Build and cache relay list per configuration excluding Release

[buggmagnet]

This PR changes the relays-prebuild.sh script to :

• Cache a relay list per configuration
• Automatically switch the relays.json file to the correct configuration
• Not download the relays list when the build scheme specifies a Release build.

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This change is 

[linear]

IOS-1097 Always refresh relay file opportunistically

[pinkisemils]

Reviewed 1 of 1 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved

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ios/relays-prebuild.sh line 10 at r1 (raw file):

# Do not download the file for release builds, a different script will take care of that.
if [ "$CONFIGURATION" == "Release" ]; then
  return 0

This is technically out of spec, but this script should fail loudly if there is no relay list exists at this point, IMO. Failing loudly would help us identify a case where we have forgotten to commit the relay list for a given release build :)

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ios/relays-prebuild.sh line 13 at r1 (raw file):

fi

BACKUP_FILE="$CONFIGURATION_TEMP_DIR/relays.json"

Why not namespace it like $CONFIGURATION_TEMP_DIR/relays.json.$CONFIGURATION? Then we're not overwriting the other file when switching between builds, this can help with the not that likely case of allowing builds to continue to work when offline.

[rablador]

Will this implementation do what we want it to do?

Reviewed 1 of 1 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved

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ios/relays-prebuild.sh line 13 at r1 (raw file):

Previously, pinkisemils (Emīls Piņķis) wrote…

Why not namespace it like $CONFIGURATION_TEMP_DIR/relays.json.$CONFIGURATION? Then we're not overwriting the other file when switching between builds, this can help with the not that likely case of allowing builds to continue to work when offline.

Is this directory ever cleared? If not, after being built once the same file will be reused every time, which isn't what we want.

[buggmagnet]

Reviewable status: complete! all files reviewed, all discussions resolved

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ios/relays-prebuild.sh line 13 at r1 (raw file):

Why not namespace it

As the name implies, $CONFIGURATION_TEMP_DIR is a temp directory specifically tied to the $CONFIGURATION parameter, as such the whole folder is name spaced instead of the file itself.

Is this directory ever cleared?

Yes, when you issue a clean command to Xcode

We get to control exactly when we want a fresh file.

[buggmagnet]

Reviewable status: 0 of 1 files reviewed, all discussions resolved (waiting on @pinkisemils and @rablador)

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ios/relays-prebuild.sh line 10 at r1 (raw file):

Previously, pinkisemils (Emīls Piņķis) wrote…

This is technically out of spec, but this script should fail loudly if there is no relay list exists at this point, IMO. Failing loudly would help us identify a case where we have forgotten to commit the relay list for a given release build :)

I added that loud failure, but I didn't test it from the CLI. I couldn't see any echo statements from within Xcode, so I'm hoping that running a build from the CLI (Which is what the CI is doing I assume) will display the error message.

[rablador]

N/m that, I forgot to remove comment.

Reviewable status: 0 of 1 files reviewed, all discussions resolved (waiting on @pinkisemils)

[rablador]

Reviewed 1 of 1 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved

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ios/relays-prebuild.sh line 13 at r1 (raw file):

Previously, buggmagnet wrote…

Why not namespace it

As the name implies, $CONFIGURATION_TEMP_DIR is a temp directory specifically tied to the $CONFIGURATION parameter, as such the whole folder is name spaced instead of the file itself.

Is this directory ever cleared?

Yes, when you issue a clean command to Xcode

We get to control exactly when we want a fresh file.

That's nice I think, although a little opaque to the user. Maybe we should add a line to the ReadMe to indicate this.