eve/dist/src/client/open-stream.js

Filesystem-first framework for durable backend AI agents that run anywhere.

import{createEveSessionStreamRoutePath}from"#protocol/routes.js";import{EVE_STREAM_CONTROL_VERSION,EVE_STREAM_CONTROL_VERSION_QUERY,EVE_STREAM_TAIL_INDEX_HEADER}from"#protocol/message.js";import{isStreamDisconnectError,readNdjsonStream}from"#client/ndjson.js";import{readMessageStreamVersion}from"#client/stream-version.js";import{ClientError}from"#client/client-error.js";import{createClientUrl}from"#client/url.js";const DEFAULT_STREAM_RECONNECT_POLICY={retryableErrorStatuses:new Set([404,409,425,500,502,503,504]),streamIdleReconnectPolicy:{baseDelayMs:250,maxAttempts:5,maxDelayMs:4e3},streamOpenReconnectPolicy:{baseDelayMs:250,maxAttempts:12,maxDelayMs:5e3}},NO_STREAM_RECONNECT_POLICY={...DEFAULT_STREAM_RECONNECT_POLICY,streamIdleReconnectPolicy:{...DEFAULT_STREAM_RECONNECT_POLICY.streamIdleReconnectPolicy,maxAttempts:0},streamOpenReconnectPolicy:{...DEFAULT_STREAM_RECONNECT_POLICY.streamOpenReconnectPolicy,maxAttempts:1}};function resolveRetryPolicy(e,t){return{...t,...e}}function resolveStreamReconnectPolicy(e,t=!1){if(e&&`reconnect`in e&&e.reconnect===!1)return NO_STREAM_RECONNECT_POLICY;let n=e;return{retryableErrorStatuses:n?.retryableErrorStatuses?new Set(n.retryableErrorStatuses):DEFAULT_STREAM_RECONNECT_POLICY.retryableErrorStatuses,streamIdleReconnectPolicy:resolveRetryPolicy(n?.streamIdleReconnectPolicy,{...DEFAULT_STREAM_RECONNECT_POLICY.streamIdleReconnectPolicy,maxAttempts:t?1/0:DEFAULT_STREAM_RECONNECT_POLICY.streamIdleReconnectPolicy.maxAttempts}),streamOpenReconnectPolicy:resolveRetryPolicy(n?.streamOpenReconnectPolicy,DEFAULT_STREAM_RECONNECT_POLICY.streamOpenReconnectPolicy)}}async function*followStreamIterable(e){if(e.follow===!1&&e.startIndex<0)throw Error(`stream({ follow: false }) requires a nonnegative startIndex; a tail-relative cursor cannot be bounded.`);let resolvePolicy=()=>resolveStreamReconnectPolicy(e.resolveReconnectPolicy===void 0?e.streamReconnectPolicy:e.resolveReconnectPolicy(),e.keepAlive),t=resolvePolicy(),n=t.streamIdleReconnectPolicy,r=e.startIndex,i=n.baseDelayMs,a=0,o=!0,s,c=!1;for(;;){t=resolvePolicy(),n=t.streamIdleReconnectPolicy;let l;try{l=await openStreamBody({...e,retryPolicy:t,startIndex:r,requestTailIndex:(e.follow===!1||e.onCaughtUp!==void 0)&&s===void 0})}catch(t){if(e.signal?.aborted)return;throw t}if((e.follow===!1||e.onCaughtUp!==void 0)&&s===void 0&&(s=l.tailIndex,s===void 0))throw l.close(),Error(`stream({ follow: false }) requires the server to report the ${EVE_STREAM_TAIL_INDEX_HEADER} header. The agent may be running an older eve version.`);if(!c&&s!==void 0&&r>s&&(c=!0,e.onCaughtUp?.()),e.follow===!1&&s!==void 0&&r>s){l.close();return}let u=!1,d=!1;try{for await(let t of readNdjsonStream(l.body,{signal:e.signal,controlVersion:l.controlVersion,idleTimeoutMs:e.streamReadIdleTimeoutMs??15e3,onLeaseEnded:()=>{d=!0},streamVersion:l.streamVersion}))if(r+=1,u=!0,i=n.baseDelayMs,a=0,yield t,!c&&s!==void 0&&r>s&&(c=!0,e.onCaughtUp?.()),e.follow===!1&&s!==void 0&&r>s)return}catch(e){if(!isStreamDisconnectError(e))throw e}finally{l.close()}if(n=resolvePolicy().streamIdleReconnectPolicy,e.signal?.aborted||e.startIndex<0||n.maxAttempts===0)return;if(!d){if(!u&&!o&&(a+=1)>=n.maxAttempts||(o=!1,await sleep(i,e.signal),e.signal?.aborted))return;i=Math.min(i*2,n.maxDelayMs)}}}async function openStreamBody(e){let t=e.retryPolicy??resolveStreamReconnectPolicy(e.streamReconnectPolicy,e.keepAlive),n=t.streamOpenReconnectPolicy,r,i,a,o=n.baseDelayMs,s=e.startIndex>=0&&t.streamIdleReconnectPolicy.maxAttempts>0?EVE_STREAM_CONTROL_VERSION:void 0,c={};s!==void 0&&(c[EVE_STREAM_CONTROL_VERSION_QUERY]=s),e.startIndex!==0&&(c.startIndex=String(e.startIndex)),e.requestTailIndex===!0&&(c.includeTailIndex=`1`);for(let l=0;l<n.maxAttempts;l+=1){e.signal?.throwIfAborted();let u=createClientUrl(e.host,createEveSessionStreamRoutePath(e.sessionId),Object.keys(c).length>0?c:void 0),d=await e.resolveHeaders();e.signal?.throwIfAborted();let f=new AbortController,p=e.signal?AbortSignal.any([e.signal,f.signal]):f.signal,m;try{m=await fetch(u,{cache:`no-store`,headers:d,redirect:e.redirect,signal:p})}catch(t){if(e.signal?.aborted||!isStreamDisconnectError(t)||l===n.maxAttempts-1)throw t;await sleep(o,e.signal),o=Math.min(o*2,n.maxDelayMs);continue}if(m.ok){if(!m.body)throw new ClientError(m.status,`Response body is null.`,m.headers);let e=!1;return{body:m.body,close:()=>{e||(e=!0,m.body?.cancel().catch(()=>{}),f.abort())},controlVersion:s,streamVersion:readMessageStreamVersion(m.headers),tailIndex:parseTailIndexHeader(m.headers)}}if(r=m.status,i=await m.text(),a=m.headers,!t.retryableErrorStatuses.has(m.status))throw new ClientError(m.status,i,m.headers);l<n.maxAttempts-1&&(await sleep(o,e.signal),o=Math.min(o*2,n.maxDelayMs))}throw new ClientError(r??0,i??`Failed to open message stream.`,a)}function parseTailIndexHeader(e){let t=e.get(EVE_STREAM_TAIL_INDEX_HEADER);if(t===null||!/^-?\d+$/.test(t))return;let n=Number(t);return Number.isSafeInteger(n)?n:void 0}async function sleep(e,t){t?.aborted||await new Promise(n=>{let onAbort=()=>{clearTimeout(r),n()},r=setTimeout(()=>{t?.removeEventListener(`abort`,onAbort),n()},e);t?.addEventListener(`abort`,onAbort,{once:!0})})}export{followStreamIterable,openStreamBody,sleep};