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Read a Microsoft Fabric/OneLake Delta table (ADLS Gen2)

Source: R/fabric_onelake_read_delta_table.R
fabric_onelake_read_delta_table.Rd

Authenticates to OneLake (ADLS Gen2), resolves the table's _delta_log to determine the current active Parquet parts, downloads only those parts to a local staging directory, and returns the result as a tibble.

Usage

fabric_onelake_read_delta_table(
  table_path,
  workspace_name,
  lakehouse_name,
  tenant_id = Sys.getenv("FABRICQUERYR_TENANT_ID"),
  client_id = Sys.getenv("FABRICQUERYR_CLIENT_ID", unset =
    "04b07795-8ddb-461a-bbee-02f9e1bf7b46"),
  dest_dir = NULL,
  verbose = TRUE,
  dfs_base = "https://onelake.dfs.fabric.microsoft.com"
)

Arguments

table_path

Character. Table name or nested path (e.g. "Patienten" or "Patienten/patienten_hash"). Only the last path segment is used as the table directory under Tables/.

workspace_name

Character. Fabric workspace display name or GUID (this is the ADLS filesystem/container name).

lakehouse_name

Character. Lakehouse item name, with or without the .Lakehouse suffix (e.g. "Lakehouse" or "Lakehouse.Lakehouse").

tenant_id

Character. Entra ID (Azure AD) tenant GUID. Defaults to Sys.getenv("FABRICQUERYR_TENANT_ID") if missing.

client_id

Character. App registration (client) ID. Defaults to Sys.getenv("FABRICQUERYR_CLIENT_ID"), falling back to the Azure CLI app id "04b07795-8ddb-461a-bbee-02f9e1bf7b46" if not set.

dest_dir

Character or NULL. Local staging directory for Parquet parts. If NULL (default), a temp dir is used and cleaned up on exit.

verbose

Logical. Print progress messages via {cli}. Default TRUE.

dfs_base

Character. OneLake DFS endpoint. Default "https://onelake.dfs.fabric.microsoft.com".

Value

A tibble with the table's current rows (0 rows if the table is empty).

Details

  • In Microsoft Fabric, OneLake exposes each workspace as an ADLS Gen2 filesystem. Within a Lakehouse item, Delta tables are stored under Tables/<table> with a _delta_log/ directory that tracks commit state. This helper replays the JSON commits to avoid double-counting compacted/removed files.

  • Ensure the account/principal you authenticate with has access via Lakehouse -> Manage OneLake data access (or is a member of the workspace).

  • AzureAuth is used to acquire the token. Be wary of caching behavior; you may want to call AzureAuth::clean_token_directory() to clear cached tokens if you run into issues

Examples

# Example is not executed since it requires configured credentials for Fabric
if (FALSE) { # \dontrun{
df <- fabric_onelake_read_delta_table(
  table_path     = "Patients/PatientInfo",
  workspace_name = "PatientsWorkspace",
  lakehouse_name = "Lakehouse.Lakehouse",
  tenant_id      = Sys.getenv("FABRICQUERYR_TENANT_ID"),
  client_id      = Sys.getenv("FABRICQUERYR_CLIENT_ID")
)
dplyr::glimpse(df)
} # }