Two engines: glue and jinjar (#21)

* glue and jinjar both work

* update README

R/source_sql_to_dataframe.R

@@ -5,7 +5,8 @@ source_sql_to_dataframe <- function(path, params = NULL) {
   rlang::eval_bare(rlang::parse_expr(connection_call))
   on.exit(DBI::dbDisconnect(con))
   query <- readr::read_file(path)
-  if (!is.null(params)) {
+  template_engine <- sqltargets_option_get("sqltargets.template_engine")
+  if (template_engine == "jinjar") {
     query <- jinjar::render(
       query,
       params = params,
@@ -18,6 +19,14 @@ source_sql_to_dataframe <- function(path, params = NULL) {
         comment_close = sqltargets_option_get("sqltargets.jinja_comment_close"),
       )
     )
+  } else {
+    query <- glue::glue_sql(
+      query,
+      .con = con,
+      .open = sqltargets_option_get("sqltargets.glue_sql_opening_delimiter"),
+      .close = sqltargets_option_get("sqltargets.glue_sql_closing_delimiter"),
+      .envir = params
+      )
   }
   out <- DBI::dbGetQuery(con, query)
   msg <- glue::glue("{basename(path)} executed:\n Rows: {nrow(out)}\n Columns: {ncol(out)}")

R/sqltargets-option.R

@@ -7,13 +7,24 @@
 #'
 #' @details
 #'
-#' ## Available Options
+#' Available Options
+#'
+#'  - `"sqltargets.template_engine"` - Either 'glue' or 'jinjar'. Determines how the query file should be parsed`.
+#'
+#'  - `"sqltargets.glue_sql_opening_delimiter"` - character. Length 1. The opening delimiter passed to `glue::glue_sql()`.
+#'
+#'  - `"sqltargets.glue_sql_closing_delimiter"` - character. Length 1. The closing delimiter passed to `glue::glue_sql()`.
 #'
 #'  - `"sqltargets.jinja_block_open"` - character. Length 1. The opening delimiter passed to `jinjar::jinjar_config()`.
+#'
 #'  - `"sqltargets.jinja_block_close"` - character. Length 1. The closing delimiter passed to `jinjar::jinjar_config()`.
+#'
 #'  - `"sqltargets.jinja_variable_open"` - character. Length 1. The closing delimiter passed to `jinjar::jinjar_config()`.
+#'
 #'  - `"sqltargets.jinja_variable_close"` - character. Length 1. The closing delimiter passed to `jinjar::jinjar_config()`.
+#'
 #'  - `"sqltargets.jinja_comment_open"` - character. Length 1. The closing delimiter passed to `jinjar::jinjar_config()`.
+#'
 #'  - `"sqltargets.jinja_comment_close"` - character. Length 1. The closing delimiter passed to `jinjar::jinjar_config()`.
 #' @rdname sqltargets-options
 #' @export

R/zzz.R

@@ -6,6 +6,9 @@ sqltargets_env <- function() {
 
 .onAttach <- function(lib, pkg) {
   jinjar_defaults <- jinjar::default_config()
+  sqltargets.env$sqltargets.template_engine <- "glue"
+  sqltargets.env$sqltargets.glue_sql_opening_delimiter <- "{"
+  sqltargets.env$sqltargets.glue_sql_closing_delimiter <- "}"
   sqltargets.env$sqltargets.jinja_block_open <- jinjar_defaults$block_open
   sqltargets.env$sqltargets.jinja_block_close <- jinjar_defaults$block_close
   sqltargets.env$sqltargets.jinja_comment_open <- jinjar_defaults$comment_open

README.Rmd

@@ -40,36 +40,13 @@ You can install the development version of sqltargets with:
 remotes::install_github("daranzolin/sqltargets)
 ```
 
-## Example
-
-```{r example}
-library(targets)
-library(sqltargets)
-
-tar_dir({  # 
-# Unparameterized SQL query:
-  lines <- c(
-    "-- !preview conn=DBI::dbConnect(RSQLite::SQLite())",
-    "select 1 AS my_col",
-    ""
-  )
-  writeLines(lines, "query.sql")
-# Include the query in a pipeline as follows.
-  tar_script({
-    library(sqltargets)
-    list(
-      tar_sql(query, path = "query.sql")
-      )
-    }, ask = FALSE)
-  })
-```
-
-## Specifying dependencies
+## Dependencies
 
 Use `tar_load` or `targets::tar_load` within a SQL comment to indicate query 
 dependencies. Check the dependencies of any query with `tar_sql_deps`.
 
 ```{r}
+library(sqltargets)
 lines <- c(
    "-- !preview conn=DBI::dbConnect(RSQLite::SQLite())",
    "-- targets::tar_load(data1)",
@@ -82,36 +59,70 @@ lines <- c(
  tar_sql_deps(query)
 ```
 
-## Passing parameters
+## Parameters
 
-Pass parameters (presumably from another object in your targets project) from a named list with 
-'glue' syntax: `{param}`.
+You can pass parameters (presumably from another object in your targets project) to `tar_sql()` using one of two 'template engines': [glue](https://github.com/tidyverse/glue) or 'Jinja' (courtesy of [the 'jinjar' package.)](https://github.com/davidchall/jinjar)  
+
+Set the 'template engine' with `sqltargets_option_set("sqltargets.template_engine", "jinjar")`. ('glue' is the default.)
+
+With glue:
 
 `query.sql`
 
 ```sql
 -- !preview conn=DBI::dbConnect(RSQLite::SQLite())
--- tar_load(query_params)
+-- tar_load(params)
 select id
 from table
 where age > {age_threshold}
 ```
 
+`_targets.R`
+
 ```{r eval = FALSE}
-tar_script({
-  library(targets)
-  library(sqltargets)
-  list(
-    tar_target(query_params, list(age_threshold = 30)),
-    tar_sql(report, path = "query.sql", query_params = query_params)
-    )
-  }, ask = FALSE)
-
-tar_visnetwork()
+library(targets)
+library(sqltargets)
+list(
+  tar_target(params, list(age_threshold = 30)),
+  tar_sql(report, path = "query.sql", params = params)
+  )
 ```
 
 ![](inst/tar_visnetwork.png)
 
+With 'Jinja':
+
+`query.sql`
+
+```sql
+-- !preview conn=DBI::dbConnect(RSQLite::SQLite())
+-- tar_load(payment_methods)
+select
+order_id,
+{% for payment_method in params.payment_methods %}
+sum(case when payment_method = '{{payment_method}}' then amount end) as {{payment_method}}_amount
+{% if not loop.is_last %},{% endif %}
+{% endfor %}
+from payments
+group by 1
+```
+
+`_targets.R`
+
+```{r eval = FALSE}
+library(targets)
+library(sqltargets)
+
+sqltargets_option_set("sqltargets.template_engine", "jinjar")
+
+list(
+  tar_target(payment_methods, list(payment_methods = c("bank_transfer", "credit_card", "gift_card"))),
+  tar_sql(report, path = "query.sql", params = payment_methods)
+  )
+```
+
+Note that `loop.is_last` differs from typical Jinja (`loop.last`). Refer to [this 'jinjar' vignette](https://davidchall.github.io/jinjar/articles/template-syntax.html) for other syntactical differences.
+
 ## Code of Conduct
 
 Please note that the sqltargets project is released with a [Contributor Code of Conduct](https://contributor-covenant.org/version/2/1/CODE_OF_CONDUCT.html). By contributing to this project, you agree to abide by its terms.

README.md

@@ -40,38 +40,14 @@ You can install the development version of sqltargets with:
 remotes::install_github("daranzolin/sqltargets)
 ```
 
-## Example
-
-``` r
-library(targets)
-#> Warning: package 'targets' was built under R version 4.2.2
-library(sqltargets)
-
-tar_dir({  # 
-# Unparameterized SQL query:
-  lines <- c(
-    "-- !preview conn=DBI::dbConnect(RSQLite::SQLite())",
-    "select 1 AS my_col",
-    ""
-  )
-  writeLines(lines, "query.sql")
-# Include the query in a pipeline as follows.
-  tar_script({
-    library(sqltargets)
-    list(
-      tar_sql(query, path = "query.sql")
-      )
-    }, ask = FALSE)
-  })
-```
-
-## Specifying dependencies
+## Dependencies
 
 Use `tar_load` or `targets::tar_load` within a SQL comment to indicate
 query dependencies. Check the dependencies of any query with
 `tar_sql_deps`.
 
 ``` r
+library(sqltargets)
 lines <- c(
    "-- !preview conn=DBI::dbConnect(RSQLite::SQLite())",
    "-- targets::tar_load(data1)",
@@ -85,36 +61,78 @@ lines <- c(
 #> [1] "data1" "data2"
 ```
 
-## Passing parameters
+## Parameters
+
+You can pass parameters (presumably from another object in your targets
+project) to `tar_sql()` using one of two ‘template engines’:
+[glue](https://github.com/tidyverse/glue) or ‘Jinja’ (courtesy of [the
+‘jinjar’ package.)](https://github.com/davidchall/jinjar)
 
-Pass parameters (presumably from another object in your targets project)
-from a named list with ‘glue’ syntax: `{param}`.
+Set the ‘template engine’ with
+`sqltargets_option_set("sqltargets.template_engine", "jinjar")`. (‘glue’
+is the default.)
+
+With glue:
 
 `query.sql`
 
 ``` sql
 -- !preview conn=DBI::dbConnect(RSQLite::SQLite())
--- tar_load(query_params)
+-- tar_load(params)
 select id
 from table
 where age > {age_threshold}
 ```
 
+`_targets.R`
+
 ``` r
-tar_script({
-  library(targets)
-  library(sqltargets)
-  list(
-    tar_target(query_params, list(age_threshold = 30)),
-    tar_sql(report, path = "query.sql", query_params = query_params)
-    )
-  }, ask = FALSE)
-
-tar_visnetwork()
+library(targets)
+library(sqltargets)
+list(
+  tar_target(params, list(age_threshold = 30)),
+  tar_sql(report, path = "query.sql", params = params)
+  )
 ```
 
 ![](inst/tar_visnetwork.png)
 
+With ‘Jinja’:
+
+`query.sql`
+
+``` sql
+-- !preview conn=DBI::dbConnect(RSQLite::SQLite())
+-- tar_load(payment_methods)
+select
+order_id,
+{% for payment_method in params.payment_methods %}
+sum(case when payment_method = '{{payment_method}}' then amount end) as {{payment_method}}_amount
+{% if not loop.is_last %},{% endif %}
+{% endfor %}
+from payments
+group by 1
+```
+
+`_targets.R`
+
+``` r
+library(targets)
+library(sqltargets)
+
+sqltargets_option_set("sqltargets.template_engine", "jinjar")
+
+list(
+  tar_target(payment_methods, list(payment_methods = c("bank_transfer", "credit_card", "gift_card"))),
+  tar_sql(report, path = "query.sql", params = payment_methods)
+  )
+```
+
+Note that `loop.is_last` differs from typical Jinja (`loop.last`). Refer
+to [this ‘jinjar’
+vignette](https://davidchall.github.io/jinjar/articles/template-syntax.html)
+for other syntactical differences.
+
 ## Code of Conduct
 
 Please note that the sqltargets project is released with a [Contributor

tests/testthat/test-tar-sql.R

@@ -35,7 +35,32 @@ targets::tar_test("tar_sql() works", {
   expect_equal(sort(targets::tar_progress()$name), sort(c("data", "report", "query.sql")))
 })
 
-targets::tar_test("tar_sql() for Jinja queries 1", {
+targets::tar_test("tar_sql() with glue engine", {
+  lines <- c(
+    "-- !preview conn=DBI::dbConnect(RSQLite::SQLite())",
+    "-- tar_load(query_params)",
+    "select {val} as {col_name}",
+    ""
+  )
+  writeLines(lines, "query.sql")
+  targets::tar_script({
+    library(sqltargets)
+    sqltargets_option_set("sqltargets.template_engine", "glue")
+    list(
+      targets::tar_target(params, list(val = 3, col_name = "column1")),
+      tar_sql(
+        report,
+        path = "query.sql",
+        params = params
+      )
+    )
+  })
+  suppressMessages(targets::tar_make(callr_function = NULL))
+  out <- targets::tar_read(report)
+  expect_equal(out, data.frame(column1 = 3))
+})
+
+targets::tar_test("tar_sql() with jinjar engine", {
   lines <- c(
     "-- !preview conn=DBI::dbConnect(RSQLite::SQLite())",
     "-- tar_load(params)",
@@ -45,6 +70,7 @@ targets::tar_test("tar_sql() for Jinja queries 1", {
   writeLines(lines, "query.sql")
   targets::tar_script({
     library(sqltargets)
+    sqltargets_option_set("sqltargets.template_engine", "jinjar")
     list(
       targets::tar_target(params, list(val = 3, col_name = "column1")),
       tar_sql(
@@ -73,6 +99,7 @@ targets::tar_test("tar_sql() for Jinja for loop", {
   writeLines(lines, "query.sql")
   targets::tar_script({
     library(sqltargets)
+    sqltargets_option_set("sqltargets.template_engine", "jinjar")
     list(
       targets::tar_target(params, list(payment_methods = c("bank_transfer", "credit_card", "gift_card"))),
       tar_sql(