Hi Colin,
I've changed the KIP to have a composite object returned from get(). It's
probably the most straightforward option. Please let me know if you have
any other concerns.
Thanks,
Robert
On Thu, May 17, 2018 at 11:44 AM, Robert Yokota <rayok...@gmail.com> wrote:
>
>
> Hi Colin,
>
> My last response was not that clear, so let me back up and explain a bit
> more.
>
> Some secret managers, such as Vault (and maybe Keywhiz) have the notion of
> a lease duration or a TTL for a path. Every path can have a different
> TTL. This is period after which the value of the keys at the given path
> may be invalid. It can be used to indicate a rotation will be done. In
> the cause of the Vault integration with AWS, Vault will actually delete the
> secrets from AWS at the moment the TTL expires. A TTL could be used by
> other ConfigProviders, such as a FileConfigProvider, to indicate that all
> the secrets at a given path (file), will be rotated on a regular basis.
>
> I would like to expose the TTL in the APIs somewhere. The TTL can be made
> available at the time get() is called. Connect already has a built in
> ScheduledExecutor, so Connect can just use the TTL to schedule a Connector
> restart. Originally, I had exposed the TTL in a ConfigContext interface
> passed to the get() method. To reduce the number of APIs, I placed it on
> the onChange() method. This means at the time of get(), onChange() would
> be called with a TTL. The Connector's implementation of the callback would
> use onChange() with the TTL to schedule a restart.
>
> If you think this is overloading onChange() too much, I could add the
> ConfigContext back to get():
>
>
> Map<String, String> get(ConfigContext ctx, String path);
>
> public interface ConfigContext {
>
> void willExpire(String path, long ttl);
>
> }
>
>
>
> or I could separate out the TTL method in the callback:
>
>
> public interface ConfigChangeCallback {
>
> void willExpire(String path, long ttl);
>
> void onChange(String path, Map<String, String> values);
> }
>
>
>
> Or we could return a composite object from get():
>
> ConfigData get(String path);
>
> public class ConfigData {
>
> Map<String, String> data;
> long ttl;
>
> }
>
>
> Do you have a preference Colin?
>
> Thanks,
> Robert
>
>
> On Thu, May 17, 2018 at 9:27 AM, Colin McCabe <cmcc...@apache.org> wrote:
>
>> Hi Robert,
>>
>> Hmm. I thought that if you're using ConfigChangeCallback, you are
>> relying on the ConfigProvider to make a callback to you when the
>> configuration has changed. So isn't that always the "push model" (where
>> the ConfigProvider pushes changes to Connect). If you want the "pull
>> model" where you initiate updates, you can simply call ConfigProvider#get
>> directly, right?
>>
>> The actual implementation of ConfigProvider subclasses will depend on the
>> type of configuration storage mechanism on the backend. In the case of
>> Vault, it sounds like we need to have something like a ScheduledExecutor
>> which re-fetches keys after a certain amount of time.
>>
>> As an aside, what does a "lease duration" mean for a configuration key?
>> Does that mean Vault will reject changes to the configuration key if I try
>> to make them within the lease duration? Or is this like a period after
>> which a password is automatically rotated?
>>
>> On Wed, May 16, 2018, at 22:25, Robert Yokota wrote:
>> > Hi Colin,
>> >
>> > > With regard to delayMs, can’t we just restart the
>> > > Connector when the keys are actually changed?
>> >
>> > Currently the VaultConfigProvider does not find out when values for keys
>> > have changed. You could do this with a poll model (with a
>> > background thread in the ConfigProvider), but since for each key-value
>> > pair, Vault provides a lease duration stating exactly when a value for a
>> > key will change in the future, this is an alternative model of just
>> passing
>> > the lease duration to the client (in this case the Connector), to allow
>> it
>> > to determine what to do (such as schedule a restart). This may allow
>> one
>> > to avoid the complexity of figuring out a proper poll interval (with
>> lease
>> > durations of varying periods), or worrying about putting too much load
>> on
>> > the secrets manager by polling too often.
>>
>> Those things are still concerns if the Connector is polling, right?
>> Perhaps the connector poll too often and puts too much load on Vault. And
>> so forth. It seems like this problem needs to be solved either way (and
>> probably can be solved with reasonable default minimum fetch intervals).
>>
>> best,
>> Colin
>>
>>
>> > In other words, by adding this
>> > one additional parameter, a ConfigProvider can provide both push and
>> pull
>> > models to clients, perhaps with an additional configuration parameter to
>> > the ConfigProvider to determine which model (push or poll) to use.
>> >
>> > Thanks,
>> > Robert
>> >
>> > On Wed, May 16, 2018 at 9:56 PM, Colin McCabe <cmcc...@apache.org>
>> wrote:
>> >
>> > > Thanks, Robert. With regard to delayMs, can’t we just restart the
>> > > Connector when the keys are actually changed? Or is the concern that
>> > > this would lengthen the effective key rotation time? Can’t the user
>> > > just configure a slightly shorter key rotation time to counteract
>> > > this concern?
>> > > Regards,
>> > > Colin
>> > >
>> > > On Wed, May 16, 2018, at 19:13, Robert Yokota wrote:
>> > > > Hi Colin,
>> > > >
>> > > > Good questions.
>> > > >
>> > > >
>> > > > > As a clarification about the indirections, what if I have the
>> > > > > connect> configuration key foo set up as ${vault:bar}, and in
>> Vault,
>> > > > have the bar> key set to ${file:baz}?
>> > > > > Does connect get foo as the contents of the baz file? I would
>> > > > > argue that> it should not (and in general, we shouldn't allow
>> > > ConfigProviders to
>> > > > indirect to other
>> > > > > ConfigProviders) but I don't think it's spelled out right now.
>> > > >
>> > > > I've added a clarification to the KIP that further indirections are
>> > > > not> performed even if the values returned from ConfigProviders
>> have the
>> > > > variable syntax.
>> > > >
>> > > >
>> > > > > What's the behavior when a config key is not found in Vault
>> > > > > (or other> ConfigProvider)? Does the variable get replaced with
>> the
>> > > empty
>> > > > string, or> with the literal ${vault:whatever} string?
>> > > >
>> > > > It would remain unresolved and still be of the form
>> > > > ${provider:key}. I've> added a clarification to the KIP.
>> > > >
>> > > >
>> > > > > Do we really need "${provider:[path:]key}", or can it just be
>> > > > ${provider:key}?
>> > > >
>> > > > The path is a separate parameter in the APIs, so I think it's
>> > > > important to> explicitly delineate it in the variable syntax. For
>> > > example, I
>> > > > currently> have a working VaultConfigProvider prototype and the
>> syntax
>> > > for a
>> > > > Vault key> reference looks like
>> > > >
>> > > > db_password=${vault:secret/staging:mysql_password}
>> > > >
>> > > > I think it's important to standardize how to separate the path
>> > > > from the key> rather than leave it to each ConfigProvider to
>> determine a
>> > > possibly
>> > > > different way. This will also make it easier to move secrets from
>> one>
>> > > ConfigProvider to another should one choose to do so.
>> > > >
>> > > >
>> > > > > Do we really need delayMs?
>> > > >
>> > > > One of the goals of this KIP is to allow for secrets rotation
>> without>
>> > > having to modify existing connectors. In the case of the
>> > > > VaultConfigProvider, it knows the lease durations and will be able
>> to>
>> > > schedule a restart of the Connector using an API in the Herder. The
>> > > > delayMs will simply be passed to the Herder.restartConnector(long
>> > > > delayMs,> String connName, Callback cb) method here:
>> > > >
>> > > > https://github.com/rayokota/kafka/blob/secrets-in-connect-
>> > > configs/connect/runtime/src/main/java/org/apache/kafka/
>> > > connect/runtime/Herder.java#L170>
>> > > >
>> > > > Best,
>> > > > Robert
>> > > >
>> > > >
>> > > >
>> > > > On Wed, May 16, 2018 at 6:16 PM, Colin McCabe
>> > > > <cmcc...@apache.org> wrote:>
>> > > > > Thanks, Robert. Looks good overall.
>> > > > >
>> > > > > As a clarification about the indirections, what if I have the
>> > > > > connect> > configuration key foo set up as ${vault:bar}, and in
>> Vault,
>> > > have
>> > > > > the bar> > key set to ${file:baz}? Does connect get foo as the
>> > > contents of
>> > > > > the baz> > file? I would argue that it should not (and in
>> general, we
>> > > > > shouldn't allow> > ConfigProviders to indirect to other
>> > > ConfigProviders) but I
>> > > > > don't think> > it's spelled out right now.
>> > > > >
>> > > > > What's the behavior when a config key is not found in Vault
>> > > > > (or other> > ConfigProvider)? Does the variable get replaced
>> with the
>> > > empty
>> > > > > string, or> > with the literal ${vault:whatever} string?
>> > > > >
>> > > > > Do we really need "${provider:[path:]key}", or can it just be
>> > > > > ${provider:key}? It seems like the path can be rolled up into the
>> > > > > key. So> > if you want to put your connect keys under
>> > > my.connect.path, you
>> > > > > ask for> > ${vault:my.connect.path.jdbc.config}, etc.
>> > > > >
>> > > > > > // A delayMs of 0 indicates an immediate change; a positive
>> > > > > > delayMs> > indicates
>> > > > > > // that a future change is anticipated (such as a lease
>> > > > > > duration)> > > void onChange(String path, Map<String,
>> String>
>> > > values, int
>> > > > > > delayMs);> >
>> > > > > Do we really need delayMs? It seems like if you get a callback
>> with>
>> > > > delayMs set, you don't know what the new values will be, only
>> > > > > that an> > update is coming, but not yet here.
>> > > > >
>> > > > > best,
>> > > > > Colin
>> > > > >
>> > > > >
>> > > > > On Wed, May 16, 2018, at 17:05, Robert Yokota wrote:
>> > > > > > Hello everyone,
>> > > > > >
>> > > > > > After a good round of discussions with excellent feedback and no
>> > > > > > major> > > objections, I would like to start a vote on KIP-297
>> to
>> > > externalize> > secrets
>> > > > > > from Kafka Connect configurations. My thanks in advance!
>> > > > > >
>> > > > > > KIP: <
>> > > > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-
>> > > > > 297%3A+Externalizing+Secrets+for+Connect+Configurations
>> > > > > > >
>> > > > > >
>> > > > > > JIRA: <https://issues.apache.org/jira/browse/KAFKA-6886>
>> > > > > >
>> > > > > > Discussion thread: <
>> > > > > > https://www.mail-archive.com/dev@kafka.apache.org/msg87638.html
>> >
>> > > > > >
>> > > > > > Best,
>> > > > > > Robert
>> > > > >
>> > >
>> > >
>>
>
>
