479 mirai lockfile@main

[gogonzo]

#1276

@pawelru @m7pr
This is a mirai alternative. Package seems to address the biggest issues reported during a research:

• mirai has a native support of ExtendedTask
• mirai is not being killed when runApp is executed (like callr does)
• mirai by default opens a deamon in parallel R session without a need to handle the future::plan.
• mirai has only one dependency in the whole dependency tree.

Disadvantages so far:

• we need to pass and set options, system vars, working directory and .libPaths mirai don't start with custom .libPaths nor options  shikokuchuo/mirai#122

How does it work:

• lockfile creation is invoked in init before application starts. This prevents to start the process each time when a new shiny session starts. Process is invoked as a promise and eventually teal_app.lock will be created
• When shiny session starts download lockfile button is hidden by default. If promise is eventually resolved and lockfile is created then download button is shown.
• alternatively, app developer can pre-compute lockfile and provide its path in teal.renv.lockfile option. In such case renv::snapshot will be skipped and user lockfile will be used in an app.

Logs and notifications

Logs are printed for app developer while notifications are presented to the app user:

1. When app uses precomputed file:

• log in init: Lockfile set using option "teal.renv.lockfile" - skipping automatic creation.
• no notification to the app user.

2. When app automatically determines snapshot:

• log in init: Lockfile creation started based on { getwd() }.
• log If lockfile created: Lockfile {path} containing { n-pkgs } packages created{ with errors or warnings }.
• notification if lockfile created: Lockfile available to download
• log if lockfile not created: Lockfile creation failed.
• notification if lockfile not created: Lockfile creation failed.

[gogonzo]

@pawelru this is ready ⭐

[gogonzo]

minor comments

[m7pr]

@pawelru since @gogonzo is the author, he can not approve the PR. I implemented all the changes we discussed and I am stating this is solid. Any final words?

[pawelru]

Looks good 👍 it took us a while to get there :)

[m7pr]

@gogonzo you can do the honors of merging this in : ) great colab team!