port = 8088)` or your port of choice. This allows you to interact with your vetiver API locally and debug it. Plumber APIs such as these can be [hosted in a variety of ways](https://www.rplumber.io/articles/hosting.html). You can use the function `vetiver_write_plumber()` to create a ready-to-go `plumber.R` file that is especially suited for [Posit Connect](https://posit.co/products/enterprise/connect/).

```{r}
#| eval: false
vetiver_write_plumber(model_board, "biv_svm")
```


```{r}
#| echo: false
#| comment: ''
tmp <- tempfile()
vetiver_write_plumber(model_board, "biv_svm", file = tmp)
cat(readr::read_lines(tmp), sep = "\n")
```

In a real-world situation, you would see something like `b <- board_connect()` or `b <- board_s3()` here instead of our temporary demo board. Notice that the deployment is strongly linked to a *specific version* of the pinned model; if you pin another version of the model after you deploy your model, your deployed model will not be affected.

## Predict from your model endpoint

A model deployed via vetiver can be treated as a special `vetiver_endpoint()` object.

```{r}
library(vetiver)
endpoint <- vetiver_endpoint("http://127.0.0.1:8088/predict")
endpoint
```

If such a deployed model endpoint is running via one R process (either remotely on a server or locally, perhaps via a [background job in the RStudio IDE](https://docs.posit.co/ide/user/ide/guide/tools/jobs.html)), you can make predictions with that deployed model and new data in another, separate R process. 

``` r
data(bivariate, package = "modeldata")
predict(endpoint, bivariate_test)
#> # A tibble: 710 × 1
#>    .pred_class
#>    <chr>      
#>  1 One        
#>  2 Two        
#>  3 One        
#>  4 Two        
#>  5 Two        
#>  6 One        
#>  7 Two        
#>  8 Two        
#>  9 Two        
#> 10 One        
#> # … with 700 more rows
```

Being able to `predict()` on a vetiver model endpoint takes advantage of the model's input data prototype and other metadata that is stored with the model.


