ChangeFeed : Adds ChangeFeedStartFrom to support StartTimes x FeedRanges

[bchong95]

Internal ChangeFeed : Adds StartFrom x FeedRange

Description

This PR removes FeedRange from ChangeFeedRequestOptions and instead moves it as a cross product to StartFrom. This is to avoid a user setting a continuation token (that already has the FeedRange) with another FeedRange. The full details for that can be found here: #1686.

This implies that we need to remove the PartitionKey + ChangeFeedRequestOptions overloads, since users might set PartitionKey and the FeedRange in ChangeFeedRequestOptions, which is ambigious for which should win. This implies that FeedRange needs a static constructor for users to create a FeedRange that points to a single logical partition:

public static FeedRange CreateFromPartitionKey(PartitionKey partitionKey) => new FeedRangePartitionKey(partitionKey);

With that in mind the current API for StartFrom looks like this:

public abstract class ChangeFeedStartFrom
{
	public static ChangeFeedStartFrom Now() => Now(FeedRangeEpk.FullRange);

	public static ChangeFeedStartFrom Now(FeedRange feedRange);

	public static ChangeFeedStartFrom Time(DateTime dateTime) => Time(dateTime, FeedRangeEpk.FullRange);

	public static ChangeFeedStartFrom Time(DateTime dateTime, FeedRange feedRange);

	public static ChangeFeedStartFrom ContinuationToken(string continuation) => new ChangeFeedStartFromContinuation(continuation);

	public static ChangeFeedStartFrom Beginning() => Beginning(FeedRangeEpk.FullRange);

	public static ChangeFeedStartFrom Beginning(FeedRange feedRange);
}

Which is a slight variation from what is proposed in the github issue. It opts for additional methods instead of overloads or optional parameters. This is to make the intellisense on the public API more clear and also allows for non compile time default values (like EpkRange.FullRange).

The ChangeFeed API now looks like this:

public override FeedIterator GetChangeFeedStreamIterator(
	ChangeFeedStartFrom changeFeedStartFrom,
	ChangeFeedRequestOptions changeFeedRequestOptions = null)

public override FeedIterator<T> GetChangeFeedIterator<T>(
	ChangeFeedStartFrom changeFeedStartFrom,
	ChangeFeedRequestOptions changeFeedRequestOptions = null)

With ChangeFeedStartFrom as a required field. This eliminates ambiguous defaults.

A new derived class from start from was also added (StartFromContinuationAndFeedRange), which is not exposed to the user. Essentially a user will pass in StartFromContinuation and we will deserialize and convert it to a StartFromContinuationAndFeedRange.

[sboshra]

The base branch was changed.

[kirankumarkolli]

Which scenarios void this assert?

[j82w]

This actually looks like a bug I introduced. I will send out a fix later today.

[bchong95]

We run all tests in release mode, so adding a debug assert doesn't actually do anything. We should add code analysis to avoid this.

[j82w]

The fix is merged in.

[kirankumarkolli]

    ///     FeedRange = feedRanges[0]

Refresh, also any other related documentation impact.

---

Refers to: Microsoft.Azure.Cosmos/src/Resource/Container/Container.cs:1233 in d098458. [](commit_id = d098458, deletion_comment = False)

[kirankumarkolli]

    ///     FeedRange = feedRanges[0]

Refresh

---

Refers to: Microsoft.Azure.Cosmos/src/Resource/Container/Container.cs:1191 in d098458. [](commit_id = d098458, deletion_comment = False)

[ealsur]

Please update the public examples on the Container.cs file with the new API

[ghost]

Closing due to in-activity, pease feel free to re-open.