Docker Invalid Reference Format: Causes and Fixes

Docker Invalid Reference Format: Causes And Fixes

Docker invalid reference format is an error in docker that permits you to know that your syntax of the docker container picture identify is incorrect. However, you shouldn’t confuse this error with docker being unable to find your picture within the registry.Docker Invalid Reference Format Causes And

If you get this error docker is not going to even go so far as trying up your picture within the registry. Read on to search out out what causes this error and how one can resolve it.

Why Am I Getting The Docker Invalid Reference Format Error?

You are triggering this docker invalid reference format error is that the syntax you might be utilizing on your docker picture is incorrect. You will get this error if docker sees one thing surprising within the picture identify. This could be an invalid area or character earlier than any of your choices.

Here are a number of the most typical triggers of this error in docker:

  • Ending the identify of your docker container picture with a colon like this “program:”
  • Using a splash (-) on the finish of your container picture
  • Also, for those who use a variable like “program:$first” however you haven’t set “first”
  • Using colon greater than as soon as in your docker identify like this “program:1.10:2”
  • Mixing up the order of command line arguments permits one other argument to imagine the position of your picture identify.

A better inspection of this error reveals that the identify you equipped as a docker identify is invalid. That is to say, the docker identify you might be offering to the docker command is unacceptable. In Docker, a reference refers to a pointer for a picture.

Therefore, everytime you cross the picture identify in a docker command, will probably be parsed. When parsing, one of many issues the command will verify is if the identify follows particular Docker guidelines. If the picture identify doesn’t, Docker will set off the error in query.

Depending on the platform you might be utilizing, for those who use the incorrect syntax in your docker picture identify, you’ll set off this error. Below are a number of the variations relying in your working system and your use:

  • docker: invalid reference format home windows
  • docker: invalid reference format mac
  • docker pull invalid reference format
  • docker: invalid reference format ubuntu
  • docker: invalid reference format pwd
  • docker: invalid reference format quantity
  • docker-compose invalid reference format
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– Not Meeting Standard DNS Rules

In docker, the identify of a picture consists of slash-separated identify elements and an non-obligatory registry hostname. When you embrace the hostname, it should meet the usual DNS guidelines. Not assembly the usual of DNS guidelines outcomes on this error.1674227286 352 Docker Invalid Reference Format Causes And

Including the port quantity could also be non-obligatory. If you do not need a hostname, docker normally dockers by default makes use of its registry.

Docker permits names to comprise lowercase letters, separators, and digits. In docker, a separator refers to a interval, 1 or 2 dashes, or 1 or 2 underscores. However, your picture identify can not start or finish with a separator.

Docker additionally requires a tag to use legitimate ASCII. Just like a picture identify, a tag can not start with a splash or interval. With docker, it’s potential to group photographs utilizing their identify and tags. If you might be new to Docker, a tag is a section that follows the colon in a docker picture identify. At this level, it’s price mentioning that it isn’t a should to provide a tag when tagging photographs.

– Use of Uppercase Letters

Suppose you need to create a docker picture by the identify sda-docker-Demo and you employ the next docker command:

docker construct -t sda-docker-Demo

Notice that one character of the picture identify is in uppercase. If you run this command, the output might be an invalid argument “sda-docker-Demo” for “-t, –tag” docker: invalid reference format: repository identify have to be lowercase.

As properly, for those who use the docker run command and embrace an uppercase character in your picture identify, you’ll set off the identical error. Here is how you need to use this command in Docker despite the fact that doing this with this identify will set off the error:

docker run -p 80:80 sda-docker-Demo

– Use of Special Characters

Now, suppose you need to create a docker picture however you need to embrace particular characters to the identify. This is now incorrect per se. However, for those who use these particular characters to begin or finish the identify of your docker picture, you’ll set off the error in query.

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Suppose for this instance’s sake you need to use a particular character on the finish of the docker picture identify. Here is how one can attempt to construct a picture in docker whose identify has a particular character on the finish.

docker construct -t sda-docker-demo-

How To Solve the Docker Invalid Reference Format Error

You can resolve the Docker Invalid Reference Format error by avoiding the usage of particular characters in the beginning and finish of your docker picture names. However, the answer to this error will range relying on what triggered it within the first place.

In the next paragraphs, you’ll learn the assorted methods you’ll be able to resolve this error relying on its root trigger.

– Solution 1: Avoid Using Uppercase Characters in Docker Image

One of a very powerful guidelines relating to naming your docker picture is to all the time use lowercase letters with out areas. In this case, if you wish to resolve the error in your first instance that raises from utilizing an uppercase letter, you’ll be able to accomplish this as follows.

Suppose you need to construct a docker picture by the identify sda-docker-Demo, you’ll be able to accomplish this by ensuring your docker picture identify is in lowercase and utilizing the next docker command: “docker build -t sda-docker-demo”. Also, you need to use the docker run command as follows to perform the identical factor: “docker run -p 80:80 sda-docker-demo”.

– Solution 2: Be Careful When Splitting Long Docker Commands

In case you discover your docker command turning into too lengthy. You can break up it into various traces. However, you have to be cautious when utilizing the foundations beneath relying on the shell (cmd, PowerShell, bash/sh) you’ve in your pc.1674227287 578 Docker Invalid Reference Format Causes And

  • cmd – the multiline escape character is ^
  • powershell – in case you are utilizing PowerShell, then use ` because the multiline escape character
  • bash/sh – for sh/bash use as your multiline escape character
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Here is a fast have a look at how one can accomplish this throughout numerous shells. If you might be on cmd, right here is how one can write a multiline docker command with out triggering the reference format error.

docker construct ^

-t ^

sda-docker-demo

If you might be on PowerShell, your docker command will look one thing like this:

docker construct `

-t `

sda-docker-demo

Lastly, in case you are utilizing sh/bash, your multiline docker command for creating your docker picture will look one thing like this:

docker construct

-t

sda-docker-demo

– Solution 3: Be Careful When Using ${Pwd} And $(Pwd) Path

In case your docker command makes use of ${pwd} then you definitely have to be cautious when utilizing ${pwd} and $(pwd) relying on the shell you might be utilizing. Below is a fast have a look at how one can safely use ${pwd} on completely different shells.

Suppose you might be utilizing ${pwd} or $(pwd) on PowerShell then your command will look one thing like this: “docker run-p 80:80 -v `${pwd}` /../src:/src sda-docker-demo”. However, in case you are utilizing sh/bash then right here is how you’d implement this in your docker command.

docker run-p 80:80 -v `$(pwd)` /../src:/src sda-docker-demo

Conclusion

The docker invalid reference format error is an error you get for not abiding by the conventions of naming a docker picture. In this publish, you’ve realized there are numerous causes of this error and numerous options to it. Here is a fast recap of the information:

  • With docker, failure to stay to the syntax of naming photographs is the primary reason for this error
  • One instance includes appending particular characters on the finish or begin of a docker picture identify
  • Using uppercase characters within the docker identify will set off this error
  • To resolve this error, abide by the naming conventions in Docker
  • One manner is to keep away from utilizing uppercase characters in your docker picture identify

Now that you already know the root reason for this error, you’ll be able to simply pinpoint and resolve it every time your docker instructions set off it.

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