Merge branch 'environments' into 'master'

Add environments

See merge request !1

.gitignore

@@ -40,3 +40,6 @@ public
 
 # Package bibliography
 packages.bib
+
+# GitLab review app
+review-app.html

.gitlab-ci.yml

-image: rocker/verse:3.4.1
+image: rocker/verse:4.0.2
 
-pages:
+.bookdown:
   stage: deploy
   script:
-  - Rscript -e "bookdown::render_book('index.Rmd', 'all', output_dir = 'public')"
+    - Rscript -e "bookdown::render_book('index.Rmd', 'all', output_dir = 'public')"
   artifacts:
     paths:
-    - public
+      - public
+
+pages:
+  extends: .bookdown
+  only:
+    - master
+
+mr-review:
+  extends: .bookdown
+  after_script:
+    - echo "ENVIRONMENT_URL=https://$CI_PROJECT_NAMESPACE.$CI_PAGES_DOMAIN/-/$CI_PROJECT_NAME/-/jobs/$CI_JOB_ID/artifacts/public/index.html" >> deploy.env
+  artifacts:
+    reports:
+      dotenv: deploy.env
+  environment:
+    name: review/$CI_COMMIT_REF_NAME
+    url: $ENVIRONMENT_URL
   only:
-  - master
+    - merge_requests

01-details.Rmd

@@ -7,10 +7,10 @@ A comprehensive documentation of `GitLab Pages` can be found here: https://docs.
 `GitLab CI` configuration file is a `YAML` file.  
 The configuration file begins with `image` declaration. It indicates to the `GitLab Runner` which [`Docker`](https://www.docker.com/) image it has to pull for executing the `CI` job.
 
-```{r comment=NA, class.output='yaml', echo=FALSE}
+```{r find-image-name, comment=NA, class.output='yaml', echo=FALSE}
 image <- 
   readLines("./.gitlab-ci.yml") %>%
-  stringr::str_subset("image") %T>%
+  stringr::str_subset("rocker") %T>%
   cat() %>%
   yaml::yaml.load() %$%
   image %>%
@@ -24,7 +24,7 @@ Using a `Rocker` image, **you ensure the reproducibility of your `bookdown` webs
 
 In order to build a `GitLab Pages` website, you have to declare a `pages` job. That is the remaining lines of the `.gitlab-ci.yml` file:
 
-```{r comment=NA, class.output='yaml', echo=FALSE}
+```{r extract-pages-job, comment=NA, class.output='yaml', echo=FALSE}
 readChar("./.gitlab-ci.yml", 1e5) %>%
   strsplit("(?=\\npages:)", perl = TRUE) %>%
   unlist() %>%

index.Rmd

 ---
-title: "Easily publish an R bookdown website with GitLab Pages"
+title: "Get the full power of GitLab CI for your bookdown project"
 author: "Romain Lesur"
 description: "This book provides a demo of a bookdown website published on GitLab Pages"
 date: "`r Sys.Date()`"
@@ -12,6 +12,7 @@ favicon: "favicon.ico"
 output:
   bookdown::gitbook: 
     includes:
+      in_header: review-app.html
       after_body: disqus.html
     config:
       toc:
@@ -25,7 +26,7 @@ output:
     citation_package: natbib
 ---
 
-# Overview: a simple workflow {-}
+# Overview: a powerful workflow {-}
 ```{r setup, include=FALSE}
 library(magrittr)
 ```
@@ -34,19 +35,47 @@ library(magrittr)
 knitr::write_bib(c(.packages(), 'bookdown'), 'packages.bib')
 ```
 
-Publishing an `R` [@R-base] `bookdown` [@R-bookdown] website with [`GitLab Pages`](https://about.gitlab.com/features/pages/) is as easy as:
+```{r gitlab-review-app, echo=FALSE}
+# this chunk builds an HTML fragment which contains a script tag
+# this script adds a review app for merge requests
+html_content <- ""
 
-- hosting a repository on [`GitLab`](https://gitlab.com)
+# the CI_MERGE_REQUEST_IID environment variable only exists when a job runs
+# with only: [merge_requests]
+if (nzchar(Sys.getenv("CI_MERGE_REQUEST_IID"))) {
+  fmt <- "<script defer data-project-id='%s' data-project-path='%s' data-merge-request-id='%s' data-mr-url='%s' id='review-app-toolbar-script' src='%s/assets/webpack/visual_review_toolbar.js'></script>"
+  vars <- Sys.getenv(c(
+    'CI_PROJECT_ID', 
+    'CI_PROJECT_PATH', 
+    'CI_MERGE_REQUEST_IID', 
+    'CI_SERVER_URL', 
+    'CI_SERVER_URL'
+  ))
+  html_content <- do.call(sprintf, c(list(fmt = fmt), vars))
+}
+
+cat(html_content, file = "review-app.html")
+```
+
+Publishing a **bookdown** [@R-bookdown] website with [GitLab Pages](https://about.gitlab.com/features/pages/) is as easy as:
+
+- hosting a repository on [GitLab](https://gitlab.com)
 - adding a configuration file to the project
 
-## Host a project on <code>GitLab</code> {-}
+You will get a hosting service for your **bookdown** book (like GitHub Pages) and great features
+which are not available with GitHub Actions:
 
-As [`GitHub`](https://www.github.com), [`GitLab`](https://gitlab.com) is a web-based [`Git`](https://git-scm.com/) repository manager. Creating a new project on [`GitLab`](https://gitlab.com) is fairly intuitive for [`GitHub`](https://www.github.com) users. [`GitLab`](https://gitlab.com) users can create unlimitate private projects for free (see [here](https://about.gitlab.com/gitlab-com/)). 
+- **pull requests previews**
+- **a review application dedicated to non git users that allows them to comment on these previews**
 
-[`GitLab`](https://gitlab.com) also offers a continuous integration service ([`GitLab CI`](https://about.gitlab.com/features/gitlab-ci-cd/)) and a static websites hosting service ([`GitLab Pages`](https://about.gitlab.com/features/pages/)) in its free plan ^[CI pipelines are limited to 2,000 minutes per month].  
-These features are also present in the open source software [`GitLab Community Edition (CE)`](https://about.gitlab.com/products/).
+## Host a project on GitLab {-}
 
-## Add a `GitLab CI` configuration file {-}
+As [GitHub](https://www.github.com), [GitLab](https://gitlab.com) is a web-based [Git](https://git-scm.com/) repository manager. Creating a new project on [GitLab](https://gitlab.com) is fairly intuitive for [GitHub](https://www.github.com) users. [GitLab](https://gitlab.com) users can create unlimitate private projects for free (see [here](https://about.gitlab.com/gitlab-com/)). 
+
+[GitLab](https://gitlab.com) also offers a continuous integration service ([GitLab CI](https://about.gitlab.com/features/gitlab-ci-cd/)) and a static websites hosting service ([GitLab Pages](https://about.gitlab.com/features/pages/)) in its free plan ^[CI pipelines are limited to 2,000 minutes per month].  
+These features are also present in the open source software [GitLab Community Edition (CE)](https://about.gitlab.com/products/) which is widely used in industry as a self hosted git repository manager.
+
+## Add a GitLab CI configuration file {-}
 
 Add the following `.gitlab-ci.yml` file in the root of the project:
 ```{r insert-ci-file, comment=NA, class.output='yaml', echo=FALSE}
@@ -57,8 +86,7 @@ For explanations, see section \@ref(CI-file-details).
 
 ## See the result {-}
 
-When the `CI` job is done, the website is served on `GitLab Pages`.  
+When the CI job is done, the website is served on GitLab Pages.  
 CI jobs status can be found in `CI / CD menu > Jobs`. An example, [here](https://gitlab.com/RLesur/bookdown-gitlab-pages/-/jobs).  
 The address of the `GitLab Pages` project can be found in `Settings > Pages`. An example, [here](https://gitlab.com/RLesur/bookdown-gitlab-pages/pages).
 
-