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| library(shiny) | |
| library(bslib) | |
| library(minhub) | |
| library(magrittr) | |
| source("model-session.R") | |
| repo <- "EleutherAI/pythia-70m" | |
| repo <- Sys.getenv("MODEL_REPO", unset = repo) | |
| sess <- model_session$new() | |
| max_n_tokens <- 100 | |
| system_prompt = "<|SYSTEM|># StableLM Tuned (Alpha version) | |
| - StableLM is a helpful and harmless open-source AI language model developed by StabilityAI. | |
| - StableLM is excited to be able to help the user, but will refuse to do anything that could be considered harmful to the user. | |
| - StableLM is more than just an information source, StableLM is also able to write poetry, short stories, and make jokes. | |
| - StableLM will refuse to participate in anything that could harm a human. | |
| " | |
| ui <- page_fillable( | |
| theme = bs_theme(bootswatch = "minty"), | |
| shinyjs::useShinyjs(), | |
| card( | |
| height="90%", | |
| heights_equal = "row", | |
| width = 1, | |
| fillable = FALSE, | |
| card_body(id = "messages", gap = 5, fillable = FALSE) | |
| ), | |
| layout_column_wrap( | |
| width = 1/2, | |
| textInput("prompt", label = NULL, width="100%"), | |
| actionButton("send", "Send", width = "100%") | |
| ) | |
| ) | |
| server <- function(input, output, session) { | |
| prompt <- reactiveVal(value = system_prompt) | |
| n_tokens <- reactiveVal(value = 0) | |
| msg_id <- reactiveVal(value = 0) | |
| observeEvent(input$send, { | |
| if (is.null(input$prompt) || input$prompt == "") { | |
| return() | |
| } | |
| shinyjs::disable("send") | |
| updateActionButton(inputId = "send", label = "Waiting for model...") | |
| insert_message(msg_id, as.character(glue::glue("🤗: {input$prompt}"))) | |
| # we modify the prompt to trigger the 'next_token' reactive | |
| prompt(paste0(prompt(), "<|USER|>", input$prompt, "<|ASSISTANT|>")) | |
| }) | |
| next_token <- eventReactive(prompt(), ignoreInit = TRUE, { | |
| prompt() %>% | |
| sess$generate() %>% | |
| promises::then( | |
| onFulfilled = function(x) {x}, | |
| onRejected = function(x) { | |
| insert_message(msg_id, paste0("😭 Error generating token.", as.character(x))) | |
| updateActionButton(inputId = "send", label = "Failing generation. Contact admin.") | |
| NULL | |
| } | |
| ) | |
| }) | |
| observeEvent(next_token(), { | |
| tok <- next_token() | |
| n_tokens(n_tokens() + 1) | |
| tok %>% promises::then(function(tok) { | |
| if (n_tokens() == 1) { | |
| insert_message(msg_id, paste0("🤖: ", tok), append = FALSE) | |
| } else { | |
| insert_message(msg_id, tok, append = TRUE) | |
| } | |
| if (tok != "" && n_tokens() < max_n_tokens) { | |
| prompt(paste0(prompt(), tok)) | |
| } else { | |
| shinyjs::enable("send") | |
| updateActionButton(inputId = "send", label = "Send") | |
| n_tokens(0) | |
| } | |
| }) | |
| }) | |
| # Observer used at app startup time to allow using the 'Send' button once the | |
| # model has been loaded. | |
| model_loaded <- reactiveVal() | |
| event_reload <- reactiveVal(val = 0) | |
| observeEvent(event_reload(), ignoreNULL=FALSE, { | |
| # the model is already loaded, we just make sure the send button is enabled | |
| if (!is.null(sess$is_loaded) && sess$is_loaded) { | |
| shinyjs::enable("send") | |
| updateActionButton(inputId = "send", label = "Send") | |
| return() | |
| } | |
| # the model isn't loaded, this we disable the send button and | |
| # show that we are loading the model | |
| shinyjs::disable("send") | |
| updateActionButton(inputId = "send", label = "Loading the model...") | |
| # the model isn't loaded and no task is trying to load it, so we start a new | |
| # task to load it | |
| if (is.null(sess$is_loaded)) { | |
| cat("Started loading model ....", "\n") | |
| model_loaded(sess$load_model(repo)) | |
| sess$is_loaded <- FALSE # not yet loaded, but loading | |
| } else { | |
| # the model is loading, but this is handled by another session. We should | |
| # come back to this observer later to enable the send button once model | |
| # is loaded. | |
| invalidateLater(5000, session) | |
| return() | |
| } | |
| # this runs for the cases where sess$is_loaded was NULL | |
| # ie there was no model currently loading. | |
| m <- model_loaded() %>% | |
| promises::then(onFulfilled = function(x) { | |
| cat("Model has been loaded!", "\n") | |
| shinyjs::enable("send") | |
| updateActionButton(inputId = "send", label = "Send") | |
| sess$is_loaded <- TRUE | |
| TRUE | |
| }, onRejected = function(x) { | |
| shinyjs::disable("send") | |
| insert_message(msg_id, paste0("😭 Error loading the model:\n", as.character(x))) | |
| sess$is_loaded <- NULL # means failure! | |
| sess$sess <- NULL | |
| if (event_reload() < 10) { | |
| Sys.sleep(5) | |
| event_reload(event_reload() + 1) | |
| } | |
| FALSE | |
| }) | |
| model_loaded(m) | |
| }) | |
| } | |
| insert_message <- function(message_id, msg, append = FALSE) { | |
| if (!append) { | |
| id <- message_id() + 1 | |
| message_id(id) | |
| insertUI( | |
| "#messages", | |
| "beforeEnd", | |
| immediate = TRUE, | |
| ui = card(style="margin-bottom:5px;", card_body( | |
| p(id = paste0("msg-",id), msg) | |
| )) | |
| ) | |
| } else { | |
| id <- message_id() | |
| shinyjs::runjs(glue::glue( | |
| "document.getElementById('msg-{id}').textContent += '{msg}'" | |
| )) | |
| } | |
| # scroll to bottom | |
| shinyjs::runjs("var elem = document.getElementById('messages'); elem.scrollTop = elem.scrollHeight;") | |
| id | |
| } | |
| shinyApp(ui, server) | |