Add environment variable support to backend

README.md

@@ -8,4 +8,20 @@ The blog has the following functionality
 - Editing Posts
 - Deleting Posts
 
-Additionally, it tracks the category that posts are in, allowing filtering posts by category.
+Additionally, it tracks the category that posts are in, allowing filtering posts by category.
+
+Xnoeblog is intended to be used with Docker, an example compose file is provided within this repository. The backend container can be configured using the following environment variables
+
+- DB_HOST: Hostname of the database
+- DB_USER: Database user
+- DB_PASS: Database user password
+- DB_NAME: Name of database to use
+- XNOEBLOG_USER: Default user 
+- XNOEBLOG_PASS: Default password
+
+All of these values are optional. Xnoeblog backend defaults to creating no user and using the following values for database if no environment variables are provided
+
+- DB_HOST=db
+- DB_USER=root
+- DB_PASS=password
+- DB_NAME=xnoeblog

backend/app/Main.hs

@@ -12,6 +12,7 @@ import Data.ByteString.Lazy.Char8 as L (pack)
 import Data.ByteString as B (unpack, ByteString)
 import Text.Printf
 import System.Random (newStdGen, randomRs)
+import System.ReadEnvVar (lookupEnv)
 
 import Crypto.Hash.SHA256 as SHA256
 
@@ -317,7 +318,34 @@ handleWhoami c = do
 
 main :: IO ()
 main = do
-  c <- connectPostgreSQL "host=database user=blog password=root dbname=blog"
+  dbhostvar <- lookupEnv "DB_HOST"
+  dbuservar <- lookupEnv "DB_USER"
+  dbpassvar <- lookupEnv "DB_PASS"
+  dbnamevar <- lookupEnv "DB_NAME"
+  uservar <- lookupEnv "XNOEBLOG_USER"
+  passvar <- lookupEnv "XNOEBLOG_PASS"
+
+  let dbhost = case dbhostvar of
+                Just h -> h
+                Nothing -> "db"
+  let dbuser = case dbuservar of 
+                Just u -> u
+                Nothing -> "root"
+  let dbpass = case dbpassvar of
+                Just p -> p
+                Nothing -> "password"
+  let dbname = case dbnamevar of
+                Just d -> d
+                Nothing -> "xnoeblog"
+
+  let user = case uservar of 
+                Just u -> u
+                Nothing -> ""
+  let pass = case passvar of
+                Just p -> p
+                Nothing -> ""
+
+  c <- connectPostgreSQL ("host=" ++ dbhost ++ " user=" ++ dbuser ++ " password=" ++ dbpass ++ " dbname=" ++ dbname)
 
   createPostsTable <- prepare c "CREATE TABLE IF NOT EXISTS posts(postid serial primary key, catid int, title varchar(128), subtext varchar(128), content text);"
   createCategoriesTable <- prepare c "CREATE TABLE IF NOT EXISTS categories(catid serial primary key, name varchar(128));"
@@ -326,7 +354,23 @@ main = do
   execute createCategoriesTable []
   execute createUsersTable []
   commit c
-  
+
+  queryUser <- prepare c "SELECT * from users WHERE username like ?;"
+  execute queryUser [toSql user]
+  userExists <- fetchAllRows queryUser
+  if user /= "" then
+    case userExists of 
+      [_] -> do return Nothing
+      [] -> do
+        let passwordHashBS = SHA256.hash (C.pack pass)
+        let passwordHash = hexOfBS passwordHashBS
+        createUser <- prepare c "INSERT INTO users(username, password) VALUES(?, ?);"
+        execute createUser [toSql user, toSql passwordHash]
+        commit c
+        return Nothing
+  else
+    do return Nothing
+
   simpleHTTP config $ do
     decodeBody (defaultBodyPolicy "/tmp/" 0 4096 4096)
     msum [ dir "v1" $ dir "post" $ path $ \pid -> require (getPostContent c pid) $ \post -> ok $ toResponse post

backend/backend.cabal

@@ -29,6 +29,6 @@ executable backend
 
     -- LANGUAGE extensions used by modules in this package.
     -- other-extensions:
-    build-depends:    base ^>=4.14.3.0, happstack-server ^>=7.7.2, HDBC ^>= 2.4.0.4, HDBC-postgresql ^>= 2.3.2.4, json ^>= 0.10, bytestring ^>= 0.10.12.0, cryptohash-sha256 ^>= 0.11.102.1, random ^>= 1.1, mtl ^>= 2.2.2
+    build-depends:    base ^>=4.14.3.0, happstack-server ^>=7.7.2, HDBC ^>= 2.4.0.4, HDBC-postgresql ^>= 2.3.2.4, json ^>= 0.10, bytestring ^>= 0.10.12.0, cryptohash-sha256 ^>= 0.11.102.1, random ^>= 1.1, mtl ^>= 2.2.2, read-env-var ^>= 1.0.0.0
     hs-source-dirs:   app
     default-language: Haskell2010

docker-compose.yml

@@ -2,22 +2,29 @@ version: '3.0'
 
 services: 
   frontend:
+    restart: unless-stopped
     build: ./frontend
+    image: registry.xnopyt.com/xnoeblog-frontend:latest
   
   backend:
+    restart: unless-stopped
     build: ./backend
+    image: registry.xnopyt.com/xnoeblog-backend:latest
     depends_on: 
       - database
   
   nginx:
+    restart: unless-stopped
     image: nginx:alpine
     ports:
       - 80:80
     volumes:
       - ./nginx/nginx.conf:/etc/nginx/nginx.conf
 
-  database:
+  db:
+    restart: unless-stopped
     image: postgres
     environment: 
-      - POSTGRES_PASSWORD=root
-      - POSTGRES_USER=blog
+      - POSTGRES_PASSWORD=password
+      - POSTGRES_USER=root
+      - POSTGRES_DB=xnoeblog