DiagrammeR (https://github.com/rich-iannone/DiagrammeR)— Trigger a script from inside a graph series and modify that graph series. Uses the 'create_series' and 'trigger_script' functions.

DiagrammeR_trigger_script.R

# Install the latest version of DiagrammeR from GitHub
devtools::install_github("rich-iannone/DiagrammeR")

# Ensure that the package is loaded
library("DiagrammeR")

# So, here's a script that essentially takes an empty graph series, and
# creates a new graph on each new day it is triggered. It will create
# random nodes each time it's triggered and add those nodes to the graph
# belonging to the current day. Throughout the script, '_SELF_' refers
# to the graph series in which the script is contained.
# And, the script is actually a character object
sample_node_script <-
'
# Provide default graph attributes
graph_attrs <- c("layout = twopi",
                 "overlap = FALSE",
                 "outputorder = edgesfirst")

# Provide default node attributes
node_attrs <- c("shape = circle",
                "fixedsize = TRUE",
                "width = 1",
                "penwidth = 1",
                "color = DodgerBlue",
                "style = filled",
                "fillcolor = Aqua",
                "alpha_fillcolor = 0.5",
                "fontname = Helvetica",
                "fontcolor = Grey25")

# Provide default edge attributes
edge_attrs <- c("arrowhead = dot",
                "minlen = 1.5",
                "color = Green",
                "penwidth = 2")

# If there is no graph available in the series, then, make one!
if (graph_count(graph_series = _SELF_) == 0){

  _SELF_ <-
    add_to_series(graph = create_graph(graph_attrs = graph_attrs,
                                       node_attrs = node_attrs,
                                       edge_attrs = edge_attrs,
                                       graph_name = paste0("data_", Sys.Date()),
                                       graph_time = as.character(Sys.Date()),
                                       graph_tz = Sys.timezone()),
                  graph_series = _SELF_)

}

# Determine the index of the last graph in the series
last_graph_in_series <- graph_count(graph_series = _SELF_)

# If it is a new day, create a new graph in the series to populate with data
if (Sys.Date() > as.Date(_SELF_$graphs[[last_graph_in_series]]$graph_time,
                          tz = _SELF_$graphs[[last_graph_in_series]]$graph_tz)){

  _SELF_ <-
    add_to_series(graph = create_graph(graph_attrs = graph_attrs,
                                       node_attrs = node_attrs,
                                       edge_attrs = edge_attrs,
                                       graph_name = paste0("data_", Sys.Date()),
                                       graph_time = as.character(Sys.Date()),
                                       graph_tz = Sys.timezone()),
                  graph_series = _SELF_)

  last_graph_in_series <- graph_count(graph_series = _SELF_)
}

# Create a node to place into the graph
letters <- paste(sample(LETTERS, 5), collapse = "")

# Add node to the most recent graph and attach it to
# another randomly picked node available in the graph.
# Note that adding an edge only works in the case that
# there is at least one node available in the graph.
# For convenience, the relevant graph is extracted from
# the series, then placed back in the series.
if (!is.na(sample(get_nodes(_SELF_$graphs[[last_graph_in_series]]), 1))){

  graph <- _SELF_$graphs[[last_graph_in_series]]

  graph <- add_node(graph = graph,
                    node = letters)

  graph <- add_edges(graph = graph,
                     from = letters,
                     to = sample(get_nodes(graph = graph), 1))

} else {

  graph <- _SELF_$graphs[[last_graph_in_series]]

  graph <- add_node(graph = graph,
                    node = letters)
}

# Remove old graph from series
_SELF_ <- remove_from_series(graph_series = _SELF_,
                             index = "last")

# Add new graph to correct position in series
# The "add_to_series" function always adds a graph to the
# end of the graph series.
_SELF_ <- add_to_series(graph = graph,
                        graph_series = _SELF_)

return(_SELF_)
'

# Create an empty graph series of the 'temporal' type and add
# that script as one of the graph series' 'series scripts'
series_temporal <- create_series(series_type = "temporal",
                                 series_scripts = sample_node_script)

# Call the function 60 times, this will generate 60 random nodes
# with 59 edges 
for (i in seq(1, 60)){

  series_temporal <- trigger_script(graph_series = series_temporal,
                                    script = 1)
  if (i == 60) break
}

# Display the results in the RStudio Viewer
render_graph_from_series(graph_series = series_temporal,
                         graph_no = graph_count(series_temporal))

# Get some basic information about the graphs in the graph series object
series_info(series_temporal)