####################################################################
# Importing a cloned Nixpkgs repo (from my home directory), because
# the latest channels don't have Elixir 1.9.
# See https://nixos.org/nix/manual/#idm140737317975776 for the meaning
# of `<nixpkgs>` and `~` in Nix expressions (towards the end of that
# section).
####################################################################
# The Nixpkgs commit used for pinning below is quite old,
#
# Oct 1, 2021, 8:37 PM EDT
# https://github.com/NixOS/nixpkgs/tree/751ce748bd1ebac94442dfeaa8bc3f100d73a9f6
#
# but they can be overridden using `nix-shell`'s `--argstr`
# (never figured out how to use `--arg`):
#
# nix-shell \
# -v \
# -E 'import (builtins.fetchurl "https://raw.githubusercontent.com/toraritte/shell.nixes/main/elixir-phoenix-postgres/shell.nix")' \
# --argstr "nixpkgs_commit" "3ad7b8a7e8c2da367d661df6c3742168c53913fa"
#
# (And all that on one line:
# nix-shell -v -E 'import (builtins.fetchurl "https://raw.githubusercontent.com/toraritte/shell.nixes/main/_composables/postgres_shell.nix")' --argstr "nixpkgs_commit" "3ad7b8a7e8c2da367d661df6c3742168c53913fa"
# )
#
# The rules to compose "raw" GitHub links from the regular view page seems straightforward:
#
# https://github.com/ toraritte/shell.nixes/blob/main/elixir-phoenix-postgres/shell.nix
# https://raw.githubusercontent.com/toraritte/shell.nixes/ main/elixir-phoenix-postgres/shell.nix
{ nixpkgs_commit ? "751ce748bd1ebac94442dfeaa8bc3f100d73a9f6" }:
let
pkgs =
import
# The downloaded archive will be (temporarily?) housed in the Nix store
# e.g., "/nix/store/gk9x7syd0ic6hjrf0fs6y4bsd16zgscg-source"
# (Try any of the `fetchTarball` commands below in `nix repl`, and it
# will print out the path.)
( builtins.fetchTarball "https://github.com/nixos/nixpkgs/tarball/${nixpkgs_commit}" )
{ config = {}; overlays = []; }
;
in
pkgs.mkShell {
buildInputs = with pkgs; [
# beam.packages.erlangR22.elixir_1_9
elixir
# postgresql_11
postgresql
nodejs-12_x
git
# TODO this will won't install on mac
inotify-tools
];
shellHook = ''
######################################################################
# Create a diretory for the generated artifacts #
######################################################################
mkdir .nix-shell
export NIX_SHELL_DIR=$PWD/.nix-shell
######################################################################
# Put the PostgreSQL databases in the project diretory. #
######################################################################
export PGDATA=$NIX_SHELL_DIR/db
####################################################################
# Put any Mix-related data in the project directory
####################################################################
export MIX_HOME="$NIX_SHELL_DIR/.mix"
export MIX_ARCHIVES="$MIX_HOME/archives"
######################################################################
# Clean up after exiting the Nix shell using `trap`. #
# ------------------------------------------------------------------ #
# Idea taken from #
# https://unix.stackexchange.com/questions/464106/killing-background-processes-started-in-nix-shell
# and the answer provides a way more sophisticated solution. #
# #
# The main syntax is `trap ARG SIGNAL` where ARG are the commands to #
# be executed when SIGNAL crops up. See `trap --help` for more. #
######################################################################
trap \
"
########################################################
# Stop PostgreSQL #
########################################################
pg_ctl -D $PGDATA stop
########################################################
# Delete `.nix-shell` directory #
# ---------------------------------- #
# The first step is going back to the project root, #
# otherwise `.nix-shell` won't get deleted. At least #
# it didn't for me when exiting in a subdirectory. #
########################################################
cd $PWD
rm -rf $NIX_SHELL_DIR
" \
EXIT
######################################################################
# If database is not initialized (i.e., $PGDATA directory does not #
# exist), then set it up. Seems superfulous given the cleanup step #
# above, but handy when one had to force reboot the iron. #
######################################################################
if ! test -d $PGDATA
then
########################################################
# Init PostgreSQL #
# #
# NOTE `initdb` vs `createdb` #
# https://stackoverflow.com/questions/50210158/whats-the-difference-between-initdb-usr-local-var-db-and-createdb-db
# https://www.postgresql.org/docs/current/app-initdb.html
########################################################
pg_ctl initdb -D $PGDATA
########################################################
# PORT ALREADY IN USE #
########################################################
# If another `nix-shell` is running with a PostgreSQL #
# instance, the logs will show complaints that the #
# default port 5432 is already in use. Edit the line #
# below with a different port number, uncomment it, #
# and try again. #
########################################################
# sed -i "s|^#port.*$|port = 5433|" $PGDATA/postgresql.conf
fi
########################################################################
# Configure and start PostgreSQL #
# ==================================================================== #
# Setting all necessary configuration options via `pg_ctl` (which #
# is basically a wrapper around `postgres`) instead of editing #
# `postgresql.conf` directly with `sed`. See docs: #
# #
# + https://www.postgresql.org/docs/current/app-pg-ctl.html #
# + https://www.postgresql.org/docs/current/app-postgres.html #
# #
# See more on the caveats at #
# https://discourse.nixos.org/t/how-to-configure-postgresql-declaratively-nixos-and-non-nixos/4063/1
# but recapping out of paranoia: #
# #
# > use `SHOW` commands to check the options because `postgres -C` #
# > "_returns values from postgresql.conf_" (which is not changed by #
# > supplying the configuration options on the command line) and #
# > "_it does not reflect parameters supplied when the cluster was #
# > started._" #
# #
# OPTION SUMMARY #
# -------------------------------------------------------------------- #
# #
# + `unix_socket_directories` #
# #
# PostgreSQL will attempt to create a pidfile in #
# `/run/postgresql` by default, but it will fail as it #
# doesn't exist. By changing the configuration option #
# below, it will get created in $PGDATA. #
# #
# + `listen_addresses` #
# #
# In tandem with edits in `pg_hba.conf` (see #
# `HOST_COMMON` below), it configures PostgreSQL to #
# allow remote connections (otherwise only `localhost` #
# will get authorized and the rest of the traffic #
# will be discarded). #
# #
# NOTE: the edit to `pga_hba.conf` needs to come #
# **before** `pg_ctl start` (or the service #
# needs to be restarted otherwise), because then #
# the changes are not being reloaded. #
# #
# More info on setting up and troubleshooting remote #
# PosgreSQL connections (these are all mirrors of the #
# same text; again, paranoia): #
# #
# + https://stackoverflow.com/questions/24504680/connect-to-postgres-server-on-google-compute-engine
# + https://stackoverflow.com/questions/47794979/connecting-to-postgres-server-on-google-compute-engine
# + https://medium.com/scientific-breakthrough-of-the-afternoon/configure-postgresql-to-allow-remote-connections-af5a1a392a38
# + https://gist.github.com/toraritte/f8c7fe001365c50294adfe8509080201#file-configure-postgres-to-allow-remote-connection-md
#
# + `log*` #
# #
# Setting up basic logging, to see remote connections #
# for example. #
# #
# See the docs for more: #
# https://www.postgresql.org/docs/current/runtime-config-logging.html
########################################################################
# !!!!!!!!!!!! These are only suitable for development.
# ! INSECURE ! (Not sure if running a production server
# !!!!!!!!!!!! from `nix-shell` is a good idea anyway:)
HOST_COMMON="host\s\+all\s\+all"
sed -i "s|^$HOST_COMMON.*127.*$|host all all 0.0.0.0/0 trust|" $PGDATA/pg_hba.conf
sed -i "s|^$HOST_COMMON.*::1.*$|host all all ::/0 trust|" $PGDATA/pg_hba.conf
pg_ctl \
-D $PGDATA \
-l $PGDATA/postgres.log \
-o "-c unix_socket_directories='$PGDATA'" \
-o "-c listen_addresses='*'" \
-o "-c log_destination='stderr'" \
-o "-c logging_collector=on" \
-o "-c log_directory='log'" \
-o "-c log_filename='postgresql-%Y-%m-%d_%H%M%S.log'" \
-o "-c log_min_messages=info" \
-o "-c log_min_error_statement=info" \
-o "-c log_connections=on" \
start
####################################################################
# Install Node.js dependencies if not done yet.
####################################################################
if test -d "$PWD/assets/" && ! test -d "$PWD/assets/node_modules/"
then
(cd assets && npm install)
fi
####################################################################
# If $MIX_HOME doesn't exist, set it up.
####################################################################
if ! test -d $MIX_HOME
then
######################################################
# ... but first, test whether there is a `_backup`
# directory. Had issues with installing Hex on NixOS,
# and Hex and Phoenix can be copied from there, just
# in case.
######################################################
if test -d "$PWD/_backup"
then
cp -r _backup/.mix .nix-shell/
else
######################################################
# Install Hex and Phoenix via the network
######################################################
yes | mix local.hex
yes | mix archive.install hex phx_new
fi
fi
if test -f "mix.exs"
then
# These are not in the `if` section above, because of
# the `hex` install glitch, it could be that there is
# already a `$MIX_HOME` folder. See 2019-08-05_0553
mix deps.get
######################################################
# `ecto.setup` is defined in `mix.exs` by default when
# Phoenix project is generated via `mix phx.new`.
# It does `ecto.create`, `ecto.migrate`, and run
# `priv/seeds`.
######################################################
mix ecto.setup
fi
'';
####################################################################
# Without this, almost everything fails with locale issues when
# using `nix-shell --pure` (at least on NixOS).
# See
# + https://github.com/NixOS/nix/issues/318#issuecomment-52986702
# + http://lists.linuxfromscratch.org/pipermail/lfs-support/2004-June/023900.html
####################################################################
LOCALE_ARCHIVE = if pkgs.stdenv.isLinux then "${pkgs.glibcLocales}/lib/locale/locale-archive" else "";
}
# vim: set tabstop=2 shiftwidth=2 expandtab: