migrations: host-containers default version migration redux and new common migration 'ReplaceTemplateMigration'

[etungsten]

Issue #, if available: Partially addresses #685

Description of changes:
Bumps the default version of the host container images.
Adds new common migration helper ReplaceTemplateMigration.
Adds new migration binary for bumping the default host containers version from v0.2 to v0.3.

Testing done:
Forward migration:

Updating template and value of 'settings.host-containers.admin.source' on upgrade

Changing template of 'settings.host-containers.admin.source' from '328549459982.dkr.ecr.{{ settings.aws.region }}.amazonaws.com/thar-admin:v0.2' to '328549459982.dkr.ecr.{{ settings.aws.region }}.amazonaws.com/bottlerocket-admin:v0.3'

Changing value of 'settings.host-containers.admin.source' from '328549459982.dkr.ecr.us-west-2.amazonaws.com/thar-admin:v0.2' to '328549459982.dkr.ecr.us-west-2.amazonaws.com/bottlerocket-admin:v0.3'

Updating template and value of 'settings.host-containers.control.source' on upgrade

Changing template of 'settings.host-containers.control.source' from '328549459982.dkr.ecr.{{ settings.aws.region }}.amazonaws.com/thar-control:v0.2' to '328549459982.dkr.ecr.{{ settings.aws.region }}.amazonaws.com/bottlerocket-control:v0.3'

Changing value of 'settings.host-containers.control.source' from '328549459982.dkr.ecr.us-west-2.amazonaws.com/thar-control:v0.2' to '328549459982.dkr.ecr.us-west-2.amazonaws.com/bottlerocket-control:v0.3'

Backward migration:

Changing template of 'settings.host-containers.admin.source' from '328549459982.dkr.ecr.{{ settings.aws.region }}.amazonaws.com/bottlerocket-admin:v0.3' to '328549459982.dkr.ecr.{{ settings.aws.region }}.amazonaws.com/thar-admin:v0.2'

Changing value of 'settings.host-containers.admin.source' from '328549459982.dkr.ecr.us-west-2.amazonaws.com/bottlerocket-admin:v0.3' to '328549459982.dkr.ecr.us-west-2.amazonaws.com/thar-admin:v0.2'

Updating template and value of 'settings.host-containers.control.source' on downgrade

Changing template of 'settings.host-containers.control.source' from '328549459982.dkr.ecr.{{ settings.aws.region }}.amazonaws.com/bottlerocket-control:v0.3' to '328549459982.dkr.ecr.{{ settings.aws.region }}.amazonaws.com/thar-control:v0.2'

Changing value of 'settings.host-containers.control.source' from '328549459982.dkr.ecr.us-west-2.amazonaws.com/bottlerocket-control:v0.3' to '328549459982.dkr.ecr.us-west-2.amazonaws.com/thar-control:v0.2'

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[etungsten]

@tjkirch Now that the host-containers source is templated. What do you think is the best way to account for other possible regions on backwards migration? (Currently the images are only available in us-west-2)

[tjkirch]

@etungsten Unfortunately we can't just check the version/suffix because customers could use the same versioning. We need to make sure the source account and version match, at least. One way would be a pattern match that reuses the source region. A simpler way would be confirming the source account matches, then just replacing the suffix. (We have all the data, so we could regenerate from the pattern using schnauzer, but that seems a bit much and assume some things...)

[tjkirch]

@etungsten Actually, using schnauzer may not be such a bad idea. Through the MigrationData, we already have all of the data and metadata we would need to generate the old value (to check for a match) and the new value, without needing the API. We've rebooted if we're running migrations, so we know we have the region setting. Worth a try?

Something like:

const NEW_TEMPLATE = "<same as existing template but with new version>";
if let Some(existing_source) = input.data.get("settings.host-containers.control.source") {
  if let Some(metadata) = input.metadata.get("settings.host-containers.control.source") {
    if let Some(template) = metadata.get("template") {
      let registry = schnauzer::build_template_registry();
      let old = registry.render_template(template, input.data)?;
      if old == existing_source {
        let new = registry.render_template(NEW_TEMPLATE, input.data)?;
        println!("{}", new);
      } // elses to handle missing data
...

[etungsten]

Adds new common migration helper ReplaceTemplateMigration. Thanks @tjkirch, for all the help with this!
Renames host-containers migrations binary.

[zmrow]

🍔

[tjkirch]

Side note: whether we include the concrete migration for v0.3 depends on out-of-band discussions today regarding the breaking-ness of our next release. (If it's a full break release with no upgrade, we won't need the migration.) We still want the common migration code because we'll need it soon regardless.

[etungsten]

Addresses @tjkirch 's comments.

• Created new helper function update_template_and_data

Tested and things still work.

[etungsten]

Drop dependency on simplelog

[tjkirch]

Would you please confirm/update the testing?

[etungsten]

Addresses @tjkirch 's comments.

Tested new changes and things still work as expected:
Forward

Updating template and value of 'settings.host-containers.admin.source' on upgrade

Changing template of 'settings.host-containers.admin.source' from '328549459982.dkr.ecr.{{ settings.aws.region }}.amazonaws.com/bottlerocket-admin:v0.3' to '328549459982.dkr.ecr.{{ settings.aws.region }}.amazonaws.com/thar-admin:v0.2'

Changing value of 'settings.host-containers.admin.source' from '328549459982.dkr.ecr.us-west-2.amazonaws.com/bottlerocket-admin:v0.3' to '328549459982.dkr.ecr.us-west-2.amazonaws.com/thar-admin:v0.2'

Updating template and value of 'settings.host-containers.control.source' on upgrade

Changing template of 'settings.host-containers.control.source' from '328549459982.dkr.ecr.{{ settings.aws.region }}.amazonaws.com/bottlerocket-control:v0.3' to '328549459982.dkr.ecr.{{ settings.aws.region }}.amazonaws.com/thar-control:v0.2'

Changing value of 'settings.host-containers.control.source' from '328549459982.dkr.ecr.us-west-2.amazonaws.com/bottlerocket-control:v0.3' to '328549459982.dkr.ecr.us-west-2.amazonaws.com/thar-control:v0.2'

Backward:

Updating 'settings.host-containers.admin.source''s template and value on downgrade

Changing template of 'settings.host-containers.admin.source' from '328549459982.dkr.ecr.{{ settings.aws.region }}.amazonaws.com/thar-admin:v0.2' to '328549459982.dkr.ecr.{{ settings.aws.region }}.amazonaws.com/bottlerocket-admin:v0.3'

Changing value of 'settings.host-containers.admin.source' from '328549459982.dkr.ecr.us-west-2.amazonaws.com/thar-admin:v0.2' to '328549459982.dkr.ecr.us-west-2.amazonaws.com/bottlerocket-admin:v0.3'

Updating 'settings.host-containers.control.source''s template and value on downgrade

Changing template of 'settings.host-containers.control.source' from '328549459982.dkr.ecr.{{ settings.aws.region }}.amazonaws.com/thar-control:v0.2' to '328549459982.dkr.ecr.{{ settings.aws.region }}.amazonaws.com/bottlerocket-control:v0.3'

Changing value of 'settings.host-containers.control.source' from '328549459982.dkr.ecr.us-west-2.amazonaws.com/thar-control:v0.2' to '328549459982.dkr.ecr.us-west-2.amazonaws.com/bottlerocket-control:v0.3'

[tjkirch]

It looks like the forward/backward testing sections are backwards? And the messages aren't symmetrical (forward was updated but not backward, or vice versa, not sure because the header seems backwards), can we fix that?

[edit] Ah, I see, the force-push after the testing fixed that message. Would be nice to keep the testing in the description up to date, if it's changed, and just confirm in update-related comments that it was retested.

[etungsten]

Addressed @tjkirch 's comments.
Updated PR description with new testing results

[etungsten]

Force push above rebases onto develop