Support multiple DATABASE_URLs (#109)

* Entrypoint: move some variable definitions & reuse where possible * Entrypoint: tiny formatting & consistency tweaks * Entrypoint: refactor some parts into functions (needed for later) * Entrypoint: support `DATABASE_URLS` with comma separated list of urls * Add readme entry mentioning `DATABASE_URLS` * minor cleanup --------- Co-authored-by: Jeff Lambert <[email protected]>
edoburu · Feb 28, 2025 · cea2cf8 · cea2cf8
1 parent 36ac8ff
commit cea2cf8
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diff --git a/README.md b/README.md
@@ -41,12 +41,22 @@ docker run --rm \
     edoburu/pgbouncer
 ```
 
-Connecting should work as expected:
+During startup we'll generate the necessary `userlist.txt` & `pgbouncer.ini` entries to match this information. Connecting should work as expected:
 
 ```sh
 psql 'postgresql://user:pass@localhost/dbname'
 ```
 
+> [!NOTE]
+> If you need quick multi-user setup you can use `DATABASE_URLS` (instead of `DATABASE_URL`) with a comma (`,`) separated list of URLs.
+>
+> ```sh
+> docker run --rm \
+>     -e DATABASE_URLS="postgres://foo:123@postgres-host/foo,postgres://bar:456@postgres-host/bar" \
+>     -p 5432:5432 \
+>     edoburu/pgbouncer
+> ```
+
 Configuration
 -------------
 

diff --git a/entrypoint.sh b/entrypoint.sh
@@ -7,75 +7,115 @@ set -e
 # https://pgbouncer.github.io/config.html
 
 PG_CONFIG_DIR=/etc/pgbouncer
+PG_CONFIG_FILE="${PG_CONFIG_DIR}/pgbouncer.ini"
+_AUTH_FILE="${AUTH_FILE:-$PG_CONFIG_DIR/userlist.txt}"
+
+# Workaround userlist.txt missing issue
+# https://github.com/edoburu/docker-pgbouncer/issues/33
+if [ ! -e "${_AUTH_FILE}" ]; then
+  touch "${_AUTH_FILE}"
+fi
 
-if [ -n "$DATABASE_URL" ]; then
+# Extract all info from a given URL. Sets variables because shell functions can't return multiple values.
+#
+# Parameters:
+#   - The url we should parse
+# Returns (sets variables): DB_USER, DB_PASSWORD, DB_HOST, DB_PORT, DB_NAME
+function parse_url() {
   # Thanks to https://stackoverflow.com/a/17287984/146289
 
   # Allow to pass values like dj-database-url / django-environ accept
-  proto="$(echo $DATABASE_URL | grep :// | sed -e's,^\(.*://\).*,\1,g')"
-  url="$(echo $DATABASE_URL | sed -e s,$proto,,g)"
+  proto="$(echo $1 | grep :// | sed -e's,^\(.*://\).*,\1,g')"
+  url="$(echo $1 | sed -e s,$proto,,g)"
 
   # extract the user and password (if any)
-  userpass=$(echo $url | grep @ | sed -r 's/^(.*)@([^@]*)$/\1/')
+  userpass="$(echo $url | grep @ | sed -r 's/^(.*)@([^@]*)$/\1/')"
   DB_PASSWORD="$(echo $userpass | grep : | cut -d: -f2)"
-  if [ -n "$DB_PASSWORD" ]; then
-    DB_USER=$(echo $userpass | grep : | cut -d: -f1)
+  if [ -n "${DB_PASSWORD}" ]; then
+    DB_USER="$(echo $userpass | grep : | cut -d: -f1)"
   else
-    DB_USER=$userpass
+    DB_USER="${userpass}"
   fi
 
   # extract the host -- updated
   hostport=`echo $url | sed -e s,$userpass@,,g | cut -d/ -f1`
   port=`echo $hostport | grep : | cut -d: -f2`
   if [ -n "$port" ]; then
     DB_HOST=`echo $hostport | grep : | cut -d: -f1`
-    DB_PORT=$port
+    DB_PORT="${port}"
   else
-    DB_HOST=$hostport
+    DB_HOST="${hostport}"
   fi
 
   DB_NAME="$(echo $url | grep / | cut -d/ -f2-)"
-fi
+}
+
+# Grabs variables set by `parse_url` and adds them to the userlist if not already set in there.
+function generate_userlist_if_needed() {
+  if [ -n "${DB_USER}" -a -n "${DB_PASSWORD}" -a -e "${_AUTH_FILE}" ] && ! grep -q "^\"${DB_USER}\"" "${_AUTH_FILE}"; then
+    if [ "${AUTH_TYPE}" == "plain" ] || [ "${AUTH_TYPE}" == "scram-sha-256" ]; then
+      pass="${DB_PASSWORD}"
+    else
+      pass="md5$(echo -n "${DB_PASSWORD}${DB_USER}" | md5sum | cut -f 1 -d ' ')"
+    fi
+    echo "\"${DB_USER}\" \"${pass}\"" >> "${_AUTH_FILE}"
+    echo "Wrote authentication credentials for '${DB_USER}' to ${_AUTH_FILE}"
+  fi
+}
+
+# Grabs variables set by `parse_url` and adds them to the PG config file as a database entry.
+function generate_config_db_entry() {
+  printf "\
+${DB_NAME:-*} = host=${DB_HOST:?"Setup pgbouncer config error! You must set DB_HOST env"} \
+port=${DB_PORT:-5432} auth_user=${DB_USER:-postgres}
+${CLIENT_ENCODING:+client_encoding = ${CLIENT_ENCODING}\n}\
+" >> "${PG_CONFIG_FILE}"
+}
 
 # Write the password with MD5 encryption, to avoid printing it during startup.
 # Notice that `docker inspect` will show unencrypted env variables.
-_AUTH_FILE="${AUTH_FILE:-$PG_CONFIG_DIR/userlist.txt}"
-
-# Workaround userlist.txt missing issue
-# https://github.com/edoburu/docker-pgbouncer/issues/33
-if [ ! -e "${_AUTH_FILE}" ]; then
-  touch "${_AUTH_FILE}"
-fi
-
-if [ -n "$DB_USER" -a -n "$DB_PASSWORD" -a -e "${_AUTH_FILE}" ] && ! grep -q "^\"$DB_USER\"" "${_AUTH_FILE}"; then
-  if [ "$AUTH_TYPE" == "plain" ] || [ "$AUTH_TYPE" == "scram-sha-256" ]; then
-    pass="$DB_PASSWORD"
-  else
-    pass="md5$(echo -n "$DB_PASSWORD$DB_USER" | md5sum | cut -f 1 -d ' ')"
+if [ -n "${DATABASE_URLS}" ]; then
+  echo "${DATABASE_URLS}" | tr , '\n' | while read url; do
+    parse_url "$url"
+    generate_userlist_if_needed
+  done
+else
+  if [ -n "${DATABASE_URL}" ]; then
+    parse_url "${DATABASE_URL}"
   fi
-  echo "\"$DB_USER\" \"$pass\"" >> ${PG_CONFIG_DIR}/userlist.txt
-  echo "Wrote authentication credentials to ${PG_CONFIG_DIR}/userlist.txt"
+  generate_userlist_if_needed
 fi
 
-if [ ! -f ${PG_CONFIG_DIR}/pgbouncer.ini ]; then
+if [ ! -f "${PG_CONFIG_FILE}" ]; then
   echo "Creating pgbouncer config in ${PG_CONFIG_DIR}"
 
-# Config file is in "ini" format. Section names are between "[" and "]".
-# Lines starting with ";" or "#" are taken as comments and ignored.
-# The characters ";" and "#" are not recognized when they appear later in the line.
+  # Config file is in "ini" format. Section names are between "[" and "]".
+  # Lines starting with ";" or "#" are taken as comments and ignored.
+  # The characters ";" and "#" are not recognized when they appear later in the line.
   printf "\
 ################## Auto generated ##################
 [databases]
-${DB_NAME:-*} = host=${DB_HOST:?"Setup pgbouncer config error! You must set DB_HOST env"} \
-port=${DB_PORT:-5432} auth_user=${DB_USER:-postgres}
-${CLIENT_ENCODING:+client_encoding = ${CLIENT_ENCODING}\n}\
+" > "${PG_CONFIG_FILE}"
+
+  if [ -n "$DATABASE_URLS" ]; then
+    echo "$DATABASE_URLS" | tr , '\n' | while read url; do
+      parse_url "$url"
+      generate_config_db_entry
+    done
+  else
+    if [ -n "$DATABASE_URL" ]; then
+      parse_url "$DATABASE_URL"
+    fi
+    generate_config_db_entry
+  fi
 
+  printf "\
 [pgbouncer]
 listen_addr = ${LISTEN_ADDR:-0.0.0.0}
 listen_port = ${LISTEN_PORT:-5432}
 unix_socket_dir = ${UNIX_SOCKET_DIR}
 user = postgres
-auth_file = ${AUTH_FILE:-$PG_CONFIG_DIR/userlist.txt}
+auth_file = ${_AUTH_FILE}
 ${AUTH_HBA_FILE:+auth_hba_file = ${AUTH_HBA_FILE}\n}\
 auth_type = ${AUTH_TYPE:-md5}
 ${AUTH_USER:+auth_user = ${AUTH_USER}\n}\
@@ -154,9 +194,9 @@ ${TCP_KEEPIDLE:+tcp_keepidle = ${TCP_KEEPIDLE}\n}\
 ${TCP_KEEPINTVL:+tcp_keepintvl = ${TCP_KEEPINTVL}\n}\
 ${TCP_USER_TIMEOUT:+tcp_user_timeout = ${TCP_USER_TIMEOUT}\n}\
 ################## end file ##################
-" > ${PG_CONFIG_DIR}/pgbouncer.ini
-cat ${PG_CONFIG_DIR}/pgbouncer.ini
-echo "Starting $*..."
+" >> "${PG_CONFIG_FILE}"
+  cat "${PG_CONFIG_FILE}"
 fi
 
+echo "Starting $*..."
 exec "$@"