feat(cdc): Prepare the self hosted environment for the Change Data Capture pipeline

.env

@@ -7,3 +7,4 @@ SENTRY_IMAGE=getsentry/sentry:nightly
 SNUBA_IMAGE=getsentry/snuba:nightly
 RELAY_IMAGE=getsentry/relay:nightly
 SYMBOLICATOR_IMAGE=getsentry/symbolicator:nightly
+WAL2JSON_VERSION=latest

.gitignore

@@ -84,3 +84,6 @@ symbolicator/config.yml
 geoip/GeoIP.conf
 geoip/*.mmdb
 geoip/.geoipupdate.lock
+
+# wal2json download
+postgres/wal2json

docker-compose.yml

@@ -71,10 +71,31 @@ services:
   postgres:
     <<: *restart_policy
     image: "postgres:9.6"
+    command: 
+      - "postgres"
+      - "-c" 
+      - "wal_level=logical"
+      - "-c" 
+      - "max_replication_slots=1"
+      - "-c" 
+      - "max_wal_senders=1"
     environment:
       POSTGRES_HOST_AUTH_METHOD: "trust"
+    entrypoint: /cdc/postgres-entrypoint.sh
     volumes:
       - "sentry-postgres:/var/lib/postgresql/data"
+      - type: bind
+        read_only: true
+        source: ./postgres/init_hba.sh
+        target: /docker-entrypoint-initdb.d/init_hba.sh
+      - type: bind
+        read_only: true
+        source: ./postgres/postgres-entrypoint.sh
+        target: /cdc/postgres-entrypoint.sh
+      - type: bind
+        read_only: true
+        source: ./postgres/wal2json/wal2json.so
+        target: /wal2json/wal2json.so
   zookeeper:
     <<: *restart_policy
     image: "confluentinc/cp-zookeeper:5.5.0"

install.sh

@@ -18,6 +18,7 @@ source update-docker-images.sh
 source build-docker-images.sh
 source turn-things-off.sh
 source set-up-zookeeper.sh
+source install-wal2json.sh
 source bootstrap-snuba.sh
 source create-kafka-topics.sh
 source upgrade-postgres.sh

install/install-wal2json.sh

@@ -0,0 +1,31 @@
+echo "${_group}Downloading and installing wal2json ..."
+
+FILE_TO_USE="../postgres/wal2json/wal2json.so"
+ARCH=$(uname -m)
+FILE_NAME="wal2json-Linux-$ARCH.so"
+
+if [[ $WAL2JSON_VERSION == "latest" ]]; then
+    VERSION=$(
+        wget "https://api.github.com/repos/getsentry/wal2json/releases/latest" -O - |
+        grep '"tag_name":' |
+        sed -E 's/.*"([^"]+)".*/\1/'
+    )
+
+    if [[ ! $VERSION ]]; then
+        echo "Cannot find wal2json latest version"
+        exit 1
+    fi
+else
+    VERSION=$WAL2JSON_VERSION
+fi
+
+mkdir -p ../postgres/wal2json
+if [ ! -f "../postgres/wal2json/$VERSION/$FILE_NAME" ]; then
+    mkdir -p "../postgres/wal2json/$VERSION"
+    wget \
+        "https://github.com/getsentry/wal2json/releases/download/$VERSION/$FILE_NAME" \
+        -P "../postgres/wal2json/$VERSION/"
+    ln -s "`pwd`/../postgres/wal2json/$VERSION/$FILE_NAME" "$FILE_TO_USE"
+fi  
+
+echo "${_endgroup}"

postgres/init_hba.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+# Initializes the pg_hba file with access permissions to the replication
+# slots.
+
+set -e
+
+{ echo "host replication all all trust"; } >> "$PGDATA/pg_hba.conf"

postgres/postgres-entrypoint.sh

@@ -0,0 +1,41 @@
+#!/bin/bash
+# This script replaces the default docker entrypoint for postgres in the
+# development environment.
+# Its job is to ensure postgres is properly configured to support the
+# Change Data Capture pipeline (by setting access permissions and installing
+# the replication plugin we use for CDC). Unfortunately the default
+# Postgres image does not allow this level of configurability so we need
+# to do it this way in order not to have to publish and maintain our own
+# Postgres image.
+#
+# This then, at the end, transfers control to the default entrypoint.
+
+set -e
+
+cdc_setup_hba_conf() {
+    # Ensure pg-hba is properly configured to allow connections
+    # to the replication slots.
+
+    PG_HBA="$PGDATA/pg_hba.conf"
+    if [ ! -f "$PG_HBA" ]; then
+        echo "DB not initialized. Postgres will take care of pg_hba"
+    elif [ "$(grep -c -E "^host\s+replication" "$PGDATA"/pg_hba.conf)" != 0 ]; then
+        echo "Replication config already present in pg_hba. Not changing anything."
+    else
+        # Execute the same script we run on DB initialization
+        /docker-entrypoint-initdb.d/init_hba.sh
+    fi
+}
+
+bind_wal2json() {
+    # Create the symlink to wal2json.so
+    ln -sf /wal2json/wal2json.so `pg_config --pkglibdir`/wal2json.so
+}
+
+echo "Setting up Change Data Capture"
+
+if [ "$1" = 'postgres' ]; then
+    cdc_setup_hba_conf
+    bind_wal2json
+fi
+exec /docker-entrypoint.sh "$@"

scripts/bump-version.sh

@@ -8,11 +8,14 @@ OLD_VERSION="$1"
 NEW_VERSION="$2"
 
 SYMBOLICATOR_VERSION=${SYMBOLICATOR_VERSION:-$(curl -s "https://api.github.com/repos/getsentry/symbolicator/releases/latest" | grep -Po '"tag_name": "\K.*?(?=")')}
+WAL2JSON_VERSION=${WAL2JSON_VERSION:-$(curl -s "https://api.github.com/repos/getsentry/wal2json/releases/latest" | grep -Po '"tag_name": "\K.*?(?=")')}
 
 sed -i -e "s/^SYMBOLICATOR_IMAGE=\([^:]\+\):.\+\$/SYMBOLICATOR_IMAGE=\1:$SYMBOLICATOR_VERSION/" .env
+sed -i -e "s/^WAL2JSON_VERSION=\([^:]\+\):.\+\$/WAL2JSON_VERSION=\1:$WAL2JSON_VERSION/" .env
 sed -i -e "s/^\(SENTRY\|SNUBA\|RELAY\)_IMAGE=\([^:]\+\):.\+\$/\1_IMAGE=\2:$NEW_VERSION/" .env
 sed -i -e "s/^\# Self-Hosted Sentry .*/# Self-Hosted Sentry $NEW_VERSION/" README.md
 sed -i -e "s/\(Change Date:\s*\)[-0-9]\+\$/\\1$(date +'%Y-%m-%d' -d '3 years')/" LICENSE
 
 echo "New version: $NEW_VERSION"
 echo "New Symbolicator version: $SYMBOLICATOR_VERSION"
+echo "New wal2json version: $WAL2JSON_VERSION"