This guide goes into details on how to compile and deploy BlockScout instance to work with Polygon-Edge. BlockScout has its own documentation, but this guide focuses on simple but detailed step-by-step instructions on how to setup BlockScout instance.
- Operating System: Ubuntu Server 20.04 LTS download link with sudo permissions
- Server Hardware: 8CPU / 16GB RAM / 50GB HDD (LVM)
- Database Server: Dedicated server with 2 CPU / 4GB RAM / 100GB SSD / PostgreSQL 13.4
The requirement for following this guide is to have a database server ready, database and db user configured. This guide will not go into details on how to deploy and configure PostgreSQL server. There are plenty of guides on now to do this, for example DigitalOcean Guide
This guide is meant only to help you to get BlockScout up and running on a single instance which is not ideal production setup.
For production, you'll probably want to introduce reverse proxy, load balancer, scalability options, etc. into the architecture.
BlockScout Deployment Procedure
Part 1 - install dependencies
Before we start we need to make sure we have all the binaries installed that the blockscout is dependent on.
Update & upgrade system
sudo apt -y update && sudo apt -y upgrade
Add erlang repos
# go to your home dir
# download deb
# download key
# install repo
sudo dpkg -i erlang-solutions_2.0_all.deb
# install key
sudo apt-key add erlang_solutions.asc
# remove deb
# remove key
Add NodeJS repo
sudo curl -sL https://deb.nodesource.com/setup_16.x | sudo -E bash -
sudo curl https://sh.rustup.rs -sSf | sh -s -- -y
Install required version of Erlang
sudo apt -y install esl-erlang=1:24.*
Install required version of Elixir
The version of Elixir must be
1.13. If we try and install this version from the official repo,
erlang will update to
Erlang/OTP 25 and we do not want that.
Because of this, we need to install the specific precompiled
elixir version from GitHub releases page.
sudo unzip -d /usr/local/elixir/ Precompiled.zip
Now we need to properly set up
exlixir system binaries.
sudo ln -s /usr/local/elixir/bin/elixir /usr/local/bin/elixir
sudo ln -s /usr/local/elixir/bin/mix /usr/local/bin/mix
sudo ln -s /usr/local/elixir/bin/iex /usr/local/bin/iex
sudo ln -s /usr/local/elixir/bin/elixirc /usr/local/bin/elixirc
erlang are properly installed by running
This should be the output:
Erlang/OTP 24 [erts-12.3.1] [source] [64-bit] [smp:8:8] [ds:8:8:10] [async-threads:1] [jit]
Elixir 1.13.4 (compiled with Erlang/OTP 22)
Erlang/OTP must be version
Elixir must be version
If that is not the case, you will run into issues with compiling BlockScout and/or running it.
Check out the official BlockScout requirements page
sudo apt -y install nodejs
sudo apt -y install cargo
Install other dependencies
sudo apt -y install automake libtool inotify-tools gcc libgmp-dev make g++ git
Optionally install postgresql client to check your db connection
sudo apt install -y postgresql-client
Part 2 - set environment variables
We need to set the environment variables, before we begin with BlockScout compilation. In this guide we'll set only the basic minimum to get it working. Full list of variables that can be set you can find here
Set database connection as environment variable
# postgresql connection example: DATABASE_URL=postgresql://blockscout:[email protected]:5432/blockscout
export DATABASE_URL=postgresql://<db_user>:<db_pass>@<db_host>:<db_port>/<db_name> # db_name does not have to be existing database
# we set these env vars to test the db connection with psql
export PGDATABASE=postgres # on AWS RDS postgres database is always created
Now test your DB connection with provided parameters. Since you've provided PG env vars, you should be able to connect to the database only by running:
If the database is configured correctly, you should see a psql prompt:
psql (12.9 (Ubuntu 12.9-0ubuntu0.20.04.1))
SSL connection (protocol: TLSv1.3, cipher: TLS_AES_256_GCM_SHA384, bits: 256, compression: off)
Type "help" for help.
Otherwise, you might see an error like this:
psql: error: FATAL: password authentication failed for user "blockscout"
FATAL: password authentication failed for user "blockscout"
If this is the case these docs might help you.
Make sure you've sorted out all db connection issues before proceeding to the next part. You'll need to provide superuser privileges to blockscout user.
[email protected]:~$ createuser --interactive
Enter name of role to add: blockscout
Shall the new role be a superuser? (y/n) y
Part 3 - clone and compile BlockScout
Now we finally get to start the BlockScout installation.
Clone BlockScout repo
git clone https://github.com/Trapesys/blockscout
Generate secret key base to protect production build
mix local.rebar --force
At the very last line, you should see a long string of random characters.
This should be set as your
SECRET_KEY_BASE environment variable, before the next step.
Set production mode
Cd into clone directory and start compiling
mix local.hex --force
mix do deps.get, local.rebar --force, deps.compile, compile
If you have deployed previously, remove static assets from the previous build mix phx.digest.clean.
This part will fail if you didn't set up your DB connection properly, you didn't provide, or you've defined wrong parameters at DATABASE_URL environment variable. The database user needs to have superuser privileges.
mix do ecto.create, ecto.migrate
If you need to drop the database first, run
mix do ecto.drop, ecto.create, ecto.migrate
Install npm dependencies and compile frontend assets
You need to change directory to the folder which contains frontend assets.
sudo npm install
sudo node_modules/webpack/bin/webpack.js --mode production
Compilation of these assets can take a few minutes, and it will display no output.
It can look like the process is stuck, but just be patient.
When compile process is finished, it should output something like:
webpack 5.69.1 compiled with 3 warnings in 104942 ms
Build static assets
For this step you need to return to the root of your BlockScout clone folder.
sudo mix phx.digest
Generate self-signed certificates
You can skip this step if you won't use
mix phx.gen.cert blockscout blockscout.local
Part 4 - create and run BlockScout service
In this part we need to set up a system service as we want BlockScout to run in the background and persist after system reboot.
Create service file
sudo touch /etc/systemd/system/explorer.service
Edit service file
Use your favorite linux text editor to edit this file and configure the service.
sudo vi /etc/systemd/system/explorer.service
The contents of the explorer.service file should look like this:
Enable starting service on system boot
sudo systemctl daemon-reload
sudo systemctl enable explorer.service
Move your BlockScout clone folder to system-wide location
BlockScout service needs to have access to the folder you've cloned from BlockScout repo and compiled all the assets.
sudo mv ~/blockscout /usr/local
Create env vars file which will be used by BlockScout service
sudo touch /usr/local/blockscout/env_vars.env
# use your favorite text editor
sudo vi /usr/local/blockscout/env_vars.env
# env_vars.env file should hold these values ( adjusted for your environment )
ETHEREUM_JSONRPC_HTTP_URL="localhost:8545" # json-rpc API of the chain
ETHEREUM_JSONRPC_TRACE_URL="localhost:8545" # same as json-rpc API
DATABASE_URL='postgresql://blockscout:[email protected]:5432/blockscout' # database connection from Step 2
SECRET_KEY_BASE="912X3UlQ9p9yFEBD0JU+g27v43HLAYl38nQzJGvnQsir2pMlcGYtSeRY0sSdLkV/" # secret key base
ETHEREUM_JSONRPC_WS_URL="ws://localhost:8545/ws" # websocket API of the chain
CHAIN_ID=93201 # chain id
HEART_COMMAND="systemctl restart explorer" # command used by blockscout to restart it self in case of failure
SUBNETWORK="Supertestnet PoA" # this will be in html title
LOGO="/images/polygon_edge_logo.svg" # logo location
LOGO_FOOTER="/images/polygon_edge_logo.svg" # footer logo location
COIN="EDGE" # coin
COIN_NAME="EDGE Coin" # name of the coin
INDEXER_DISABLE_BLOCK_REWARD_FETCHER="true" # disable block reward indexer as Polygon Edge doesn't support tracing
INDEXER_DISABLE_PENDING_TRANSACTIONS_FETCHER="true" # disable pending transactions indexer as Polygon Edge doesn't support tracing
INDEXER_DISABLE_INTERNAL_TRANSACTIONS_FETCHER="true" # disable internal transactions indexer as Polygon Edge doesn't support tracing
MIX_ENV="prod" # run in production mode
BLOCKSCOUT_PROTOCOL="http" # protocol to run blockscout web service on
PORT=4000 # port to run blockscout service on
DISABLE_EXCHANGE_RATES="true" # disable fetching of exchange rates
POOL_SIZE=200 # the number of database connections
POOL_SIZE_API=300 # the number of read-only database connections
ECTO_USE_SSL="false" # if protocol is set to http this should be false
HEART_BEAT_TIMEOUT=60 # run HEARTH_COMMAND if heartbeat missing for this amount of seconds
INDEXER_MEMORY_LIMIT="10Gb" # soft memory limit for indexer - depending on the size of the chain and the amount of RAM the server has
FETCH_REWARDS_WAY="manual" # disable trace_block query
INDEXER_EMPTY_BLOCKS_SANITIZER_BATCH_SIZE=1000 # sanitize empty block in this batch size
SECRET_KEY_BASE you've generated in Part 3.
Save the file and exit.
Finally, start BlockScout service
sudo systemctl start explorer.service
Part 5 - test out the functionality of your BlockScout instance
Now all that's left to do is to check if BlockScout service is running. Check service status with:
sudo systemctl status explorer.service
To check service output:
sudo journalctl -u explorer.service -f
You can check if there are some new listening ports:
# if netstat is not installed
sudo apt install net-tools
sudo netstat -tulpn
You should get a list of listening ports and on the list there should be something like this:
tcp 0 0 0.0.0.0:5432 0.0.0.0:* LISTEN 28142/postgres
tcp 0 0 0.0.0.0:4000 0.0.0.0:* LISTEN 42148/beam.smp
BlockScout web service runs the port and protocol defined in env file. In this example it runs on
If everything is ok, you should be able to access the BlockScout web portal with
For best performance, it is advisable to have a dedicated/local
polygon-edge full archive non-validator node
that will be used exclusively for BlockScout queries.
json-rpc API of this node, doesn't need to be exposed publicly, as BlockScout runs all queries from the backend.
We've just deployed a single BlockScout instance, which works fine, but for production you should consider placing this instance behind a reverse proxy like Nginx. You should also think about database and instance scalability, depending on your use case.
You should definitely check out the official BlockScout documentation as there a lot of customisation options.