Jaume Solà

Setting up an Ethereum node on the Rinkeby testnet

Warning: this worked for me on macOS as of August 2017. Over time you can expect some/most/all of the information here to have changed.

There are several testnets, a number of them old/deprecated. The latest seem to be Kovan and Rinkeby. Kovan seems to work only with Parity while Rinkeby seems to work only with geth.

You will need to install geth first.

I mostly followed this guide.

I tried first the experimental light mode but I got errors, so I tried with the full mode. Not a big deal at this moment because the size on disk is below 1GB and it took around one hour to download/build with a 2011 macbook Air.

I prefer to make the data directory explicit (where the blockchain files will be stored), so I first create one on a disk of my choice. Also I will work from that directory, so I will assume all commands are entered from it.

$ mkdir /path/to/rinkeby
$ cd /path/to/rinkeby

intitalise with genesis block

$ curl -O https://www.rinkeby.io/rinkeby.json $ geth --datadir=. init rinkeby.json

load blockchain 

$ geth --networkid=4 --datadir=. --ethstats='yournode:Respect my authoritah!@stats.rinkeby.io' --bootnodes=enode://a24ac7c5484ef4ed0c5eb2d36620ba4e4aa13b8c84684e1b4aab0cebea2ae45cb4d375b77eab56516d34bfbd3c1a833fc51296ff084b770b94fb9028c4d25ccf@52.169.42.101:30303?discport=30304 --cache=1024

Wait. You will see the INFO message "Block synchronisation started" then many INFO lines starting with "Imported...". Sync is in progress... 

  • Note the 1GB cache, you can use less or more depending on your available memory
  • Network id 4 corresponds to the Rinkeby chain
  • Blockchain data will be stored in geth/

Check blockchain sync progress

While the node is up & running (the above command) you can get info about the blockchain sync progress (among other data) through the JavaScript console. In another terminal window type:

$ cd /path/to/rinkeby
$ geth attach ipc:geth.ipc

At the ">" prompt you can type, e.g.

> eth
> eth.syncing
> adm
> adm.peers

You can double check you are seeing the right data progress by looking at the last block at www.rinkeby.io home page.

Note that the "NOTE...Importing..." messages include a number parameter which is the block being processed.

Getting free (worthless) ether for testing

Create a testing account

Create an account, enter password, get its address (account data will be saved to keystore/):

$ geth --datadir=. account new
...(enter password):..
Address: {559b0e5a899d9ef4c04ee35ccbefab2e6d7f06da}

That is the address I got. In order to use the faucet & get ether into this account, first create a github gist with just the hash in it (remember to prepend with "0x"). In my case:

Now use your gist URL in the faucet feature at www.rinkeby.io

I requested 3 ETH, then I searched etherscan with my address to verify I got them:

https://rinkeby.etherscan.io/address/0x559b0e5a899d9ef4c04ee35ccbefab2e6d7f06da

Next verification step would be to verify that locally we also get the correct balance.

We first verify it is taking the accounts we created (files in keystore/)

> eth.accounts
["0x559b0e5a899d9ef4c04ee35ccbefab2e6d7f06da", "0x62c8681441620cb0574fcee27d6085529067b8da"]

The first one (index 0) is the one I got my 3 ETH, let's see if they are on our local blockchain (balance for account 0):

> web3.fromWei(web3.eth.getBalance(web3.eth.accounts[0]));
3

great!

Now we may keep using geth, or a wallet for a nice UI.

Share a Mercurial repository on github (macOS)

Local macOS configuration

Python & Mercurial

This was tested on macOS El Capitan, with Pyhton 2.7 and Mercurial 4.2.2

Install Hg-Git

You will need the Hg-Git Mercurial plugin.

It can be installed with Python's package installer pip.

Install pip first:

$ wget https://bootstrap.pypa.io/get-pip.py
$ python get-pip.py

Install Mercurial (eventually) & Hg-Git:

$ sudo pip install mercurial
$ sudo pip install hg-git

Enable the extension:

$ vi ~/.hgrc:
[extensions]

hggit =

SSH key for github

create SSH key (details)

  • ssh-keygen -t rsa -b 4096 -C "someone@example.com"

add it to your github account (details)

  • $ pbcopy < ~/.ssh/id_rsa.pub
  • Github: Settings -- SSH / GPG Keys -- New SSH key -- paste clipboard

Configure & share repository

create empty github repository

  • create on github
  • copy its URL
configure local empty repository
$ mkdir myrepo
$ cd myrepo
$ hg init

set username & include github URL as default 
$ vi .hg/hgrc

[ui]
username = Someone Example <someone@example.com>

[paths]
default = git+ssh://git@github.com/someoneaccount/myrepo.git

Push & pull

Upload local changes to github
hg addremove
hg commit
hg bookmark -r default master
hg push

Integrate locally changes made on github

hg pull -u


Looking for a Web Designer and/or Front End developer to join a future startup in Valencia

We are building a team that will participate in the startup acceleration program by Bbooster.

This is an intensive program of 4 months (June to September), at the end of which we expect to get funding (65% of the projects got it in past editions and we believe ours is among the best :-).

Ideally full-time on-site in Valencia as a founder, but we are also open to some other kind of collaboration like part-time or remote.

The project will be an internet portal initially focused in the tourism sector and collaborative economy. 

Current team members have expertise in business, marketing and backend development. We need to cover the graphical design/UI/front end area.

Interested? Contact me on Linkedin

 




Email Round Trip Monitoring

If you administer an email server as I do, it's very useful to have an automated monitoring system that checks often that it works properly.

My first try on any new feature I want to add to my non-fatally-critical systems is to use an external service, specially if it can be done for free. Whereas there is a number of server monitoring services, most don't include roundtrip email monitoring, at least on their free plan. 

The only one I found to include it is...

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