small medium large xlarge

The latest version of the book is P1.0, released 11 months ago. If you've bought a PDF of the book and would like to update it to this version (for free), visit your home page.

By default this page displays the errata for the latest version of the book. If you have a previous version, select it here:

If you've found a new error, please submit it.

  • Typo
  • Tech. error
  • Suggestion
  • Maybe next edition
  • Not a problem
  • Reported in: B9.0 (18-Jan-19)
#84320
PDF page: NA
Paper page: NA
In Part 1, section 1, "Generating a Rails App without Ruby Installed", there is the command: $ docker run -i -t --rm -v ${pwd}:/usr/src/app ruby:2....more...
  • Reported in: P1.0 (12-May-19)
#85085
Paper page: 4
For MacOS users that have brew installed, you can also do "brew cask install docker", and you will be setup. I would like to see this added after the ...more...
  • Reported in: P1.0 (13-Dec-19)
#86147
Paper page: 22
For Rails 6+ you need to install recent version of Yarn and run a rails webpacker:install. Edit the Dockerfile like suggested bellow, and everything r...more...
  • Reported in: P1.0 (21-Feb-19)
#84602
PDF page: 25
I'm using MacOS 10.13.2 with Docker Desktop 2.0.0.0-mac81 After following all the steps, and attempting the 'docker run' command for the first time...more...
  • Reported in: P1.0 (26-Feb-19)
#84618
PDF page: 25
Due to release of sqlite3 1.4.0, Rails 5.2.2 ActiveRecord sqlite3 adapter requires 1.3.x and fails to work with sqlite3 1.4.0, though a new Rails appl...more...
  • Reported in: P1.0 (01-Mar-19)
#84626
PDF page: 25
Following the instructions, I've built a Dockerfile, built the image, and asked it to run using the $ docker run line shown n the middle of the page (...more...
  • Reported in: P1.0 (30-Jun-19)
#85494
PDF page: 25
with Docker 18. 09.2 on the Mac it looks like the "-t" option is required to show command output without buffering. $ docker run -t -p 3000:3000 ...more...
  • Reported in: P1.0 (08-Mar-19)
#84656
PDF page: 27
I had to login to Docker before docker-compose would work for me. Prior to that I got: dockerpycreds.errors.StoreError: Credentials store docker-cr...more...
  • Reported in: P1.0 (10-Mar-19)
#84669
PDF page: 28

Last line of the page:

“all IPv4 address on this machine.”

should be

"“all IPv4 addresses on this machine.”
--James Ludlow

  • Reported in: P1.0 (25-Feb-19)
#84611
PDF page: 38
"This tells Docker to copy all the files from our local, current directory ( . ) into /usr/src/app on the filesystem of the new image. Since our loca...more...
  • Reported in: B9.0 (24-Jan-19)
#84355
PDF page: 39

"If you look through the output, you’ll see that steps 1 to 3 all say Using cache ."

Actually, only step 2 says that.--Angelos Orfanakos

  • Reported in: P1.0 (09-Mar-19)
#84661
PDF page: 40
Gemfile.lock is mentioned as already existing but I carefully followed all steps and there is no Gemfile.lock To create Gemfile.lock, I did this...more...
  • Reported in: B9.0 (25-Jan-19)
#84358
PDF page: 46

On the 13th line, "collection" should be "mapping".--Angelos Orfanakos

  • Reported in: B9.0 (22-Dec-18)
#84162
PDF page: 46
1. You fail to explicitly mention to go ahead and create docker-compose.yml 2. If creating docker-compose.yml with textmate it is very difficult to...more...
  • Reported in: P1.0 (14-Mar-19)
#84691
PDF page: 47

$stdout.sync = true

should be

STDOUT.sync = true--james

  • Reported in: B9.0 (25-Jan-19)
#84359
PDF page: 54

In the last terminal session, the command should be `docker run`--Angelos Orfanakos

  • Reported in: P1.0 (08-Jul-19)
#85530
PDF page: 56
When "Connecting Our Rails App to Postgres" and utilizing the env files. running the command 'docker-compose​​ ​​run​​ ​​--rm​​ ​​web​​ ​​bin/rails...more...
  • Reported in: B9.0 (26-Jan-19)
#84364
PDF page: 59

6th line, "Ruby server" should be "Rails server"--Angelos Orfanakos

  • Reported in: B10.0 (17-Feb-19)
#84588
PDF page: 64
Paper page: 49

In the light green Info box, the line
"See Chapter 9 for more details."
should be
"See Chapter 10 for more details."--Stephen Giles

  • Reported in: P1.0 (09-Jan-20)
#86239
PDF page: 64
Paper page: 50
A server is already running error at this point can't be solved by deleting tmp/pids/server.pid on the local machine because at this point, the server...more...
  • Reported in: B10.0 (17-Feb-19)
#84589
PDF page: 65
Paper page: 50

In the green info box the same erratum as before:
the reference to Chapter 9 should be Chapter 10--Stephen Giles

  • Reported in: B8.0 (24-Nov-18)
#83952
Paper page: 65
The command should be `docker-compose up -d` instead of `docker-compose up -d web`. Since in the previous section where we install the redis gem we di...more...
  • Reported in: B10.0 (17-Feb-19)
#84590
PDF page: 66
Paper page: 51

Same as the last two.
The green info box refers to Chapter 9 instead of Chapter 10.--Stephen Giles

  • Reported in: B9.0 (01-Jan-19)
#84219
PDF page: 66
Using Redis.new in the controller will start a new Redis connection every time for every request. This will not scale well. The solution is to create ...more...
  • Reported in: P1.0 (19-Mar-19)
#84699
PDF page: 79
if set, it uses the value of the POSTGRES_DB environment variable as the name for this table should be: if set, it uses the value of the POSTGRE...more...
  • Reported in: B9.0 (08-Jan-19)
#84283
PDF page: 82
docker-compose rm -f database fails because you have saved changes in the docker-compose.yml file that are invalid. Better is to stop the database and...more...
  • Reported in: P1.0 (14-Sep-19)
#85804
PDF page: 84
Postgres named volume added users created Once postgres container deleted and new one run Rails is asking to run migration. I followed all steps,...more...
  • Reported in: B9.0 (27-Jan-19)
#84377
PDF page: 89
In the Dockerfile, tee is not really necessary since we're running the command as root (it's not prefixed with sudo). We can use a regular redirection...more...
  • Reported in: B9.0 (27-Jan-19)
#84378
PDF page: 90

The "docker run" commands can take a "--rm" option to use throwaway containers.--Angelos Orfanakos

  • Reported in: P1.0 (02-Mar-19)
#84635
PDF page: 90
Running "docker-compose build web" on my Mac OSX 10.13.6 emits a warning about line 13 of the Dockerfile: Warning: apt-key output should not be pa...more...
  • Reported in: P1.0 (06-Jul-19)
#85520
PDF page: 100
I got the following error when executing: $ docker-compose exec web rspec spec/system/ --------------------------------------------------------...more...
  • Reported in: B10.0 (30-Jan-19)
#84398
PDF page: 100
"Create the file spec/system/page_views_spec.rb and edit it to look as follows: Let’s start with this:" The second sentence should be removed.--...more...
  • Reported in: B10.0 (30-Jan-19)
#84399
PDF page: 100

"Linux Users: File Ownership" We have not Rails-generated anything here, I'm not sure we need to chown anything.--Angelos Orfanakos

  • Reported in: B10.0 (04-Feb-19)
#84449
PDF page: 102
from: ``` expect(page).to have_text("ENHANCED!") ``` to: ``` expect(page).to have_text(:all, "ENHANCED!") ``` When I ran the test without `:al...more...
  • Reported in: B10.0 (30-Jan-19)
#84400
PDF page: 104

Not sure we need to chown anything here since we did not generate anything with Rails.--Angelos Orfanakos

  • Reported in: P1.0 (29-Dec-19)
#86195
PDF page: 106
When I try to run the system tests with JS as per your instructions, I get: Selenium::WebDriver::Error::WebDriverError: Unable to find...more...
  • Reported in: B10.0 (31-Jan-19)
#84410
PDF page: 115
6th line .../gems here is misleading as someone may easily think it refers to a gems directory in the parent directory. I suggest removing the ... her...more...
  • Reported in: P1.0 (20-Mar-19)
#84702
PDF page: 115
When using the Gem Cache Volume, the following command no longer works: "docker-compose exec web rspec spec/system/", because rspec no longer lives i...more...
  • Reported in: B8.0 (25-Nov-18)
#83972
PDF page: 117
Paper page: 106
Hello, I run this command $ docker-compose run --service-ports web to start debugging. But the output says Cannot render console from 172.19.0.1...more...
  • Reported in: P1.0 (14-Sep-19)
#85802
PDF page: 120
Postgres named volume. Asking to run migration after container deleted and recreated. I followed all steps, added named volume to my database service...more...
  • Reported in: B10.0 (17-Feb-19)
#84591
PDF page: 122
Paper page: 110

Another green info box referring to Chapter 9 instead of Chapter 10--Stephen Giles

  • Reported in: B10.0 (31-Jan-19)
#84411
PDF page: 122

Code sample can use `rm -f` to avoid the need to check for the file.

Same thing on page 123.--Angelos Orfanakos

  • Reported in: B10.0 (31-Jan-19)
#84412
PDF page: 123
Last sentence of last paragraph does not add anything knew since we have already added an ENTRYPOINT in our Dockerfile on page 122 (bullet point 3)--A...more...
  • Reported in: B9.0 (29-Nov-18)
#84024
PDF page: 133
The docker-entrypoint.sh script should really start with "#!/usr/bin/env bash", as it uses bash-specific syntax, and /bin/sh is not always symlinked t...more...
  • Reported in: P1.0 (11-May-19)
#85072
PDF page: 147
I'm using Rails v.6.0.0.rc1 bin/rails assets:precompile fails when I'm issuing command `docker build -f Dockerfile.production -t prepin/ipakb:f01` ...more...
  • Reported in: B9.0 (28-Nov-18)
#84003
PDF page: 151
To build prod tag image the following command is given : docker build -f Dockerfile.prod -t robisenberg/myapp_web:prod . Which, at least for me,...more...
Rob Isenberg says: Hi, I'm afraid I'm not seeing this in my version - not sure what the difference is. Would welcome some more details if you have (although the book is going to print shortly).
  • Reported in: P1.0 (23-Apr-19)
#84966
PDF page: 151
We previously removed RUN bundle install from the Dockerfile when discussing gem caches. The production image isn't going to build properly, bec...more...
  • Reported in: P1.0 (22-Mar-19)
#84721
PDF page: 151
So, while trying to build Dockerfile.prod, i ended up failing, because the .env environment variables are not loaded, and asset:precompile initialize ...more...
  • Reported in: P1.0 (11-May-19)
#85073
PDF page: 166
$ docker stack deploy -c docker-stack.yml myapp if we are using private repo, it is required to add --with-registry-auth key, otherwise docker would ...more...
  • Reported in: B10.0 (18-Feb-19)
#84595
PDF page: 171
``` curl -4 http :// localhost :3000 / welcome ``` should not use `localhost` since we are using a local swarm backed by virtualbox instance. Perh...more...
  • Reported in: P1.0 (30-Apr-19)
#84999
PDF page: 172
When adding netcat to RUN apt-get, docker does not like the comment on the same line following the line continuation slash; it treats the next line as...more...
  • Reported in: B9.0 (30-Nov-18)
#84038
PDF page: 172
The db-creator and db-migrator entries need to be added as children of the services key, but this is not clear from the text. Adding them as root elem...more...
  • Reported in: P1.0 (20-Feb-19)
#84601
PDF page: 174
Running command: ``` docker-machine create \ --driver digitalocean \ --digitalocean-access-token $DIGITAL_OCEAN_TOKEN \ --digitalocean-region lo...more...
  • Reported in: B10.0 (03-Feb-19)
#84434
PDF page: 174

"Put this in your .bash_rc file or equivalent"

It's .bashrc (without an underscore)--Angelos Orfanakos

  • Reported in: B9.0 (15-Jan-19)
#84308
PDF page: 177
Paper page: 177
On page 179, when I run the command 'docker-compose build web' I get the follow error after having updated my Dockerfile like page 177 suggest: macbo...more...
  • Reported in: B10.0 (03-Feb-19)
#84435
PDF page: 179

Last line, Dockerhost should be Docker host--Angelos Orfanakos

  • Reported in: B10.0 (03-Feb-19)
#84436
PDF page: 195
"We’re currently maintaining two files in Compose format: docker-compose.yml and docker-compose.prod.yml" The latter should probably be "docker-sta...more...
  • Reported in: P1.0 (22-Apr-19)
#84958
Paper page: 288
The alternative way to see the hostname change in the welcome page using the curl command does not work, since the app is not on localhost but on the ...more...
  • Reported in: B9.0 (18-Jan-19)
#84322
PDF page: 522
This is an extension to #84003 originally submitted by Thomas Battiston. Apparently the issue is related to the command for precompiling assets, requi...more...