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Document Compose's syntax for variable defaults - #84

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londoncalling merged 2 commits into
docker:vnext-composefrom
nVitius:var-interpolation-docs
Oct 31, 2016
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Document Compose's syntax for variable defaults#84
londoncalling merged 2 commits into
docker:vnext-composefrom
nVitius:var-interpolation-docs

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@nVitius

@nVitiusnVitius commented Oct 5, 2016

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This feature was not supported previously, but
was added in docker/compose#3108

@aanand

aanand commented Oct 11, 2016

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Thanks! We should document both forms of the inline default syntax:

  • ${VAR-default} (only fall back if VAR is unset)
  • ${VAR:-default} (fall back if VAR is unset or empty)

mdlinville pushed a commit that referenced this pull request Oct 11, 2016
Dan Liew
In "Task 2. Start a development container" make sure the Docker source
c503045
code is bind mounted into the development container. Otherwise in Task 3
changes made to the source code outside the container will not be
visible inside the container.
This is basically the change made by @mbtamuli in #84 but that change
seems to have been abandoned.
Signed-off-by: Dan Liew <daniel.liew@imperial.ac.uk>
@johndmulhausen

johndmulhausen commented Oct 11, 2016

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Question: Is this for upcoming Docker Compose functionality or is this functionality already released?

@nVitius

nVitius commented Oct 11, 2016

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@aanand: thanks, I missed that part.
@johndmulhausen: It looks like it's slated for 1.9.

@mdlinville

mdlinville commented Oct 11, 2016

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In that case, please rebase this on the branch vnext-compose.

@nVitius
nVitiusforce-pushed the var-interpolation-docs branch from 132b503 to bf39724CompareOctober 12, 2016 16:48
@nVitius
nVitius changed the base branch from master to vnext-composeOctober 12, 2016 16:49
@nVitius
Document Compose's syntax for variable defaults
bb7661a
This feature was not supported previously, but
was added in docker/compose#3108
@nVitius
nVitiusforce-pushed the var-interpolation-docs branch from bf39724 to bb7661aCompareOctober 12, 2016 16:50
@nVitius

nVitius commented Oct 12, 2016

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Okay, I rebased over the vnext-compose branch and added the comment regarding the different syntax.

mdlinville
mdlinville suggested changes Oct 12, 2016
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Thanks, this is looking good. I added a couple of style suggestions which I think may make this easier to understand. Please let me know what you think about these.

Comment threadcompose/compose-file.md

Both `$VARIABLE` and `${VARIABLE}` syntax are supported. Extended shell-style
features, such as `${VARIABLE-default}` and `${VARIABLE/foo/bar}`, are not
In the case of environment variables that are not set, it is also possible to

@mdlinvillemdlinvilleOct 12, 2016

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Consider "you can" instead of "it is possible to".

Comment threadcompose/compose-file.md Outdated
Both `$VARIABLE` and `${VARIABLE}` syntax are supported. Extended shell-style
features, such as `${VARIABLE-default}` and `${VARIABLE/foo/bar}`, are not
In the case of environment variables that are not set, it is also possible to
define default values like so: `${VARIABLE:-default}`. In this case, Compose

@mdlinvillemdlinvilleOct 12, 2016•
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Consider rewriting this a bit:

...define default values using one of the following syntax variants.

  • To provide a default value which will be used if VARIABLE is unset or empty:

    ${VARIABLE:-default}

  • To provide a default value if VARIABLE is empty:

    ${VARIABLE-default}

Both...

Victoria Bialas
incorporated misty's comments
980956e
Signed-off-by: Victoria Bialas <victoria.bialas@docker.com>
@londoncalling

londoncalling commented Oct 31, 2016

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@mstanleyjones can you look at the updates I made here per your comments, and if this looks good, review and approve? Then either you or I can merge this...?

@mdlinville

mdlinville commented Oct 31, 2016

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LGTM, thought I would still reconsider "it is possible to"...

@londoncalling
londoncalling merged commit 1676a84 into docker:vnext-composeOct 31, 2016
@johndmulhausenjohndmulhausen added this to the compose/1.9.0 milestone Nov 11, 2016
joaofnfernandes pushed a commit to joaofnfernandes/docker.github.io that referenced this pull request Aug 16, 2017
Jim GalasynJoao Fernandes
Add China registry mirror section (docker#84)
a422b19
joaofnfernandes pushed a commit to joaofnfernandes/docker.github.io that referenced this pull request Aug 16, 2017
Jim GalasynJoao Fernandes
Add China registry mirror section (docker#84)
2a718b9
JimGalasyn pushed a commit that referenced this pull request Aug 16, 2017
Jim Galasyn
Add China registry mirror section (#84)
ec441b3
shin- pushed a commit to shin-/docker.github.io that referenced this pull request Aug 19, 2017
Jim Galasyn@shin-
Add China registry mirror section (docker#84)
faf2440
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