From 442d4e8ae02b71abb237ece2fce6dc6cb93a9d0d Mon Sep 17 00:00:00 2001
From: Orion Kindel <cakekindel@gmail.com>
Date: Sun, 11 Jun 2023 16:43:53 -0500
Subject: [PATCH] feat: run migrations against running database

---
 .env.schema             |  3 +++
 docker-compose.yml      |  4 ++--
 schema/000_revision.sql |  8 ++++++++
 scripts/build.sh        | 14 ++++++--------
 scripts/diff.sh         |  4 ++--
 scripts/env.sh          |  4 +++-
 scripts/migrate.sh      | 38 ++++++++++++++++++++++++++++++++++++++
 7 files changed, 62 insertions(+), 13 deletions(-)
 create mode 100644 .env.schema
 create mode 100644 schema/000_revision.sql
 mode change 100644 => 100755 scripts/migrate.sh

diff --git a/.env.schema b/.env.schema
new file mode 100644
index 0000000..e520b19
--- /dev/null
+++ b/.env.schema
@@ -0,0 +1,3 @@
+POSTGRES_USER=postgres
+POSTGRES_PASSWORD=password
+POSTGRES_DB=dnim
diff --git a/docker-compose.yml b/docker-compose.yml
index 578b231..a85ff3a 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -9,7 +9,7 @@ services:
     volumes:
       - "./data/base:/var/lib/postgres/data"
     env_file:
-      - "./.env"
+      - "./.env.schema"
   head:
     container_name: "head"
     image: "postgres:15.3-bullseye"
@@ -19,4 +19,4 @@ services:
     volumes:
       - "./data/head:/var/lib/postgres/data"
     env_file:
-      - "./.env"
+      - "./.env.schema"
diff --git a/schema/000_revision.sql b/schema/000_revision.sql
new file mode 100644
index 0000000..3ea3f72
--- /dev/null
+++ b/schema/000_revision.sql
@@ -0,0 +1,8 @@
+create table public.migration
+  ( from_revision text not null
+  , to_revision   text not null
+  , performed_on  timestamp not null default now()
+  , script        text not null
+  );
+
+insert into migration (from_revision, to_revision, script) values ('empty', 'empty', '');
diff --git a/scripts/build.sh b/scripts/build.sh
index 4f13a01..6bfc533 100755
--- a/scripts/build.sh
+++ b/scripts/build.sh
@@ -1,6 +1,6 @@
 #! /usr/bin/bash
 
-source ./scripts/env.sh
+source ./scripts/env.sh ./.env.schema
 
 rev=${1:-HEAD}
 
@@ -25,17 +25,15 @@ switch_back_to_head() {
 }
 trap 'switch_back_to_head' EXIT
 
-url=postgresql://$POSTGRES_USER:$POSTGRES_PASSWORD@localhost:$port/$POSTGRES_DB
+url=postgresql://$POSTGRES_USER:$POSTGRES_PASSWORD@localhost:$port
 
-psql \
-  --quiet \
-  $url \
-  --command="drop schema public cascade; create schema public;" \
-  1>/dev/null
+dropdb=$(mktemp)
+echo "drop database dnim with (force); create database dnim;" > "$dropdb"
+psql --quiet "$url/postgres" --file="$dropdb" 1>/dev/null
 
 ls ./schema/ | xargs -I{} \
    psql \
    --quiet \
-   $url \
+   "$url/$POSTGRES_DB" \
    --file=./schema/{} \
    1>/dev/null
diff --git a/scripts/diff.sh b/scripts/diff.sh
index d179cbc..bf9474e 100755
--- a/scripts/diff.sh
+++ b/scripts/diff.sh
@@ -2,7 +2,7 @@
 
 set -e
 
-source ./scripts/env.sh
+source ./scripts/env.sh ./.env.schema
 
 rev=${1:-}
 
@@ -20,4 +20,4 @@ docker compose up -d
 ./scripts/build.sh HEAD
 
 echo "migrate from $rev => HEAD" 1>&2
-migra --unsafe $base_url $head_url
+migra --unsafe $base_url $head_url || echo "migra exited with code $?. this is /probably/ fine" 1>&2
diff --git a/scripts/env.sh b/scripts/env.sh
index fde2126..3212962 100755
--- a/scripts/env.sh
+++ b/scripts/env.sh
@@ -1,3 +1,5 @@
 #! /usr/bin/bash
 
-while read line; do export $line; done < ./.env
+file=${1:-./.env}
+
+while read line; do export "$line"; done < "$file"
diff --git a/scripts/migrate.sh b/scripts/migrate.sh
old mode 100644
new mode 100755
index 3686f0f..7bc84ae
--- a/scripts/migrate.sh
+++ b/scripts/migrate.sh
@@ -1,3 +1,41 @@
 #! /usr/bin/bash
 
+set -e
 
+source ./scripts/env.sh ./.env
+
+if [[ -n $(git status --porcelain) ]]; then
+  echo "git working tree dirty" 1>&2;
+  exit 1;
+fi
+
+head=$(git show --format=format:%h -q)
+
+get_dnim_database_count="copy (select count(*) from pg_database where datname = 'dnim') to stdout with null as '';"
+dnim_database_count=$(psql "$POSTGRES_ROOT_CONNECTION_URL" -c "$get_dnim_database_count")
+
+if [[ "$dnim_database_count" = "0" ]]; then
+  echo "fresh database"
+  psql "$POSTGRES_ROOT_CONNECTION_URL" -c "create database dnim;"
+  ls ./schema/ | xargs -I{} psql --quiet "$POSTGRES_CONNECTION_URL" --file=./schema/{} 1>/dev/null
+  last_revision='empty'
+  script=''
+else
+  get_last_revision="copy (select to_revision from migration order by performed_on desc limit 1) to stdout with null as '';"
+  last_revision=$(psql "$POSTGRES_CONNECTION_URL" -c "$get_last_revision")
+  script=$(./scripts/diff.sh "$last_revision")
+
+  if [[ "$1" = "--greenlight" ]]; then
+    psql "$POSTGRES_CONNECTION_URL" -c "$script"
+  else
+    to_review="tmp/migrate_${last_revision}_to_${head}.sql"
+    echo "$script" > "$to_review"
+    echo "script written to $to_review"
+    echo "review and rerun with --greenlight to apply migration"
+    exit
+  fi
+fi
+
+insert_migration="insert into migration (from_revision, to_revision, script) values ('$last_revision', '$head', \$migration\$$script\$migration\$);"
+psql "$POSTGRES_CONNECTION_URL" -c "$insert_migration"
+echo "inserted migration"