Retain custom environment variables in env-config.json between translation - #2131
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| // ReplaceEnvConfigFile merges the given values into the env-config.json at path, | ||
| // first removing keysToRemove so stale values don't persist. | ||
| func ReplaceEnvConfigFile(path string, values map[string]string, keysToRemove []string) error { |
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I know that this function is NOT atomic so it can technically corrupt the env.json via a race condition. I think it should be okay since we have the 0644; however, if the user sets to run CWAgent as X user, is it possible for that user to right to the env-config.json and cause the race condition?
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I suppose if they're writing to it at the exact same time as the translation. I think that's difficult to avoid.
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Adds a 'set-env' action to the Linux and Windows ctl scripts that wraps the agent binary's internal -setenv/-envconfig flags, so callers (e.g. setup scripts) no longer need to invoke the raw agent binary or hardcode the env-config.json path. Usage: amazon-cloudwatch-agent-ctl -a set-env -e KEY=VALUE amazon-cloudwatch-agent-ctl.ps1 -a set-env -e KEY=VALUE Keys set this way are retained across config translations (#2131) unless they are translator-managed keys.
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Adds a 'set-env' action to the Linux and Windows ctl scripts that wraps the agent binary's internal -setenv/-envconfig flags, so callers (e.g. setup scripts) no longer need to invoke the raw agent binary or hardcode the env-config.json path. Usage: amazon-cloudwatch-agent-ctl -a set-env -e KEY=VALUE amazon-cloudwatch-agent-ctl.ps1 -a set-env -e KEY=VALUE Keys set this way are retained across config translations (#2131) unless they are translator-managed keys.
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Description of the issue
When the config translator runs (e.g. on
fetch-config), it overwritesenv-config.jsonentirely. Any values written to that file outside of translation are lost. This means custom environment variables are not retained.Description of changes
Adds file-level helpers to the existing
cfg/envconfigpackage (ReadFile,LoadFile,MergeFile) that centralize allenv-config.jsonI/O.The key behavioral change is in
TranslateJSONMapToEnvConfigFile. Instead of overwritingenv-config.json, it now callsMergeFilewithtoenvconfig.ManagedKeys, the explicit set of keys that translation owns. On each translation, managed keys are reset to reflect the current JSON config (clearing stale values), while unmanaged keys are preserved.Since the agent is trying to retain custom environment variables now, an incorrectly formatted
env-config.jsonwill prevent the agent from starting rather than wiping the values.License
By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.
Tests
Added unit tests. Built and tested on EC2 instance.
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